EXPERIMENTAL HYDATIDOSIS IN THE SUDAN: TRANSMISSION AND NATURAL INFECTION
By Nadia Ahmed Ali Mohamed B.Sc. (Assuit University -Egypt) M.Sc. (Parasitology) University of Khartoum
Supervisor: Prof. Mohamed Magzoub Ahmed Alkan Co. Supervisor: Dr. Khitma Hassan El Malik
Thesis submitted to The University of Khartoum For the fulfillment of the requirements for the degree of Doctor of Philosophy in Parasitology
Department of Parasitology Faculty of Veterinary Medicine University of Khartoum
May 2010 ABSTRACT The work presented in this thesis addressed four main aspects of studies dealing with experimental infections leading to the recovery of adult Echinococcus granulosus worms in the intestines of infected puppies, in- vitro studies involving the nature and biology of isolated protoscolices and intact cysts obtained from the lungs of infected camels and the biological studies of hydatid cysts. Furthermore recorded incident of hydatid cysts in the intermediate hosts were collected Oral experimental infection of puppies with hydatid cysts obtained from infected camels using isolated protoscolices, revealed adult Echinococcus granulosus. The worms were recovered from the small intestines. Higher numbers of worms were obtained in infections from lung hydatid cysts as compared with lower numbers obtained from liver cysts. More worms were collected from the upper parts of the intestines than the lower parts. Experimental feeding of puppies with hydatid cysts obtained from infected cattle, using isolated protoscolices, was not established. No worms were found in the intestines of dogs. However, modification of the infected procedure was used by feeding whole cysts obtained form the lungs and the livers of infected cattle resulted in the establishment of infection. Throughout the experimental work, the infection is established by the detection of eggs of Echinococcus granulosus worms in the faeces of the experimental puppies. Thus the Prepatent period, as evidenced by the time of the first appearance of
eggs in the faeces of experimental puppies, ranged between 31-55 days. In- vitro studies were performed by observing the viability of isolated protoscolices or intact cysts placed in normal saline at room temperature and then in the fridge. At room temperature, 40% of the protoscolices remained active and viable for 4 days. Complete death occurred after 6 days; while 70% of those cysts placed in the fridge remained viable for 5 days and death occurred after 7 days. Death of all protoscolices occurred after 17 days, when intact protoscolices inside hydatid cysts were placed in the fridge. These were followed by in –vivo studies, to examine the infectivity of storage viable protoscolices experimentally in puppies, which yield a successful transmission. Samples of hydatid cysts were collected from slaughtered camels, cattle and sheep in different abattoirs of Khartoum State. No cysts from goats were recovered. The size of cysts, volume of cystic fluid and number of the protoscolices were recorded. Hydatid cysts from camels measured each 9.5 cm. for the maximum length of diameter and 1.3 for the minimum. The total volume of fluid, which was aspirated from the cyst, was 6 to 150 milliliters. Hydatid cysts from cattle were 0.5-10cm. The maximum volume of the fluid inside the cyst was 60 milliliters. The size of the hydatid cyst obtained from sheep ranged between 0.9 cm. to 3.0 cm. but the fluid was mostly too little to be measured. The biological status of the cysts was evaluated visually and microscopically as fertile, sterile, caseated, or calcified.
Out of 149 cysts from camels, 96.4% were found to be fertile. As for cattle, out of 26 hydatid cysts examined only 23.1% were fertile. In case of sheep, hydatid cysts 91.7% were sterile. Official records obtained showed the presence of hydatid cysts in slaughtered camels, cattle, sheep and goats in Khartoum state during the period 1995-2008. The highest infection with the cysts occurred in camels followed by cattle and the lowest was found in sheep; however, goats showed no infection. Information sources regarding human hydatidosis showed, sixteen cases of patients, as intermediate hosts, were infected in Khartoum state during the period 2000- 2009. The maximum size of the diameter of the cyst was 12 cm. and the minimum size was 2 cm. The ages of the patients involved, ranged between 6 and 55 years old.
I am indebted to my supervisor professor Mohamed Magzoub Ahmed for his invaluable guidance with extreme patience and helpful suggestions. I would like to express my grateful thanks and appreciation to my co- supervisor Dr.Khitma Hassan El Malik her advice and continuous encouragement through the course of the study. I would like to thank Professor M. Abdal Hameed Kheer Alsaad, Professor Suad M. Sulaiman and Dr. Amal Mutafa for their assistance and support. My acknowledgment is extend to the staff members of the Department of Histopathology, Khartoum National Health Laboratory and staff members of Histopathology Laboratory, Soba Hospital for offering me the human reports of hydatidosis. I acknowledge the technical help of the staff members of the Department of Parasitology, particularly Mr. Babiker Adalan, and the staff members of the Department of Preventive Medicine, Faculty of Veterinary Medicine, University of Khartoum. I am grateful to assistance of the staff members of Khartoum State Slaughter Houses Corporation and also to the staff member of Albugaa Abattoir, and to the veterinaries Mr. Fakhari, Mr. Ibrahim, M. Elhassan, Mr. Sami, Ms.Ensaff, Mr. M. Gasim, whom help me in collecting the samples for the Study. I wish also to express my gratitude to Mr. Azmi, and all friends who help me during the hard work of rearing puppies throughout this study. I lovely thank my mother for her encouragements and Invocation Allah for me. I feel pleasure and honor in expressing my deep sincere gratitude to my husband, Modawi and my sons, whom get acclimatized to my long working hours, for their encouragements.
CONTENTS Title Page
Abstract I
Acknowledgment IV
Contents V
List of Tables XIII List of Plates VI
List of Figures VI
List of Appendices VI
CHAPTER ONE
Introduction 1
CHAPTER TWO Literature Review 6 1. 2. Classification 6
2. 2. Morphology of Echinococcus granulosus 8
2.2.1. Adult 8
2.2.2. Egg 8
2.2.3. Hydatid cysts (metacestode) 9
The cyst wall 10
The germinal or nucleated layer 10
The laminated layer 10
The hydatid cyst fluid 11 2.3. General Life – Cycle 12
2.3.1. Definitive host. 13
2.3.2. Eggs in the environment 13
2.3.3. Intermediate and accidental hosts. 14
2.3.4. The metacestode stage. 15
2.4. Host Range of Echinococcus granulosus 16
Variations in Echinococcus granulosus 2.5. 17 Epidemiological significance of Echinococcus 2.6. 18 granulosus strains 2.7. Viability of E .granulosus protoscolices at different 20 conditions 2.8. Geographical Distribution and Prevalence 21
2.9. Echinococcus granulosus in Africa 24
2.9.1. North African countries 24
2.9.2. Sub- Saharan Africa 25
2.10. Human cystic echinococcosis 25
2.11. Cystic Echinococcosis in Livestock 26
2.12. Factors associated with persistence, emergence, or 27 reemergence of hydatidosis
2.13. Cystic Echinococcosis in Humans 27
2.13. 1. The Course of the infection 27
2.13. 2. Human hydatidosis in Africa and the Sudan 32
2. 14. Research done in the Sudan 34
2.15. Animal host and transmission cycle of 37 Echinococcus granulosus
2.16. Diagnosis 39
2.16. 1. In the definitive host 39
2.16. 2. In the intermediate hosts 40
2.16. 3. In Human 41
2. 17. Control and eradication programs 41
2. 18. Control Options and Prevention 42
2.19 Precautions 43
CHAPTER THREE
Materials and Methods 45
Experimental infection: Infection of dogs with E.
3.1 granulosus using fresh Hydatid cysts from camels and cattle 45 Experimental animals 3.1.1. 45 Experimental Design 3.1.2. 46
3. 1. 3. The Infected Procedures 47
1.3.1. The parasite 47
3.1.3.2. Examination for Eggs 50 Parasite Recovery 3.1.3.3. 50
3. 1. 4. Precautions 51
3.2. The effect of temperature on the viability, 52 survival time and infectivity of hydatid cysts
3.2.1 Testing the Viability and the Survival Time of the Protoscolices of Echinococcus granulosus 52 (In-Vitro)
3. 2. 2. Experimental Transmission Using Protoscolices of 54 Echinococcus granulosus stored in the Refrigerator
3.3. Studies on Hydatid Cyst biology 55
3. 3.1. The Diameter of the Cysts 58
3.3. 2. The Volume of the Cyst’s Fluid 58
3.3. 3. The Status of the cysts 58
3. 3. 4. The Form of the Cyst’s Fluid 58
3.3. 5. Viability of the Cysts 59
The number of the protoscoleces per cyst 3. 3. 6. 59
3.4. Records of Hydatid Cysts in the 61 intermediate host
3. 4. 1. Record of Hydatid Cysts from Slaughtered Animals 61 in Khartoum State (1995 – 2008)
3. 4. 2. Recorded Cases of human hydatidosis in Khartoum 61 State, (2000- 2009) Information Sources: 3. 4.2.1. 61
CHAPTER FOUR 62 RESULT
4.1 Experimental Infection 62
4. 1.1. Transmission of hydatid disease from camels to dogs 62
4. 1.1.1. Infection of puppies by protoscolices from naturally 62 infected Lungs (Group 1)
4.1.1.1.1. The pre- patent period 62
4.1.1.1.2. The infectivity of the worms 63
4.1.1.1.3. Distributions of the worms 65 Transmission from naturally infected livers of 4. 1.1.2. 70 Camels (Group 2) 4.1.1.2.1. The pre- patent period 70
4.1.1.2.2. The infectivity of the worms 70
4. 1. 2. Transmission from cattle to dogs 74
4.1.2.1. Infection of puppies with isolated protoscolices 74 from natural infected lungs (Group 3)
4.1.2.2. Infection of puppies with isolated protoscolices 74 from Natural infected liver (Group 4)
4.1.2.3. Infection of puppies with intact hydatid cyst from 74 natural infected lungs (Group 5)
4.1.2.4. Infection of puppies with intact hydatid cyst from 75 natural infected livers (Group 6) 4. 2. The effect of temperature on the viability, survival 76 time and infectivity of hydatid cysts 4. 2.1 Testing the viability and the survival time of the 76 Protoscolices of Echinococcus granulosus in-vitro 4.2.2. Experimental transmission using protoscolices of
E. granulosus stored in the fridge at 4-10 cº 82 (in- vivo studies)
4.3. Hydatid Cyst Biology 85
4. 3.1. The Diameter and volume of hydatid cysts 85
Hydatid cysts of camels 4.3.1.1. 85
4.3.1.2. Hydatid cysts of Cattle 88
4.3.1.3. Hydatid cysts of sheep 90
4. 3. 2. Status of the cysts and cyst fluids 92 Hydatid cysts of camels 4. 3. 2.1. 94 4.3.2.1.1. Status 94
4.3.2.1.2. Cyst fluid 95 Cattle hydatid cysts 4. 3.2.2. 97
4.3.2.2.1. Status 97 Cyst fluid 4.3.2.2.2. 98 Sheep hydatid cysts 4.3.2.3. 99
4.3.2.3.1. Status 99 Cyst fluid 4.3.2.3.2. 100
4. 3. 3. The number of the protoscoleces per cyst 101
4. 3 4. Percentage of Hydatid cysts in the lungs and livers
of the slaughtered animals 101
4.3. 4.1. Camels 101
4. 3. 4.2. Cattle 102
4. 3.4. 3. Sheep 103
4.4. Records of hydatid cysts in the 105 Intermediate host
4.4.1. Record of hydatid cysts from slaughtered animals 105 in Khartoum state (1995 – 2008) Natural hydatid disease in camels 4.4.1.1. 105 Natural hydatid disease in cattle 4.4.1.2. 105
4. 4.1.3. Natural hydatid disease in sheep 105
4.4.1.4. Natural hydatid disease in goats 106
3.4.2. Recorded Cases of human hydatidosis in Khartoum 108 State, (2000- 2009)
4.4.2.1. Analysis of Recorded Cases 108
4.4.2.2. Human Reported Cases (16 Cases) 113
Chapter Five 125
Discussion and Conclusions 125
REFERENCES 140
Abstract: (In Arabic) 174
LIST OF TABLES Table Title Page 1 Current terminology of various forms of
echinococcosis and their causative agents,
including their approximate geographical range. 7 2 The Experimental Design Showing the Number of puppies experimentally infected with Hydatid cysts from different origins and organs of naturally 47 infected animals. 3 (Table Form for Data collection) Testing the Viability and the Survival time of the Protoscolices of Echinococcus granulosus In-Vitro 53 4 The Infectivity and the pre- patent period of Echinococcus granulosus in experimentally 64 infected puppies with 6000 fresh protosclices from the lungs of naturally infected camels. 5 Worm burdens and intestinal distribution (%) of Echinococcus granulosus in experimentally 66 infected puppies with 6000 protosclices from the lungs of naturally infected camels. 6 The Infectivity and the pre- patent period of Echinococcus granulosus in experimentally infected puppies with 6000 fresh protosclices
obtained from the livers of naturally infected 71 camels. 7 Descriptive Statistics: The Infectivity and the pre- 71 patent period of E. granulosus in infected puppies
with 6000 protosclices obtained from the livers of
naturally infected camels. 8 Puppies experimentally infected with protoscolices and intact Hydatid cysts of E. granulosus from 75 naturally infected cattle. 9 Viability of Protoscolices after preservation in 78 various solutions & conditions 10 Viability percentage of the Protoscolices after 79 preservation in hydatid Cysts in the fridge 11 The infectivity and pre-patent period of 83 E .granulosus in experimentally infected puppies 12 Diameter and fluid volume of hydatid cysts collected from naturally infected camels, cattle & 86 sheep 13 Fertility of Hydatid Cysts Examined 93
14 Status of hydatid cysts collected from naturally 95 Infected camels, cattle and sheep 15 Fluid Status of hydatid cysts of naturally infected 98 cattle
16 Status percentage of hydatid cyst’s fluid of sheep 100 origin 17 Mean & Std.Deviation of the protoscolices 101 numbers in camel’s hydatid cysts 18 Number of Hydatid cysts recovered from the lungs 102 and livers of slaughtered animals
19 Occurrence of hydatid cyst in slaughtered animals 106 in Khartoum State during the Period 1995 – 2008
20 Number and percentage of infection with hydatid
cysts in slaughtered camels in Albugaa abattoir 107
during the Period January - April 2009
21 Some recorded cases of Human Hydatidosis in 109 Khartoum State during the period 2000-2009.
22 Statistical analyses of Patient ages and cyst 110 measurements 23 Number and Percentage of organs infected with 111 Human Hydatid cysts
24 Number and Percentage of males and females Infected with Human Hydatid cysts 112
LIST OF PLATES
Plate Title Page
1 One group of the experimental animals 48
2 Photomicrograph showing viable invaginated protoscolices of Camel origin. 49
3 Photograph showing 12 Hydatid cysts from a lung of a camel slaughtered at Albugaa Abattoir 56
4 Hydatid cysts from infected liver and lungs of a camel slaughtered at El Salam Abattoir 57
5 Photo microscopic showing evaginated protoscoleces. 60
6 Microscopic Photograph showing scolex of
E. granulosus 68
7 Microscopic Photograph showing adult E. granulosus worm 68
8 Microscopic Photograph showing a gravid segment of E., granulosus worm obtained from experimentally infected puppy 69
9 Different sizes of Echinococcus granulosus obtained from an experimentally infected dog with protosclices 73 of naturally infected camel’s lung
List of Figures
1 The Infectivity of E. granulosus in experimentally 65 infected puppies with protoscolices from the lung of naturally infected camels
2 Percentage of intestinal distribution of E. granulosus in 67 experimentally infected puppies
3 Infectivity of hydatid cysts from the lungs and livers of 72 camels in infected puppies
4 Viability of protoscolices after preservation in various 77 solutions and conditions.
5 Viability percentage of protoscolices after preservation 81 in hydatid cysts in the fridge
6 Viability % of protoscolices after preservation in 82 hydatid cysts in the fridge
7 The Average Infectivity (%) of Storage Hydatid Cysts 84 in Experimentally Infected Puppies
8 Mean diameter of Hydatid cysts 86
9 Mean volume of Hydatid cysts examined 87
10 Volume and Percentage of camel’s hydatid cysts 88
11 Diameter (Size) and percentages of cattle’s hydatid 89 cysts
12 Volume and percentages of cattle’s hydatid cysts fluid 90
13 Diameter (Size) percentage of sheep’s hydatid cysts 91
14 Volume percentage of sheep’s hydatid cysts 92
15 Fertility of Hydatid Cysts of Camels, Cattle & Sheep 94
16 Fertility percentage of camels, cattle and sheep hydatid 95 cysts
17 Status percentage of hydatid cyst’s fluid of camels’ 96 origin
18 Status of cattle’s hydatid cysts 97
19 Fluid status of cattle's hydatid cysts 99
20 Status of hydatid cyst’s fluid from sheep origin 100
21 Hydatid cyst in lungs and livers of camels 102
22 Percentage of hydatid cysts in lungs and livers of cattle 103
23 Hydatid cyst’s percentage in lungs and livers of sheep 104
24 Hydatid Cyst Measurements of Human Reported Cases 110
25 percentage of organs infected with human hydatid cysts 111 in Khartoum state
26 Percentage of Females and Males 112
Human Hydatidosis
List of Appendices
Plate Title Page 1 Life cycle of Echinococcus granulosus 175
2 An illustration of Life cycle of Echinococcus
176 Echinococcus granulosus. Adults 3 177
4 Schematic illustration of hydatid cyst 178
5 Larval types found in the taeniid tapeworms. 179
6 Microscopic photograph showing Echinococcus 180 granulosus scolex 7 Eggs of Echinococcus granulosus 181
8. Microscopic photograph showing the morphology of Echinococcus granulosus adult worm 182
9 Hydatid cysts in a horse liver 183
10 Gross pathology of membrane and hydatid daughter cysts from a human lung. 184
11 A huge ovarian cyst arising from right ovary of a woman 185
12 Hydatid cysts being removed from the liver of a human. 186
13 Hydatid Cyst - orbit 187
14 Appearance of a typical cyst at removal 188
15 Hydatid cysts infect lungs, liver, and other internal Organs of big game animals. 189
CHAPTER ONE
INTRODUCTION
Echinococcosis/ hydatidosis are terms usually applied to the zoonotic infection caused by adult dog tapeworm Echinococcus granulosus and its larval stage, the hydatid cyst, respectively (Eckert et al., 2001).
It is one of the most important zoonotic diseases in the world. High parasite prevalence are found in the Middle East as well as Arabic North
Africa (Andersen et al., 1997; Eckert et al., 2001; Battelli et al., 2002; and .
Romig, 2003)
Echinococcus granulosus is the most important tapeworm of dog and other carnivores (Dent and Kelly, 1976). Its larval forms cause hydatidosis in domestic animals and man (Baldock et al., 1985).
This cestode belongs to the genus Echinococcus, with five species, namely: E. granulosus, E. multilocularis, E. vogeli, E. oligarthrus and E. shiquicus (Thompson and McManus, 2001; Xiao et al., 2006). These five species are morphologically different in the adult and larval forms (OIE,
2004).
Cystic echinococcosis (CE), caused by the larval stages of the tapeworm
Echinococcus granulosus, is known to be one of the most important parasite
of livestock worldwide and is the cause of the most widespread parasitic zoonoses (Craig et al., 2007; Cringoli et al., 2007).
Echinococcus granulosus is a worldwide distributed parasite
(Matossian et al., 1977). The parasite has been extensively studied in a number of different geographical areas (McManus and Smyth, 1986). Pastoral communities in developing countries with poor hygiene have been reported to be highly at risk of becoming infected with E. granulosus due to their close association with dogs (Andersen et al., 1997). The suitable climatic and ecological features, traditional situations such as large numbers of small, ill- equipped and unsupervised abattoirs, home slaughtering and big population of stray dogs, are the main factors influencing the persistence of E. granulosus
(Seimenisn et al., 2006).
This parasite causes serious public health problems and economic losses due to condemnation of affected organs.
The life cycle of Echinococcus granulosus includes dogs (and other canines) as definitive hosts and a variety of species of warm blooded vertebrates (camels, sheep, cattle, goats, wild animals and humans) as intermediate hosts. The infection is transmitted to the definitive host when hydatid cysts are ingested.
Both man and animals as intermediate hosts acquire the infection by accidental ingestion of the eggs from the environment. Contaminated foodstuffs and infected dogs carrying the tapeworm eggs in their fur are suspected to be important sources of infection to the intermediate hosts.
The adult cestode worm is very small, usually consisting of only three to four proglottids, (Urquhart et al., 1987; Eckert and Deplazes, 2004; OIE,
2004). It lives in the dog's small intestines. Eggs are liberated in the host's feces and when these eggs are ingested by the intermediate host they hatch in the host's small intestines. The eggs enter the digestive system of the intermediate host, they hatch giving oncospheres (hexacanth embryos) which penetrate the gut wall and enter the circulatory system. They can be distributed throughout the intermediate host's body (although most end up in the liver and lungs) and grow into hydatid cysts.
The hydatid cyst is a fluid –filled sac surrounded by an outer layer of fibrous tissue laid down by the host and has a characteristic laminated appearance. The cyst is lined by a germinal membrane from which brood capsules grow. Within the brood capsules, the next generations of tapeworm heads grow. Each capsule may contain up to 40 heads or protoscolices.
Brood capsules which become detached from the germinal membrane and float free within the fluid are referred to as daughter cysts. Brood capsules
release the tapeworm heads (‘hydatid sand’). If a cyst ruptures within a host, the brood capsules can form new cysts, called secondary cysts.
Humans can accidentally become intermediate hosts by ingesting the eggs of the tapeworm. While most cysts develop in the liver and lungs, other organs and tissues may become affected (Soulsby, 1982).
Under most circumstances humans form "dead end" in the life cycle, but hydatid disease in humans remains a serious problem because the disease can cause serious pathological effect.
Such parasitic diseases which are transmitted naturally from animals to man are known under the name of parasitic zoonosis.
Hydatid cysts have the ability to grow quite large. The pathology associated with hydatid disease in the intermediate host depends on the diameter of the cyst and its location. One or two small cysts in the liver of a host might stay unnoticed for years. However, a single large cyst in the liver could prove fatal. Hydatid disease is far more serious when the cysts are found in other locations, particularly the brain. Hydatidosis is the most serious human disease caused by a larval cestode.
The disease manifests chronic debilitating condition where fluid-filled cysts are formed in any part of the body. Domestic intermediate hosts (cattle, sheep, goats and camels) are major reservoirs for human cystic echinococcosis
caused by Echinococcus granulosus in the East African region (Macpherson et al., 1989).
Objectives:
1. Clarify the magnitude of hydatidosis in man and animals in Sudan.
2. Performed different experimental transmission of E. granulosus from
natural intermediate hosts to the definitive host (dogs); using various
sources of various organs of natural infected animals. Thus to study the
actual role of these infected organs of animals in maintaining and
spreading the etiogenic agents of the diseases.
3. Examine the effect of temperatures on the viability and the survival time
of the protoscolices within the cysts (in –vitro) to fine a suitable preserved
condition and materials.
4. Study the infectivity of stored viable hydatid cysts in-vivo, by performed
experimental transmission of these cysts to the dogs.
5. To study the different biological aspect of hydatid cysts obtained from
different organs of natural infected animals.
CHAPTER TWO
LITERATURRE REVIEW
2. 1. Classification
Genus: Echinococcus (Rudolphi, 1801)
At present, five species of the genus Echinococcus are recognized and regarded as taxonomically valid: E. granulosus (cystic hydatidosis) (Batsch,
1786), E. multilocularis (multivesicular hydatidosis) (Leuckart, 1863), E. oligarthrus (Diesing, 1863), E. vogeli (polycystic hydatidosis) (Rausch and
Bernstein 1972) and E. shiquicus. Until recently E. shiquicus had been discovered only in a specific region of China (OIE, 2008).
Within the species E. granulosus, genetic heterogeneity is common resulting in a number of intraspecific variations or ‘strains’. However, some of the forms which have been recognized as distinct strains were, in fact, described many years ago as subspecies. The development of the strains may be the result of the fact that tapeworms are hermaphrodites, which reproduce themselves through cross- or self-fertilization. A single mutant can therefore produce large genetically identical populations that differ from the original
genus. These populations are referred to as strains (McManus and Smyth,
1986).
Table 1. The current terminology of various forms of echinococcosis and their causative agents, including their approximate geographical range. (Pawlowski, 1997; Pawlowski et al., 2001).
Causative Term for Geographical Metacestode agent disease range
Echinococcus Cystic Cosmopolitan Unilocular granulosus echinococcosis cysts in viscera (species group) (hydatidosis)
Echinococcus Alveolar Northern Multilocular multilocularis echinococcosis hemisphere cysts in viscera
Echinococcus Polycystic Central and Polycystic vogeli echinococcosis South America cysts in Muscles
Echinococcus Polycystic Central and Polycystic oligarthrus echinococcosis South America cysts in viscera
Echinococcus _ China Unilocular shiquicus cysts in Viscera
2. 2. Morphology of Echinococcus granulosus 2.2.1. Adult
The adult worm varies between 2-7 mm in length and usually possesses two to six segments (Eckert and Deplazes, 2004; OIE, 2004). The scolex has four muscular suckers and a rostellum with two rows of large and small hooks
(Thompson and McManus, 2001); they are tightly inserted into the crypts of
Lieber-kǜhn in the gut mucosa. The rostellum contains a rostellum gland which secretes a substance, which appears to be a lipoprotein (Smyth, 1964b).
The adult worm is hermaphrodite with reproductive ducts opening at a common, lateral pore, the position of which may vary depending on the species and the strains. There is a prominent cirrus sac, which may be horizontal or tilted interiorly and the vitellarium is globular. The uterus dilates after fertilization, eventually occupying most of the gravid segment when the eggs are fully developed (Thompson and McManus, 2001).
2.2.2. Eggs
The eggs closely resemble those of other Taenia species found in dogs from which they were considered to be morphologically indistinguishable
(Eckert et al., 2003). But this problem has been solved by Craig et al.,
(1986) with the development of a specific Echinococcus anti–oncospheral monoclonal antibody, which specifically identifies Echinococcus eggs.
Eggs are ovoid (30 - 40 um) each consisting of keratinised embryophore which gives the egg a dark striated appearance.
2.2.3. Hydatid cysts (metacestode)
The metacestode basically consists of a bladder with an outer cellular laminated layer and an inner nucleated germinal layer, which may give rise by asexual budding to brood capsules. Protoscoleces arise from the inner wall of the brood capsules. There are some differences in the structure and development of the metacestode of the five species of Echinococcus
(Thompson and McManus, 2001).
The metacestode of Echinococcus granulosus
It is a fluid – filled bladder usually unilocular but communicating chambers also occur (Thompson, 1995). The cyst consists of an inner germinal or nucleated layer supported externally by a tough, elastic, cellular laminated layer of variable thickness and surrounded by a host –produced fibrous adventitial layer (Thompson and McManus, 2001).
Growth is expansive and endogenous daughter cysts may be produced.
Occasionally, individual bladder may reach up to 30 cm. in diameter. The metacestodes cause hydatid disease in man and animal (D’Alessandro et al.,
1979; Thompson, 1977; Thompson and Smyth, 1975; Verster, 1965;
Thompson and McManus, 2001).
The cyst wall
The cyst wall of the metacestode consists of three layers, an inner germinal or nucleated layer, laminated layer and the host - producing fibrous layer:
The germinal or nucleated layer
This layer is of parasitic origin. It is divided into three regions, the tegument, the tegument cell region and the innermost area bordering the cyst cavity (Lascano et al., 1975).The inner germinal membrane produces brood capsules and on the inner wall of the brood capsules, by the asexual budding process, thousands of protoscoleces may be formed within a single cyst.
The laminated layer
The middle (laminated) layer is unique to the genus Echinococcus in comparison with other larvae of cestodes. The laminated layer is the outermost region of the cyst and provides a degree of both mechanical and immunological protection for the germinal layer by forming a barrier against
cellular attack (Rickard and Williams 1982; Dixon and Jenkins 1995). This layer is not, however, a barrier to the antibody as immunoglobulins have been detected within the cyst fluid in some host species (Edwards, 1982).
The layer is absent in young cysts until they are about 14-18 days old. This layer is a cellular, polysaccharide protein complex that stains strongly by periodic acid, which provides a useful diagnostic marker in histological studies (Kilejian et al., 1962; Craig et al., 1995). It is originated by the germinal (inner) layer (Bortoletti and Ferretti, 1978; Holcman et al., 1994).
Host material may also contribute to its structure ( Taherkhani et al.,
2005; Kilejian and Schwabe, 1971; Pezzella et al., 1984).
The hydatid cyst fluid
The hydatid cyst fluid is a complex mixture of molecules derived from the parasite and the host. It contains proteins, glucose, uric acid, minerals (Sodium, Potassium, Calcium and chloride) and trace elements
(Radfar and Iranyar, 2004).
The quantitative differences in the biochemical composition of hydatid fluids reflect strain variation in different intermediate hosts (McManus and
Macphereson, 1984). Moreover differences are shown in the development of the same strain of E. granulosus in different organs of the intermediate host species. Cyst fertility status can also cause shifts in the metabolism essential
for parasite survival in different environments (Thompson and Lumbery,
1995).
Radfar and Iranyar (2004) made a comparative study on the biochemical parameters in hydatid cyst fluids of Echinococcus granulosus in sheep, goats, camels, cattle and humans in Iran. They found quantitative variations in the levels of glucose, calcium and creatinine in the fluids of camels from others.
These differences were statistically significant. The biochemical composition in hydatid cyst fluids of sheep, goats, cattle and humans were similar. Kadir
(2006) reported a higher calcium concentration in cyst fluid in camels than in cattle and goats, but lower than that of sheep origin.
2. 3. General Life – Cycle
The life cycle Echinococcus involves two mammalian hosts. The adult cestode inhabits the small intestines of a carnivore (definitive host), feeds on intestinal contents and does not invade tissues. Therefore, even heavy infections with several thousand worms usually remain asymptomatic. The parasite produces eggs containing infective oncospheres. After oral uptake of eggs by an intermediate host, a larval stage, the metacestode, develops in the internal organs.
2.3.1. Definitive host
The adult cestode inhabits the small intestines of domestic and wild canids (definitive hosts) and produces eggs containing infective oncospheres.
Either cestode segments (proglottids) containing eggs or free eggs are released from the intestinal tract of the carnivore into the environment.
2.3.2. Eggs in the environment
The eggs are highly resistant to physical factors and can remain infective for long periods in suitable environmental factors. The eggs can stay infective for many months or up to about one year in a moist environment at lower ranges of temperatures (+4º to 15º C). Eggs of Echinococcus are sensitive to desiccate. At a relative humidity of 25%, the eggs of E. granulosus are killed within 4 days. Heating to 60º to 80 º C destroys the eggs of E. granulosus in less than 5 min. On the other hand, Echinococcus eggs can survive freezing temperatures (Gemmell and Roberts, 1998; Gemmell and
Lawson, 1986; Veit et al., 1995).
The agents which are responsible for egg dispersion into the environment have not yet been fully identified, but the suggested agents include rainfall, wind, birds, arthropods, earthworms and animal feeds
(Gemmell, 1997).
Paula et al. (2005), studied the viability and infectiousness of aged eggs of Echinococcus granulosus by in -vivo evaluation in sheep. They demonstrated that after 41 months of ageing of the eggs under environmental conditions of an inferior arid climate the eggs were still able to produce infection in sheep infected with 1200 eggs per animal. In sheep experimentally infected with these aged eggs, the occurrence of hepatic and pulmonary cysts was determined when they are examined after necropsy.
2.3.3. Intermediate and accidental hosts
A wide range of mammals (including man) acquire the infection by ingestion of eggs. Following the action of enzymes in the stomach and small intestines, the oncosphere is released from the keratinized embryophore
(Thompson, 1995). Bile assists in activating the oncosphere, which penetrates the wall of the small intestines. Penetration is then aided by the hook movements and possibly by secretions, of the oncosphere .Upon gaining access to a venule or the lacteal, the oncosphere is passively transported to the liver, lungs and a few may be transported to the kidneys, spleen, muscles, brain or other organs (Thompson, 1995). There, the metacestode grows eventually forming fluid-filled cysts or vesicles. Formation of protoscolices within the metacestode takes place. Typically, the mature metacestode
produces numerous protoscolices and when eaten by the definitive host grows into adult tapeworms (Macpherson, 1985). Accidentally, eggs are also ingested by humans and other “aberrant” hosts that do not play a role in the natural cycle (Thompson et al., 2001). On rare occasions, the spectrum of aberrant hosts may even include definitive hosts (dogs). Whereas the infection of carnivores with immature or mature intestinal stages of E. granulosus does not cause morbidity, the invasion of various organs (mainly liver and lungs) of intermediate or aberrant hosts by metacestodes can cause severe and even fatal disease ( Eckert and Deplazes, 2004).
2.3.4. The metacestode stage
Once the oncosphere has reached its final location, it develops into the metacestode stage. The metacestodes typically grow as large, fluid filled cysts
(‘hydatid’) that are located in various organs of their hosts, most frequently in the liver or lungs. Within the cysts large numbers of small ‘brood capsules’ are formed, which contain protoscolices and usually float free in the cyst fluid
(‘hydatid sand’). In some cases, secondary cysts (‘daughter cysts’) or septa are formed in the primary cyst. The role of the large amount of fluid in the cysts is unexplained, but observations suggest that it may serve as an attractant to the definitive hosts, encouraging them to devour the parasitic cyst
before feeding on other parts of the prey (Thomas, 2003). Time of development is variable and it may take several months before protoscoleces are produced (fertile metacestode). There may be several thousand protoscoleces within a single cyst of E. granulosus. Each single protoscolex is capable of developing into a sexually mature adult worm. Not all metacestodes produce protoscoleces (sterile metacestode). When protoscoleces are ingested by a suitable definitive host, following the action of pepsin in the stomach, they evaginate in the upper duodenum in response to a change in pH, exposure to bile and to an increase in temperature. They then develop to sexually mature adult tapeworm in about 6-8 weeks after infection depending on the species, strain and on the susceptibility of the host
(Thompson et al., 2001).
2.4. Host Range of Echinococcus granulosus
Echinococcus granulosus has the least intermediate host – specificity of any of the five species of the genus and this contributes to its cosmopolitan distribution. The larval forms have been found in domestic and wild ungulates
(sylvatic cycle) belonging to eight families, particularly bovids as well as primates, leporids and macropod marsupials (Thompson et al., 1995;
Thompson, 1979; Thompson and Allsopp, 1988).
The domestic dog (Canis familiaris) is the principal definitive host of E. granulosus, but in certain regions wild canids may be involved in the life cycle of the parasite, as example wolves and moose in North America,
(Rausch, 1952). Lions have also been recorded as definitive hosts of E. granulosus in Africa, the only record for felids, (Thompson et al., 2001).
Jackals and deer in Ceylon (Paramananthan and Dissanaike, 1961) and jackals and wild ruminants in Kenya are involved in predator –prey relationships, which support wildlife echinococcosis (Eugster, 1978).
Although E. granulosus penetrates deep between the villi of the small intestines of a definitive host; there are no pathogenic effects even in animals with heavy infection (Eckert et al., 2001). Therefore, infected definitive hosts are typically asymptomatic carriers of the parasite.
2.5. Variations in Echinococcus granulosus
Thompson and Lymbery (1990) showed different variety of morphological features and life – cycle characters. These variations evolved through characterization of the nuclear and mitochondrial genomes of Echinococcus granulosus representative isolated strains (Bowles et al., 1992; Bowles and
McManus, 1993a and b). A new data based on genome patterns, supported previous characterization that are based on the morphological and biological
criteria. A number of well characterized strains of E. granulosus are recognized which appear to be adapted to particular life –cycle patterns and host assemblages. These are sheep strain of the parasite (G1) using sheep, cattle, pigs, camels, goats and man as intermediate hosts and dogs and foxes as final hosts. Tasmanian sheep strain (G2), is slightly different from the common sheep strain. Buffalo strain (G3), the cysts of which occur mainly in cattle and buffalo in Srilanka and India. Horse strain (G4) occurs in horses and other equines, Cattle strain (G5) occurs in cattle in Central European countries, Russia, South Africa India Sir Lanka and Argentina. The camel strain (G6) has limited intermediate hosts, namely camel and goats while man and cattle are unclear to be intermediate hosts. It is distributed in the Middle
East, Africa, China and Argentina (Thompson, 1995). Pig strain (G7) occurs in pigs, wild boars, beavers, cattle and humans. Cervid strain (G8), occurs in the ungulates of the family Cervidae (elk, red deer, reindeer) (Rausch, 1995).
Lion strain (G9), the adult worms have been found in wild canids and lions.
The metacestodes occur in many species of wild ungulates (Rausch, 1995).
Fennoscandien cervid strain (G10), (Lavikainen et al., 2003) occurs in wolfs and the intermediate hosts are wild cervids and reindeer in Finland.
2. 6. Epidemiological significance of Echinococcus granulosus strains
Variations in the pathogenicity of the strains and species of
Echinococcus will influence the prognosis in patients with echinococcosis
(Thompson and McManus, 2001).
It has to be emphasized that at least seven of E. granulosus genotypes are infective to humans.
Globally, most human cases of CE are caused by the sheep strain (G1) of
E. granulosus. Information on the infectivity of the lion strain and the buffalo strain is not available. Currently, there is no evidence that the horse strain is infective to humans (Thompson, 1995; Eckert and Thompson, 1997;
Thompson and McManus, 2002). This strain is widespread and common in
Ireland, but up-to- date original cases of human CE have not been observed.
The camel strain has recently been identified in human CE cases in Argentina,
Nepal and Iran (Fasihi Harandi et al., 2002; Rosenzvit et al., 1999; Thompson and McManus, 2002). In Sudan , cattle strain (G5) occurs less frequently in cattle and sheep strain (G1) is currently absent in central Sudan (Elmahdi et al., 2004). Camel strain was reported to be the most prevalent strain in
Sudan (Omer et al., 2004; Osman et al., 2007). It was found that Sudanese
breeds of sheep and goats are known to harbor calcified hydatid cysts (Saad and Magzoub, 1989b).
According to Thompson & McManus (2002) and Le et al. (2002), special features revealed by genetic comparisons and phylogenetic analyses would justify recognition of the horse and the cattle strains of E. granulosus as separate species, namely, E. equinus and E. ortleppi, respectively.
2. 7. Viability of E .granulosus protoscolices at different conditions
Ali et al., (2007) reported that the longest survival time of E. granulosus protoscolices was 3 days at −10 °C (50% RH), 36 days at 0 °C
(60% RH), 28 days at 10 °C (65% RH), 12 days at 20 °C (70% RH), 4 days at
30 °C (75% RH) and 3 days at 40 °C (80% RH). Protoscolices lost their viability rapidly at the extreme temperatures (−10 and 40 °C) tested. They determined the viability of the protoscolices by Eosin exclusion test (Himonas et al., 1994). Protoscolices stained with eosin were counted as nonviable and the protoscolices, which had not been stained, were counted as viable.
Andersen and Loveless, (1978) carried out a study to determine the effects of storage at constant temperatures upon the survival of protoscolices of
Echinococcus granulosus from hydatid cysts removed from infected sheep.
Parallel tests were conducted on intact cysts from both lung and liver and on protoscolices stored in hydatid fluid. The viabilities of protoscolices in hydatid cysts of sheep origin are as follows: 18% in 1 h at −20 °C, 61% in 4 h at −10 °C, 55% in 16 days at 1 °C, 22% in 16 days at 10 °C, 98% in 8 days at
20 °C, 67% in 2 days at 30 °C, 48% in 16 h at 40 °C and 61% in 2 h at 50 °C.
Generally they concluded that protoscolices survived considerably better when stored within intact cysts than when stored in 1 ml of hydatid fluid. At temperature ranges where putrefaction occurred, protoscolices in cysts from the lung survived longer than those from the liver.
2. 8. Geographical Distribution and Prevalence
Due to the lack of representative and well documented data from many countries, only an incomplete and preliminary picture of the geographical distribution of Echinococcosis can be provided (Eckert et al., 2001).
The incidence of the disease is particularly high in rural areas, where there is increased contact between man and dog. Human cystic echinococcosis is often considered an occupational public health problem for sheep farmers, ranchers and shepherds in endemic areas (Cohen et al., 1997).
E. granulosus is the species most widely distributed throughout the world and occurs in all continents including circumpolar, temperate, subtropical and tropical zones (Craig et al, 1996; Eckert et al., 2001; FAO, 1982). It causes serious public health problems in certain parts of the world (Schantz, 1990).
The wide variety of animal species that can act as intermediate hosts and the domestication and spread of some of these animals from Europe to other parts of the world have given the parasite a worldwide distribution. High parasite prevalence is found in the Mediterranean region, Russia, China, Africa
(northern and eastern) and South America (Eckert et al., 2001; Menghebat et al., 1993; McManus and Smyth, 1986). It is also common in parts of the
United Kingdom, Europe and Australia (Cook, 1989; Schantz, 1990,
Arambulo, 1997; Eckert et al., 2000; Lightowlers et al., 2000).
In some European countries the annual incidence (IA) rates of hospital cases of cystic echinococcosis (CE) vary between <1.0 and > 8.0 per 100,000 populations. In China, the average hospital cases were 8.7 per 100,000 in
1990. High incidence rates or prevalence have also been recorded from countries in northern and eastern Africa (prevalence up to >3%) and in South
America (example: Uruguay) of 6.5 per 100,000 populations in 1997. A few islands are free of E. granulosus (Iceland, Greenland) or “temporary free” as
New Zealand, Tasmania and southern Cyprus. Hydatid cysts were recovered to be 35.2% of camels in Iran. The organ distribution of cysts was 49.4% in lungs alone, 30.0% in both liver and lungs, 14.6% in liver only and 6.0% in other organs. Therefore, the lungs were the predominant sites of the hydatid cyst. The range in the number of cysts was 1-48 in infected animals. There was a direct relationship between the rate and intensity of infection and host age. The fertility rate of lung cysts (69.7%) was higher than that of liver cysts
(58.7%) and other organs (50.0%), while the viability rate of protoscoleces of liver fertile cysts (80.3%) was significantly higher than that of lung cysts
(55.8%) and other organs (57.1%) (Ahmadi, 2005).
In Hadhramout, Yemen, the prevalence was 3.21% in sheep and 2.13% in goats (Baswaid, 2007). All the positive animals were males. The liver was the predominant site of infection in both animals. In relation to the age-group
(years) the rate of infection increased with the animal's age. There was a slight difference in the fertility of the cysts in sheep (46.6%) and goats
(55.2%), while the same observations were noted between liver and lungs in the two animals.
2.9. Echinococcus granulosus in Africa
Echinococcus granulosus has been recorded from most of the African countries. Several reviews of the epidemiological situation were published between 1997 and 1997(Andersen et al, 1997; Craig et al, 1996; Schantz et al, 1995).
2.9.1. North African countries
Previous and recent reports described the endemic occurrence of E. granulosus in dogs and livestock and human cases of CE in the North African countries bordering the Mediterranean Sea, including Morocco, Algeria,
Tunisia, Libya and Egypt (Ibrahim and Gusbi, 1997; Kachani et al., 1997;
Ouhelli et al., 1997; Shambesh, 1997).
In Tunis Lahmer et al., ( 2009), found that , most of hydatidosis patients,
(56%), were originated from rural areas and (93.3%) of the cysts were fertile, with a mean protoscolex viability of 21.8%. Protoscolex viability was low in the cysts that appeared to be solid calcified masses. The study also showed that all cysts investigated were caused by E. granulosus of the G1 genotype.
Haridy et al, (1998) studied hydatidosis in slaughtered camels in Egypt.
He found that the overall annual prevalence rates of camel infection with hydatidosis were 5.5% (1992), 6.1% (1993), 6.7% (1994), 8.2% (1995) and
4.3% (1996). The most predicted site of infection was the lung followed by the liver. Cystic infections in other organs were rarely seen. The fertility of the cysts was 29% and 20% in the lung and the liver respectively.
In an abattoir study, in different areas of northern Libya, the overall prevalence of infection with hydatidosis was 48% in camels, 15.8% in sheep and 3.8% in goats. The infection rates, number and diameter of the cysts were significantly higher in older camels. In camels, the lungs were the most frequently infected organs (85.4%) with liver cysts occurring at a significantly lower rate (33%). In contrast, the liver was the predominant infected site with prevalence values of 86% and 100% in sheep and goats, respectively. More than 90% of camel hydatid cysts were fertile (Ibrahim and Craig ,1998).
2.9.2. Sub- Saharan Africa
Echinococcus granulosus has been recorded from most of the sub –
Saharan countries over a vast area stretching from the Sahel zone to southern
Africa (Eckert et al, 2001).
2.10. Human Cystic Echinococcosis
Studies in different parts of sub-Saharan Africa have shown varied distribution of CE. of hospital records (Macpherson et al., 2004) among the
Karamojong community in western Uganda has shown an average of 20
surgical cases of CE per year reported in each of the hospitals in Karamojang and Mbarara. These findings indicate that CE is a public health and an economic problem in Uganda (Macpherson et al., 2004). In Turkana, the prevalence of CE in humans is about 2.5% (Buishi, 2006).
2.11. Cystic Echinococcosis in Livestock
Most data on the current status of E. granulosus in sub-Saharan African are derived from slaughter records of infected animals. In Sudan, high prevalence of CE has been reported in all domestic livestock species. The disease has been reported to have a prevalence of 45% in camels, 3% in cattle and 7% in sheep ( Elmahdi et al., 2004) . In Ethiopia CE in livestock is highly endemic in the southern part of the country. Mersie (1993), found
20.5% of cattle and 22% of dogs were infected in eastern Ethiopia.
A study in Tanzania showed that 48% of cattle, 34.7% of goats, 63.8% of sheep and 10% of dogs were infected with E. granulosus (Ernest et al.,2004).
In Turkana, Kenya, Njoroge et al., ( 2000), found that out of 1390 goats examined, from Turkana, 1.8% were infected with hydatid cysts. These surveys show that CE is highly endemic and a major public health problem in eastern Africa.
2.12. Factors associated with persistence, emergence, or reemergence
The factors associated with persistence, emergence, or reemergence of
CE have been described in Bulgaria (Todorov and Boeva. 1999) and the
Mediterranean region (Battelli et al., 2002). They included: (I) the presence of large numbers of dogs (especially stray dogs) infected with E. granulosus
(II) easy access of dogs to organs of livestock infected with E. granulosus cysts (III) insufficient facilities for slaughter and destruction of infected viscera (IV) illegal or undisputed home slaughter (V) close association of dogs and other animals on small rural lots of land (VI) uncontrolled animal trade and movements within and between countries (VII) poor living conditions (especially lack of tap water) (VIII) lack of health education (IX) economic instability and financial restrictions in control and prevention.
2.13. Cystic Echinococcosis in Humans
2.13. 1. The Course of infection
CE is caused by the metacestode stage of various strains of E. granulosus, which is a cystic structure typically filled with a clear fluid
(hydatid fluid). About 5 days after ingestion of eggs, the metacestode is a small vesicle (60 to 70 µm in diameter) consisting of an internal cellular layer
(germinal layer) and an outer cellular, laminated layer. This cyst gradually expands and induces a granulomatous host reaction, followed by a fibrous
tissue reaction and the formation of a connective tissue layer. The diameter of the cysts in the human body is highly variable and usually ranges between
1 and 15 cm, but much larger cysts (>20 cm in diameter) may also occur
(Ammann and Eckert, 1996; Shambesh, 1997).
The exact time required for the development of protoscoleces within cysts in the human host is not known, but is thought to be more than 10 months post infection. Protoscoleces can already be formed in cysts of 5 to 20 mm in diameter (Pawlowski et al., 2001), on the other hand, a proportion of cysts do not produce protoscoleces and remain “sterile.” Most of the cysts are unilocular, but in some of them, smaller daughter cysts are formed within larger mother cysts. Mixed infections with metacestodes of E. granulosus and
E. multilocularis are rare, although the two species occur simultaneously in large areas of endemic infection (Pawlowski et al., 2001).
In the human host, cysts may develop in many sites following oral ingestion of E. granulosus eggs. This form of echinococcosis is known as primary CE. Secondary CE, predominantly in the abdominal cavity, results from spontaneous or trauma-induced cyst rupture and the release of protoscoleces and/or small cysts, which can grow to larger cysts.
Approximately 40 to 80% of patients with primary CE have single-organ
involvement and harbor a solitary cyst (Ammann and Eckert, 1996;
Pawlowski et al., 2001).
A literature review of 9970 patients (originating from regions in South
America, Africa, Europe and Australasia where sheep strain is common and infection is endemic) revealed that the average liver-to-lung infection ratio was 5:1 (Larrieu and Frider, 2001) A different situation exists in infected but asymptomatic individuals. Ultrasonographic and chest X-ray surveys of approximately 10,000 apparently healthy individuals living in areas of
Argentina and Uruguay with endemic infection revealed liver-to-lung ratios of 6:1 and 12:1, respectively (Larrieu and Frider,2001)). An explanation for the shift from the higher liver-to-lung ratios in asymptomatic individuals to lower values in hospitalized patients is that lung cysts cause more morbidity than hepatic cysts (Larrieu and Frider, 2001).
The initial phase of the primary infection is always asymptomatic. Small, well encapsulated, calcified cysts typically do not induce major pathology and the patients may remain asymptomatic for years or permanently (Ammann and Eckert, 1996; Shambesh, 1997).
The induction of morbidity depends on the number, diameter and developmental status of the cyst(s) (active or inactive), the involved organ, the localization of the cyst(s) within the organ, the pressure of cysts on
surrounding tissues and structures and the defense mechanisms of the infected individual. Ultrasonographic studies in South America have shown that the average diameter of cysts in asymptomatic carriers was significantly smaller
(approximately 4 cm) than that in symptomatic patients (approximately 10 cm) (Larrieu and Frider, 2001).
According to Perdomo et al., (1997), approximately 88% of the cysts detectable in asymptomatic carriers were < 7.5 cm in diameter. An ultrasonographic survey in Italy revealed that 60% of 424 individuals with CE were asymptomatic (Caremani et al., 1993).
Cyst growth is generally slow. In 14 asymptomatic cyst carriers in
Argentina, the diameter of liver cysts increased by < 3 to 4 cm in 6 patients and showed no modification in 8 individuals during a 10- to 12-year observation period (Frider et al., 1999.) Low growth rates were also reported for hepatic cysts in another study of asymptomatic patients (Larrieu and
Frider, 2001). There is evidence that liver cysts grow at a lower rate than lung cysts (Larrieu and Frider, 2001). However, the growth rates of cysts may vary between cysts in the same organ or in the same individual and between individuals in various regions. For example, in the Turkana district of Kenya, a region of high endemicity where CE caused high morbidity, higher growth rates of cysts were recorded. In an ultrasonography study of 66 patients, about
30% of the abdominal cysts grew slowly (1 to 5 mm per year), 43% showed moderate expansion (6 to 15 mm per year), 11% exhibited a more rapid increase (average of 31 mm and maximum of 160 mm per year) and 16% of the cysts did not expand or collapsed (Romig, 1990; Romig et al., 1986).
Clinical signs may occur after a highly variable incubation period of several months or years. Frider et al., (1999), observed that 21 (75%) of 28 carriers of liver cysts in Argentina remained asymptomatic during follow-up periods of 10 to 12 years after the initial diagnosis. Cysts may rupture into the peritoneal cavity, causing anaphylaxis or secondary CE. Abscess formation is possible after bacterial infection of cysts. Chronic cough and lung abscess are selected symptoms caused by pulmonary cysts and neurological disorders can be induced by cysts in the brain (Ammann and Eckert, 1996; Pawlowski et al., 2001).
Cystic echinococcosis occurs in age groups from younger than 1 to over
75 years. In some areas of endemic infection, most hospital cases were recorded in the age groups between 21 and 40 years, but the highest morbidity may also occur in younger individuals aged between 6 and 20 years
(Ammann and Eckert, 1996; Pawlowski et al., 2001).
2.13. 2. Human hydatidosis in Africa and the Sudan
Several ultrasound surveys have confirmed high prevalence of CE in humans in certain population groups and areas. In 1985-1987, a large study was performed in semi- desert regions of 4 countries (Sudan, Ethiopia, Kenya and Tanzania) involving 18,565 persons of various ethnic groups. The average prevalence of CE was 1.8% with a range between 0 and 5.6 in various regions and population groups (Macpherson et al., 1989).
High prevalence rats were also observed in north-eastern Turkana in
Kenya: approximately 7.5% before (1983) and 3.1% 10 years (1992) after the initiation of control measures (Macpherson and Wachira, 1997). In the year,
1996, 3224 persons were screened in southern Ethiopia and 16 (0.5%) were positive for CE (Magambo et al., 1996).
In Mauritania, the annual incidence of CE was estimated to be 1.2 per
100,000 populations for the period 1996-1997, based on the number of cases diagnosed at the National Hospital in Nouakchott (Beurdeley et al., 1997).
Human hydatidosis in the Sudan was firstly reported in 1909 by
Christopherson (Saad, 1985). He found 6 cases during his 7 years service in the
Sudan. Eisa et al., (1962) showed that several operations for removal of hydatid cysts were performed at Kapoeta and Torit hospitals. Cahill et al.,
(1965) carried out serological study in southern Sudan. They reported 13.1%
positive cases. Ower and Bitttakarmine, (1975) considered that about half of the human cases of the disease in Uganda, were immigrants from Southern
Sudan.
The prevalence rates of human population in Khartoum were 1.2 % (Tola,
1987). Macpherson et al., (1989b) reported prevalence between 0.5 % and
3.5% in human hydatidosis in Southern Sudan.
Njoroge et al., (2001) carried out a survey of cystic echinococcosis in southern Sudan. It involved ultrasound examination of the human population; interviews of humans and post mortem examination of stray dogs, 52.6% were females while 48.4% were males. Cystic echinococcosis was found in
2% of the human population. The proportion of people with cystic echinococcosis was higher in females (66.7%) than in males (33.3%). A total of 193 E. granulosus cysts were visualised in the people with cystic echinococcosis. The distribution of the cysts was in the liver (115), kidney
(19), abdominal viscera (44), spleen (11) and other organs (4). Sixty seven percent of the cysts were determined to be viable while 32.1% were non- viable. The study indicated that prevalence of cystic echinococcosis in
Southern Sudan may be higher than in other parts of the world where the disease had been reported and concerted effort is required to control the disease.
2. 14. Research done in the Sudan.
Echinococcosis studies in the Sudan were carried out by many researchers.
In the check list of helminth parasites of domesticated animals in Sudan
Abdel Maleck (1959) reported Echinococcus granulosus in dogs at Khartoum and Kosti with hydatidosis in Kosti in cattle and camels and in camels in
Khartoum and Omdurman. At Southern Sudan Eisa et al., (1962) reported
89.5% prevalence rate of Echinococcus granulosus in dogs in Kopoeta,
26.6% in Torit. They reported hydatidosis of 25%, 19.4% and 33.3% in cattle, sheep and goats respectively, in Equatoria and Upper Nile provinces. El
Khawad et al., (1976) reported that the prevalence rates were 6.2%in cattle and 9.3%in goats in Equatoria Province and 7.6% in cattle in Bahr - el-
Ghazal.
In Khartoum Eisa et al., (1977) recorded the prevalence rates of echinococcosis in dogs to be 6.06% with 34-3200 worms per animal. In dogs
El Khawad et al., (1979) reported the prevalence rate of 3.03 % in
Omdurman. While it were 17.51 in Khartoum province when reported by
Idris (1985). In Omdurman slaughterhouse, El sawi, (1994) found that 8.9% of sheep and 4.2% of goats were infected with hydatid cyst. It was 43.9% in
camels when examined by El Sawi and Saad, (1995). Elmahdi, (2003) reported that 45%of camels examined in Omdurman, Tampool and Madani were infected with hydatid cysts. It was 7% in sheep and 3% in cattle.
Magzoub and Saad (1986) reported 51% prevalence rate of infection among stray dogs in tampool. Tola, (1987) recorded prevalence of 56.4% in camels,
2.1 % in cattle and 2.0% in sheep in Butana, Khartoum and in Sudanese camels that were exported to Egypt.
In Kassala slaughterhouses Elansary and Hamad (1997) reported that
30.5% of the sheep examined were infected. They recorded high fertility rate
(26.2%) of the cysts encountered.
In central region El Khawad et al., (1979) reported that 35.3% of camels,
8.16% of sheep, 4.28% of cattle and 3.17% of goats were infected. Elmahdi et al., (2004), collected information on cystic echinococcosis in livestock
(camels, cattle and sheep), the data were collected in abattoir-based surveys in the towns of Omdurman, Tamboul and Wad Madani. The prevalence of infection was 44.6% in the camels, 6.9% in sheep and 3.0% in cattle. Cysts collected from cattle and camels were found more likely to be fertile (22% and 24%, respectively) than those from sheep (1%). Camels and cattle therefore appear to be the principal intermediate hosts for Echinococcus
granulosus in central Sudan, whereas sheep apparently play a marginal role in transmission.
In El Obied Saad et al., (1989) recorded 67.7% prevalence rate in camels.
In Nyala Mohamed and Elmalik (2000) reported prevalence rate 79.5% of
Hydatidosis in camels,6.4% in cattle and 26.9% of echinococcosis in stray dogs. While Mohamed and Elmalik (2004), found natural infection of 61.4% in camels, 10.9% in sheep, 5.2% in cattle, 1.6% in goats and 19.2% of echinococcosis in stray dogs and 0.0% in foxes. The fertility rates were 73.8% in camels and 27.5%in cattle.
In Eldamer Province Elhussien and Ali (1990) found that 37% of the examined camels were infected.
In a survey of hydatidosis in areas representing all regions except the south, Magzoub and M.B. Saad, (1989a and 1989b) reported that the prevalence rate of the infection was 48.7% in camels, 3.8% in cattle, 12.9% in sheep and 4.4% in goats. They observed that the fertility rate of the hydatid cysts collected were 42.4% in camels and 29% in cattle. All cysts encountered in sheep and goats with the exception of two, were calcified or semi-calcified.
A structured questionnaire followed by a focus group discussion revealed that only 7% of the respondents associated cystic echinococcosis with close contact to dogs. Examination of 24 stray dogs showed the prevalence of cystic
echinococcosis in dogs to be 54.2%. The study indicated that prevalence of cystic echinococcosis in Southern Sudan may be higher than in other parts of the world where the disease has been reported and concerted effort is required to control the disease (Njoroge et al. 2001).
2.15. Animal host and transmission cycle of Echinococcus granulosus
Previous reports indicated wide variations in the prevalence of E. granulosus in dogs and / or livestock populations in various countries and regions. Areas of high endemicity are known to occur in eastern Africa, including at least parts of Sudan, Ethiopia, Kenya and Uganda (Craig et al.,
1996; Macpherson and Wachira, 1997). Large parts of western, central and southern Africa apparently have lower prevalence but an accurate assessment is difficult due to the lack of recent and more comprehensive data (Eckert et al., 2001).
The parasite is transmitted predominantly in a domestic cycle involving dogs (large dog’s populations and many stray dogs) and various livestock animals (sheep, goats, cattle and camels). Older and more recent studies have shown high prevalence of E. granulosus both in dog populations and in one or more livestock species in various countries and regions (Eckert et al.,
2001). Wild carnivores can be hosts of E. granulosus (Macpherson and
Wachira. 1997; Schantz et al., 1995).
Two strains of E. granulosus known to occur widely in North Africa are sheep strain and camel strain (Macpherson and Wachira, 1997).
In all countries where camels have been reported as intermediated hosts, it is considered to be important for the local maintenance of the life –cycle
(Schantz et al., 1995). Ibrahim and Gusbi, (1997) reported that camels are important intermediate hosts in all North African countries and sheep, goats and cattle play a secondary role in the propagation and distribution of E. granulosus.
Epidemiological and molecular studies were conducted to investigate the role of cattle in the transmission of cystic echinococcosis (CE) in
Southern Italy, 10.4% of the examined cattle were found infected. The cysts were either sterile (42.7%) calcified or caseous (57.3%); no fertile cysts were found. The findings reported in these studies showed that CE is widespread between cattle bred in the Southern Italy. However, the absence of fertile cysts suggests that cattle would not have any role in the persistence of this important zoonosis but rather have a role as indicators of CE infection in this endemic area (Rinaldi et al., 2008).
Macpherson et al., (1985), could not establish the infection from cattle to dogs in his research carried in Kenya
Many factors as human behavior, environmental contamination livestock management, numbers of stray dog population and slaughtering practices, influence the prevalence of hydatidosis in livestock in different areas.
Slaughtering of animals without meat inspection and the feeding of hydatid organs to dogs and other socio-cultural factors help to maintain highly infected dog populations (Ibrahim and Gusbi, 1997).
2.16. Diagnosis
2.16. 1. In the definitive host:
The diagnosis of intestinal E. granulosus infection in living dogs is difficult because the small proglottids spontaneously discharged with feces are usually overlooked and eggs detected by routine microscopic techniques cannot be differentiated by light microscopy from the eggs of other
Echinococcus species or of Taenia species.
In positive cases confirmation diagnosis for the worms must be demonstrated by the routine purgation of dogs with arecoline hydrobromide. Evacuated faeces is examined microscopically directly or by flotation, sieving or sedimentation technique (Gemmell and Varela-Diaz, 1980)
The most accurate indicator of the prevalence of adult E. granulosus in dogs is the necropsy of the small intestines. Several methods have been used in the examination of the intestines of carnivores (Eugster, 1978).
Enzyme linked immunosorbent assays (ELISA) for detecting parasite antigens in fecal samples (coproantigens) have been used in specialized laboratories for the last few years (Craig et al., 1995).
The coproantigen ELISA has a reasonable sensitivity and a high specificity and can be used as a screening test for individual dogs or for dog populations.
One of the advantages of this test is that about 200 samples can be examined by one person per day (Deplazes et al., 2003).
A PCR for specific detection of DNA from E. granulosus eggs has been developed (Varcasia et al. 2004). More accurate PCR can be used as a highly sensitive and specific secondary test for confirming or excluding the E. granulosus infection.
Postmortem examination of definitive hosts for Echinococcus species requires special techniques (Eckert et al., 2001).
2.16. 2. Diagnosis in the intermediate hosts
Infections with E. granulosus cysts in intermediate hosts (sheep, goat, cattle, horses, etc.) are typically asymptomatic, except a few cases of long- standing and heavy infections. There are no reliable methods for the routine diagnosis of the infection in living animals, but in rare cases cysts have been identified by ultrasonography alone or in conjunction with serum antibody detection (Eckert et al., 2001)
A new ELISA with a high specificity and a sensitivity of 50 to 60% might be useful for detecting E. granulosus cysts in sheep on a flock basis but cannot be used for reliable diagnosis of infected individual animals
(Kittelberger et al., 2002).
2. 16. 3. Diagnosis in Human
The diagnosis of hydatidosis in humans is based on clinical, radiological microscopic, computed axial tomography and immunological tests (McManus et al., 2003).
2. 17. Control and Eradication programs
Some countries, such as Iceland and Cyprus, have already eradicated or are close to eradicating the disease. Control measures in New Zealand and
Australia have significantly reduced the prevalence of E. granulosus.
Successful control programmers are currently being conducted in Turkana
(Kenya), Chile and China, (Schantz, 1990; McManus and Smyth, 1986).
Although control programmers resulting in a marked decrease in the incidence of the disease have been carried out in some countries, little effect has been achieved worldwide. There is some evidence that the disease is spreading because of a lack of meat control, dog management and appropriate legislation (Gemmell 1979; Schwabe, 1986).
2. 18. Control Options and Prevention
Several options for the control of E. granulosus have been thoroughly evaluated and are described in detail (Economides and Christofi, 2002). One option (type I) emphasizes long-term measures of public health education with primary health care (Parodi et al., 2001) and veterinary public health activities, such as the improvement of slaughter hygiene and meat inspection, dog registration and sanitation measures(Gemmell et al,. 2001). Experience from several countries has shown that this option alone may not be sufficient and may be too slow for effective E. granulosus control (Gemmell et al.,
2001). Another option (type II) is based on legislation and includes specific measures targeted to interruption of parasite transmission. Prior to the “attack phase” of the program, base-line data are collected to serve as references for measuring control progress. Important base-line data are the prevalence of E. granulosus in dog populations, the age- dependent prevalence of cysts in animals and human cases of CE. Modern techniques can be used for surveys; for example, the coproantigen ELISA can be used to detect E. granulosus in dog populations (instead of arecoline testing) and ultrasonography alone or in combination with serology can be used for mass diagnosis of CE in humans
(Christofi et al., 2002; Craig, 1997). Specific control measures include stray- dog control, registration of all owned dogs, spaying of bitches and treatment
of all (or most) dogs with praziquantel at predetermined intervals, for example every 6 or 8 weeks. These measures are complemented by upgrading of meat inspection, slaughter hygiene, slaughter offal disposal, public health education and other measures. Control programs in various countries have shown that the attack phase can be successfully concluded in less than 15 years if the necessary measures can be performed without major constraints and financial restrictions (Gemmell et al., 2001).
2. 19. Precautions
Essential precautions are summarized as follows. (1)Personnel involved in handling animals infected with mature intestinal stages of
Echinococcus spp. or egg-contaminated materials should wear protective clothing (cap, face mask, safety glasses, single-use overall, plastic apron, rubber gloves and boots). (2) For work with infected definitive hosts (for example, treatment of dogs), their intestines, fecal matter, or other materials possibly containing infective Echinococcus eggs, special rooms or sterile bench systems should be used. (3) Whole carcasses of carnivores, intestines, or fecal sample possibly containing infective Echinococcus eggs can be decontaminated by deep-freezing at −70 to −80°C. Care should be taken that the effective temperature reaches all parts of the material and is maintained for at least 48 hour. The temperatures of household deep-freezers are too high
to inactivate eggs. Echinococcus eggs are killed within 5 min at +60 to 80°C and instantly at + 100°C. (4) Persons who had a single exposure to infected final hosts or egg-contaminated materials or who had ingested apparently contaminated food should receive serological screening for specific antibodies at the following intervals after the suspected contact: 4 weeks and
6, 12and24 months. Individuals with repeated infection risk (for example, laboratory personnel and field workers in echinococcosis control) should be serologically examined twice a year.
In areas which are free of E. granulosus or have only sporadic occurrence of the parasite, special measures should be taken in order to prevent the introduction of the parasite by living definitive or intermediate host animals
(Eckert and Deplazes, 2004).
CHAPTER THREE
GENERAL MATERIALS AND METHODS
3. 1. Experimental Infection
Infection of Puppies with Echinococcus granulosus
Using Fresh Hydatid Cysts
This part of the study describes experiments to establish infection with
Echinococcus granulosus in the definitive host using hydatid cysts removed from the lungs and livers of naturally infected camels or cattle.
3. 1. 1. Experimental animals
Thirty, puppies of mixed breeds, (approximately 2–6 months old), were used in the experiments. Six experiments were performed, with five, puppies being used in each experiment. Different groups were kept in separate cages in a laboratory in the Department of Parasitology, Faculty of
Veterinary Medicine; University of Khartoum. The cages were cleaned with water and soap, then burned and sprayed with insecticides before introducing the puppies.
Faecal samples from individual puppy were examined separately once a week for three successive weeks to confirm freedom from eggs of Taeniid worms. They were fed on milk and on cooked fish offals obtained from Al
Mawrada, Umdurman restaurants. Sterile dry dog’s meals, composed of dry rise and dry meat, were also available. Clean water was made available all the time. The water and the food containers were cleaned daily. Faecal samples of each puppy were examined, once a week for three successive weeks to confirm freedom from eggs of taeniidea worms. All puppies were kept under similar feeding and management conditions throughout the course of study
(Plate. 1).
3.1.2. Experimental Design
Experimental infection was given orally to 6 different groups of puppies, five in each. The infective doses were 600 viable free protoscolices recovered from the lungs and livers of camels or cattle. Other puppies were infected with intact cysts (Table 2).
Table 2. The Experimental Design Showing the Number of puppies experimentally infected with Hydatid cysts from different origins and organs of naturally infected animals.
Group No. Origin of protoscolices Procedure of Infection
1 Lungs of Camels Iso.Prot.S.M.
2 Livers of camels Iso.Prot.S.M.
3 Lungs of Cattle Iso.Prot.S.M.
4 Livers of Cattle Iso.Prot.S.M.
5 Lungs of Cattle 1.V. H.C. with org tiss
6 Livers of Cattle 1.V. H.C. with org tiss
Iso.Prot.S.M. = Isolated protoscolices with sterile meat 1.V. H.C. with org tiss. = one viable hydatid cyst with organs tissues
3. 1. 3. The Infected Procedures
3.1.3.1. The parasite
Protoscoleces for the infection were obtained from fertile hydatid cysts recovered from the lungs and livers of naturally infected camels and cattle slaughtered in the abattoirs of Khartoum state. The cysts were ensured fertile by demonstrating protoscolices on microscopic examination of cyst fluid.
The viability of these protoscoleces was confirmed following the demonstration of flame cell movements as stated by Smyth & Barrett, (1980) and Calero et al., (1978).
Infection was performed within 4-6 hours after the cysts were collected in the slaughterhouses.
Plate 1. One group of the experimental animals
Plate 2: Photomicrograph showing viable invaginated protoscolices
of Camel origin. x 40.
3.1.3.2. Examination for Eggs
Faecal samples from each dog were examined for eggs of Echinococcus granulosus twice weekly till the first appearance of eggs in the faeces to determine the pre- patent period.
3.1.3.3. Parasite Recovery
The infected puppies were euthanized periodically after the pre- patent period by intravenous injection of 100 mg of Thiopental sodium per puppy.
The Intestines of each puppy were bound before the removal from the carcass in order to prevent the spilling of worms. The small intestines of each puppy were divided into three parts. Each part was placed in a separate container and then slit longitudinally with scissors. Warm physiological saline (0.85%
NaCl) was poured in the three containers to help easy detachment of
Echinococcus worms from the intestinal mucosa. The mucosal surface was then scraped with spatula to free the attached worms.
The contents of each part of the intestines were diluted with physiological saline and small amounts were placed in Petri dishes. The worms were collected with the help of magnifying hand lenses; then they were counted and collected by Pasteur pipette. The procedure was repeated many times for the whole contents of each part. The worms collected were washed several
times to remove the mucous and debris and were left to relax in distilled water in the refrigerator. They were fixed in 10% formalin for at least
24 hours. These worms were examined microscopically, identify confirmed and then evaluated for sexual maturity, and photographed.
3. 1. 4. Precautions
Necessary safety Precautions were taken during handling of infected puppies, their faeces, intestines or other materials possibly containing infective E. granulosus eggs. Laboratory coats, gloves are used to prevent skin from contacting infectious materials (Eckert and Deplazes, 2004; Eckert et al., 2001.
3.2. The Effect of Temperature on The Viability, Survival Time and Infectivity of Hydatid Cysts
To establish effective control programs, it is of epidemiologic importance to obtain an estimation of how long the protoscolices remain viable in discarded carcasses or organs and infective to carnivore hosts. Thus the aim of this part of study was to examine the viability, survival time and the infectivity of Echinococcus granulosus protoscolices at different temperatures by in-vitro and in-vivo evaluation.
3. 2. 1. Testing the Viability and the Survival Time of the Protoscolices of Echinococcus granulosus (In-Vitro)
In this part of the study, the viability and the survival time of E. granulosus protoscolices stored in the refrigerator were examined in vitro.
The viability of the protoscolices within the cysts was determined as such:
0.1 ml. aspirated cyst fluid was put on a microscopic slide and examined under (x 40) magnification. The viability of protoscoleces was determined by flame cell movements in protoscoleces or by the evagination process of the protoscolices as described by (Smyth and Barrett, 1980; and Calero et al.,
(1978).
The survival period of protoscoleces was examined under the conditions represented in table 3.
Table 3. (Table Form for Data collection) Testing the Viability and the Survival time of the Protoscolices of Echinococcus granulosus In-Vitro Days Proto. in the Proto.in N.S. at Proto.in hydatid Cysts in the Number fridge in N.S. room tem fluid in the ridge fridge
V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% First V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D=………...% V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% Second V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D=………...% V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% Third V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D=………...% V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% Forth V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D=………...% V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% Fifth V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D=………...% V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% Sixth V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D= V. en=. ……% V. en=. ……% V. en=. ……% V. en=. ……% Seventh V. evag =.....% V. evag =.....% V. evag =.....% V. evag =.....% D=………...% D=………...% D=………...% D=………...%
..
Proto. = Protoscolices V. = Viable. en. = envaginated. ev. = evaginated. N.S =
Normal saline. D= Death tem. = temperature
Three batches, each containing 100 protoscolices from each group conditions were examined. The average values for viability, evagination and the death of the protoscolices were determined for each group.
According to the results of this experiment; in-vivo, transmission of a stored protoscolices was carried out. Hence experimental infections were performed on 6 groups of puppies in order to examine the infectivity of viable protoscolices from intact hydatid cysts stored inside the refrigerator.
3. 2. 2. Experimental Transmission Using Protoscolices of Echinococcus granulosus stored in the Refrigerator
Protoscoleces used in this infection were obtained from fertile hydatid cysts recovered from the lungs of naturally infected camels. These cysts were preserved in the refrigerator for 1 - 10 days. Twelve puppies were divided into 6 equal groups. Each puppy was infected with 2000 protoscoleces, obtained from hydatid cyst, preserved for 1, 2 4, 6, 8 or 10 days in the fridge.
3. 3. Studies on Hydatid Cyst biology
The study was carried out in Khartoum State during the period,
December 2006 to January 2009. Samples of hydatid cysts were collected from animals slaughtered in different abattoirs of Khartoum State (Plate
3&4). These cysts were obtained from the lungs and livers of naturally infected camels, cattle and from the livers of naturally infected sheep. No cysts were found in goats.
The cysts collected. (149 cysts of camels, 26 cattle and 12 cysts of sheep were collected) were taken in icebox to the Research Laboratory of the
Department of Parasitology and identified as hydatid cysts.
Plate 3. Photograph showing 12 Hydatid cysts from a lung of a camel
slaughtered at Albugaa Abattoir
Plate 4. Hydatid cysts from infected liver and lungs of a camel slaughtered at
El Salam Abattoir, Omdurman, Khartoum State, Sudan
3. 3.1. The Diameter of the Cysts
The cyst’s diameter was determined using an ordinary ruler.
3.3. 2. The Volume of the Cyst’s Fluid
The whole cyst fluid was aspirated using 10-ml. syringes and the
volume determine in measuring of the flasks
3.3. 3. The Status of the cysts
The biological status of cysts was evaluated visually and
microscopically as follows:
i. Fertile cysts: containing fluid with either viable or non viable
protoscolices.
ii. Sterile cysts: containing fluid, but not protosclices iii. Caseated cysts: containing (cheese-like). iv. Calcified: (a) Semi- calcified cysts with a hard wall surrounding cheese- like material. (b) Fully calcified cysts which are stone - like
3. 3. 4. The Form of the Cyst’s Fluid
The aspirated cyst fluid was described as follows:
i. clear (watery)
ii. thick (turbid)
iii. caseated (cheese-like)
3.3. 5. Viability of the Cysts
The viability of the hydatid cysts was evaluated by the presence of viable protoscolices in the cyst fluid or protoscolices on the membranous walls of the germinal layer of the cysts. A drop of the fluid or part of the membranous layer was put on a slide and examined under the microscope at
(x 40) magnification. The viability of the protoscoleces was determined microscopically by the flame’s cell like movements or by the evagination of the protoscoleces.
A drop of fresh, fertile hydatid fluid was placed on a slide with a drop of warm physiological saline (0.9% Na Cl).
The motility of the protosclices was active until the evagination process was completed giving a small worm -like parasites having scolexes, suckers, rostella hooks and calcareous corpuscles (Plate 5).
3. 3. 6. The number of the protoscoleces per cyst
The exact number of the protosclices per cyst was very difficult to determine due to the huge numbers of the protosclices normally present in the hydatid. The whole fluid of the fertile cyst was withdrawn by a sterile 10-ml. syringe then poured into a measuring flask and the cysts were cut open; the walls were scraped and washed, the total volume was determined.
Calculations were performed by counting the numbers of protoscolices in
.01 ml. then, employing the total volume; the number of the protosclices per cyst were calculated.
Plate 5. Photo microscopic showing evagination protoscolices. x10
3.4. Records of Hydatid Cysts in the intermediate host
3.4.1. Record of Hydatid Cysts from Slaughtered Animals in
Khartoum State (1995 – 2008)
Records data for hydatid cysts were obtained from Khartoum State
Corporation for the period 1995 – 2008 representing data from 17 different slaughterhouses in the State. . The total numbers of animals inspected and recorded during that period, were 2179056 for cattle, 3080267 for sheep and
1892 for goats.
Data for hydatid cysts of 218 slaughtered camels were obtained from
Albugaa abattoir during the period from January 2009 to April 2009
3.4.2. Recorded Cases of human hydatidosis in Khartoum State,
(2000- 2009)
3. 4.2.1. Information Sources:
The information presented in this study was collected from the
Department of Histopathology of Khartoum National Health Laboratory and from the Histopathology Laboratory of Soba Hospital.
The samples from patients were collected after surgical operations. These samples were transformed from the surgical department of different hospitals to the National Health Laboratory for histopathological diagnosis.
CHAPTER FOUR l RESULT
4. 1. Experimental Infection
Infection of puppies with Echinococcus granulosus using fresh hydatid cysts collected from the lungs and liver of camels and cattle.
4. 1.1. Transmission of hydatid disease from camels to dogs
4. 1.1.1. Infection of puppies by protoscolices from naturally infected Lungs (Group 1)
Five puppies were infected each with 6000 isolated protoscoleces
from viable hydatid cysts, removed from fresh lungs of naturally infected
camels. They were found positive for Echinococcus granulosus worms at
post mortem (39 – 180) days post infection (Table 4 and Plate 6 and 7).
4. 1.1.1. 1. The pre- patent period
The pre- patent period (p.p.) was found to be between 31 - 55 days
post infection, which was determined by the first appearance of eggs in the
faeces of infected puppies. The mean (x- ) pre- patent period was 40.60
days post infection (Table 4).
4. 1.1.1.2. The infectivity of the worms
The total numbers of worms that were recovered from the intestines of
each infected puppy were range from 1090 to 5400 with a mean (x-) of
3070 worms per puppy. The infectivity of the worms ranged from 18.16
% to 90.07 % respectively, with a mean of 51.18 % (Table 4 & Figure 1).
The Infectivity was calculated as follows:
Total numbers of worms recovered X 100 Total numbers of the protosclices Administered
Table 4: The Infectivity and the pre- patent period of Echinococcus granulosus in experimentally infected puppies with 6000 fresh protosclices from the lungs of naturally infected camels.
Puppies No. of worms Infectivity p.p (dpi) P.M. (dpi) Infected recovered (%) (ova (adult detection) worms detection) 12014 33.56 55 84
21090 18.16 31 96
32849 47.48 45 50
43997 66.62 40 180
55400 90.07 32 39
- - x = 3070 x = 51.18 x- = 40.60 S.D.= 1686.16 S.D.= 28.13
p.p = the pre-patent period P.M. = Post mortem dpi = days post infection
Figure 1. The Infectivity of E. granulosus in experimentally infected puppies with protosclices from the lungs of naturally infected camels
100
90 90.07
80
70 66.62
60
50 47.48
40 Infectivity (%)
33.56 30
20 18.16
10
0 12345 Puppies group
4. 1.1.1.3. Distributions of the worms
The adult Echinococcus granulosus worms were distributed along the small intestines of the infected puppies but they were abundant in the first third of the intestines in most of the infected puppies. The average percentage of the worm distribution in the first parts of the small intestines was 60.78 %
In the second third there were less numbers of worms, with mean percentage of 44.57 %. Few worms were found scattering in the last third of the small intestines of the infected puppies (2.86 %) (Table 5 & Figure 2).
Table 5: Worm burdens and intestinal distribution (%) of Echinococcus granulosus in experimentally infected puppies with 6000 protosclices from the lungs of naturally infected camels.
No. of Total Number of worms in each third of the small Puppies worms intestines (%) recovered First part Second part Third part
1 2014 1773(88%) 185(9%) 56 (3.0 %)
2 1090 295(27.0%) 764(70%) 31(3.0 %)
3 3829 2010(52.5%) 1720(44.9%) 99(2.6%)
4 3997 2110(52.8%) 1815(45.4%) 72 (1.8%)
5 5400 4516(83.6 %) 787(14.6%) 97 (1.8%) average 3070 60.78 % 44.57 % 2.86 %
Figure 2. Percentage of intestinal distribution of E . granulosus in experimentally infected puppies. First Part Secod Part 100 Third Part
90 88 84 80
70 70
60 53 50 52 44 45 40
30 27 20 Percentage Distribution of Worms 15 10 9 332.5 0 22 12345 Puppies Group
Plate 6. Microscopic Photograph showing scolex of E. granulosus x 10
Plate 7. Microscopic Photograph showing adult E. granulosus worm obtained from experimentally infected puppies after 45 days post infection x4
Plate 8. Microscopic Photograph showing a gravid segment of E., granulosus
worm obtained from experimentally infected puppy. X10
4. 1.1.2. Transmission from naturally infected livers of Camels (Group 2)
Five puppies were infected each with 6000 isolated protoscoleces
from viable hydatid cysts, removed from fresh livers of naturally infected
camels. At necropsy four puppies were found positive for Echinococcus
granulosus worms 50 - 66 days post infection (dpi), while one puppy did
not acquire the infection (Table 6).
4. 1.1.2. 1. The pre- patent period
The pre- patent period was found between 45 -59 days post infection.
The average pre- patent period was 39 days post infection (Table 6).
4. 1.1.2. 2. The infectivity of the worms
The total numbers of worms that were recovered from the intestines of
each infected puppy were 0 to 3024 with an average of 1641 worms per
puppy. The infectivity of the worms ranged from (00.00 %) to (50.40%)
respectively, with an average of 27.35% (Table 6 & Figure 3).
Table 6. The Infectivity and the pre- patent period of Echinococcus granulosus in experimentally infected puppies with 6000 fresh protosclices obtained from the livers of naturally infected camels.
Puppies No. of P.P. P.M. Infected worms Infectivity (Days) (Days) recovered (%)
1 0 0 No ova 64
2 3024 50.40 45 50
3 2546 42.43 49 55
4 1500 25.0 52 66
5 1136 18.93 59 55
Table 7. Descriptive Statistics: The Infectivity and the pre- patent period of E. granulosus in infected puppies with 6000 protosclices obtained from the livers of naturally infected camels.
Minimum Maximum Mean Std. Deviation worms .00 3024.00 641.2000 1193.68000 Infectivity .00 50.40 27.3520 19.89000 Prepatent .00 59.00 41.0000 23.48000
Figure 3 Infectivity of hydatid cysts from the lungs & livers of camels in infected puppies 100
90 90.07
80
70 66.62
60
50 50.4 47.48 42.43 40
33.56 30 Infectivity (%) Infectivity 25 20 18.16 18.93
10
0 0 12345Lungs Infectivity (%) Puppies Groups Liver infectivity(%)
Plate 10. Different diameters of Echinococcus granulosus obtained from an
experimentally infected dog with protosclices of naturally infected
camel’s lung. . x4
4. 1. 2. Transmission from cattle to dogs
4. 1. 2. 1. Infection of puppies with isolated protoscolices from natural infected lungs (group 3) Out of five puppies infected each with 6000 viable protoscoleces of
hydatid cysts removed from the lung of naturally infected cattle, none was
positive for E. granulosus worms. The infection was not established in any
puppy.
4.1. 2. 2. Infection of puppies with isolated protoscolices from
Natural infected liver (Group 4)
Similarly, out of five puppies infected each with 6000 viable
protoscoleces from hydatid cysts removed from the liver of naturally
infected cattle, none was found positive for E. granulosus worms. The
infection was not established in the puppies.
4.1. 2. 3. Infection of puppies with intact hydatid cyst from natural infected lungs (Group 5) Here, unlike group 3 and 4, five puppies were infected each with one
intact viable hydatid cyst removed from the lung of naturally infected
cattle. At necropsy they were found positive for Echinococcus granulosus
worms 30 - 60 days post infection (Table 8).
4. 1. 2. 4. . Infection of puppies with intact hydatid cyst from natural infected livers (Group 6) Every puppy which was infected with one intact viable cyst removed from the liver of naturally infected cattle was positive for E. granulosus. The infection was established in all puppies (Table 8).
Table 8. Puppies experimentally infected with protoscolices and intact Hydatid cysts of E. granulosus from naturally infected cattle.
Organ Puppies from No. of P.M. (dpi) (adult P.P (dpi) (ova infected which protosclices Procedure worms detection) (5 each) cysts Administered detection) collected Group 3 Lungs 6000 Iso.Proto.S.M No ova . detected No worms seen (30– 50) d (35 – 60) d.
Group 4 Liver 6000 Iso.Proto.S.M No ova No worms seen . detected (35- 60) d. (30– 50) d.
Group 5 Lungs 1 intact 1.F. H.C. (30 - 60) d. V.H.C. with org. tiss (30– 41) d. Worms detected
Group 6 Liver 1 intact 1.F. H.C. Worms V.H.C. with org .tiss (31– 42) d. detected (30 – 60) d. P. P = the pre-patent period. dpi = days post infection. P. M. = Post mortem. d. = days. 1intact V.H.C. = one intact viable hydatid cyst Iso.Proto.S.M. = Isolated protoscoleces with sterile meat 1. F.H.C. with org. tiss =1 fertile hydatid cyst with organs tissues
4. 2. The Effect of Temperature on the Viability, Survival Time and Infectivity of Hydatid Cysts.
4. 2.1. Testing the viability and the survival time of the Protoscolices of Echinococcus granulosus in-vitro
Observations on the viability envagination, evagination and the survival time of the protoscolices of Echinococcus granulosus in-vitro were shown in
Table 9 and 10 & figure 4.
After 24 hours, the protoscolices in normal saline in the fridge were all viable and envaginated. Fifty percent (50%) of the protoscolices were still viable and envaginated after four days. Complete deaths occurred after seven days from the start of the experiment.
At room temperature 80% and 40% of the isolated protoscolices in normal saline were viable and envaginated after preservation for one and four days respectively. In such condition complete death occurred after six days from the start of the experiment.
The isolated protoscolices placed in hydatid fluid in the fridge remained viable and envaginated for one day at the rate of 93% and for four days at the rate of 63%). Complete death occurred after eight days.
Protoscolices inside hydatid cysts, stored in the fridge, were found all viable and envaginated after three days. Complete deaths occurred after seventeen days of preservation.
Figure 4. Viability of Protoscolices after preservation in various solutions and conditions 120 Proto.in N.S. at 100 room temp.
80 Proto. fridge in N.S.(%) 60 Proto.in hydatid 40 fluid in the fridge (%) 20 Cysts in the fridg (%) Protoscolices Viability(%) 0 135791113Time (days)
*Viability = Viable and envaginated Protoscolices.
Table 9. Viability of Protoscolices after preservation in various solutions and conditions
Days Proto. in the Proto.in N.S. Proto.in Cysts in the Number fridge in at room hydatid fluid fridge N.S.(%) tem.(%) in the fridge (%) (%) V. en. 100 V. en. 80 V. en.93 V. en. 100 First V. ev.20 V. ev.7 V. en. 77 V. en. 67 V. en. 87 V. en. 100 Second V. ev.23 V. ev.33 V. ev.13 V. en.60 V. ev.53 V. en. 73 .V. en 100 Third V. ev.33 D. 47 V. evag.27 D. 7 V. en.50 V. evag.40 V. en. 63 V. en. 93 V. ev.7 Forth V. ev.37 D. 60 V. evag.37 D. 13 V. en.13 V. evag.10 V. en. 40 V. en. 87 V. evag.10 Fifth V. ev.57 D. 90 V. ev.43 D. 3 D. 30 D. 7 V. evag.33 D. 100 V. en. 20 V. en. 80 Sixth D. 67 V. ev.13 V.ev.47 D. 7 D.33 D. 100 D. 100 V.ev.20 V. en. 67 V. ev.20 Seventh D. 80 D. 13
V. =Viable. en. = envaginated. ev. = evaginated. N.S = Normal saline. D= Death tem. = temperature Proto. = protoscolices
Table 10. Viability percentage of the Protoscolices after preservation in
hydatid Cysts in the fridge
Day Percentage of percentage of Death Viable envaginated Viable percentage protoscolices evaginated of protoscolices protoscolices First 100 0 0 Second 100 0 0 Third 100 0 0 Forth 93 7 0 Fifth 87 10 3 Sixth 80 13 7 Seventh 67 20 13 Eighth 67 17 17 Ninth 67 17 17 Tenth 63 20 17 Eleventh 60 17 23 Twelfth 57 20 23 Thirteenth 50 23 27 Fourteenth 33 10 57 Fifteenth 30 7 63 Sixteenth 0 17 83 Seventeenth 0 0 100
Figure 4. Viability of Protoscolices after preservation in various solutions and conditions 120 Proto.in N.S. at 100 room temp. ty (% ) ili 80 Proto. fridge in ab N.S.(%) Vi 60
ces Proto.in hydatid li 40 fluid in the fridge (%) Cysts in the otosco 20 fridg (%) Pr 0 135791113Time (days)
Proto. = Protoscolices N.S. = Normal saline. temp. = Temperature
Figure 5. Viability percentage of the Protoscolices
after preservation in hydatid Cysts in the fridge Percentage of 120 Viable envaginated protoscolices
100
percentage of Viable 80 evaginated protoscolices
60 Death percentage of protoscolices 40 Viability of Protoscolices of Viability 20
0 1234567891011121314151617Time (days)
Figure 6 Viability* (%) of the Protoscolices after preservation in hydatid Cysts in the fridge 120
100 ility (%) 80
60
40
20
Protoscolices Viab Protoscolices 0 1234567891011121314151617 Time (Days)
*Viability = Viable and envaginated Protoscolices
4.2.2. Experimental Transmission Using Protoscolices of Echinococcus granulosus Stored in the Fridge at 4-10 Cº (In- Vivo Studies)
Six groups of puppies were used for this in-vivo experiment. A group consisted of two puppies each infected with 2000 protoscoleces obtained from the lungs of naturally infected camels previously stored in the fridge for 1,, 2,
4, 6 , 8 or 10 days.
Infections established successfully in all puppies. The pre- patent period ranged between 37 – 58 days. Autopsy were done at different times ranging between 40 -75 days after infection (Table 11).
Worms were recovered from all infected puppies and counted. Worm burdens ranged from 176 to 1458 worms. The mean worm count for each group was recorded in Table (12). The infectivity of E .granulosus decreased by the storage time. It was 73% in group 1which infected with protoscolices obtained from cyst previous storage for 1 day, while it decreased to 8.8 %. in the last group (cyst previous storage for 10 day) (Table 11).
Table 11. The infectivity and pre-patent period of E .granulosus in experimentally infected puppies
Group Cyst Average Average Pre- patent P.M No. previous No. of Infectivity period (days post Storage worms (%) (Days) infection) (days) recovered
1 1 1458 73 37 40
2 2 908 45 42 73
3 4 399 19.9 47 55
4 6 407 18.8 45 50
5 8 308 15 50 53
6 10 176 8.8 58 75
Figure 7. The Average Infectivity (%) of Storage Hydatid Cysts in Experimentally Infected Puppies
80
70 Average Infectivity % 60
50
40
30
Average Infectivity (%) 20
10
0 12345678910
Time (Storage days)
4.3. Hydatid Cyst Biology
Samples of hydatid cysts were collected from slaughtered animals in different abattoirs of Khartoum State. These cysts were obtained from the lungs and the livers of naturally infected camels, cattle and sheep. No cysts from naturally infected goats were available.
A total number of 149, 26 and 12 hydatid cysts from naturally infected camels, cattle and sheep were collected, respectively.
4. 3 .1. The Diameter and volume of hydatid cysts
The cyst’s diameter of cysts from camels, cattle and sheep as well as volumes of cysts fluid was measured.
4. 3.1. 1. Hydatid cysts of camels
The minimum diameter of the cyst was 1.3 cm. and the maximum
diameter was 9.5 cm with a range of 8.2 and a mean of 4.65 cm. (Table
18. and Fig. 8). The volume of the fluid obtained from hydatid cysts
ranged between 6 milliliters (minimum) and 50 milliliters (maximum)
respectively (Table 18 and Fig. 9&10).
Table 12. Diameter and Fluid Volume of Hydatid Cysts Collected from Naturally Infected Camels, Cattle & Sheep
Animal Diameter (Cm.) Volume (ml.)
Min. Max. Range Mean Min. Max. Range Mean Camel 1.2 9.5 8.3 4.6 6 150 144 37 Cattle 0.5 10 9.5 3.4 0 60 60 7.6
Sheep 0.9 3 2.1 2.1 0 0.2 0.2 0.17
Figure 8. Mean Diameter of Hydatid cysts 5 Mean Diameter 4
3
Cysts 2
1 Mean Diameter of Hydatid Hydatid of Diameter Mean 0 Camels cattle Sheep Animals
Figure 9.Mean Volume of hydatid cysts Examined 40
35
30 Mean Volume
25
20
15 Mean Volume 10
5
0 Camels cattle Sheep Animals
volume
60
50
40
30 Percent
20
10
0 6.00 9.00 10.0 11.0 12.0 14.0 15.0 16.0 17.0 23.0 25.0 30.0 37.0 38.5 40.0 45.0 47.0 60.0 65.0 150. 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 00 volume
Figure 10. Volume and Percentage of camel’s hydatid cysts
4. 3. 1. 2. Hydatid cysts of Cattle
A number of 26 hydatid cysts of cattle were studied. The
minimum diameter was 0.5 cm. and the maximum diameter was 10 cm
with a range of 9.5 and a mean of 3. 1 cm. (Table 18 and Fig.8 & 11).
The fluid volume in hydatid cysts ranged from very small amount to
60 milliliters (Table 18 and Fig.8 &12) (calcified cysts did not contain fluid)
size
25
20
15 Percent 10
5
0 .50 .80 1.00 1.50 3.00 3.50 4.00 10.00 size
Figure 11. Diameter (Size) and percentages of cattle’s hydatid cysts
volume
60
50
40
30 Percent
20
10
0 .00 .20 .30 .60 3.00 10.00 31.13 60.00 volume
Figure 12. Volume and percentages of cattle’s hydatid cysts fluid
4. 3 .1. 3. Hydatid cysts of sheep
Twelve hydatid cysts of naturally infected sheep were studied.
The cyst diameter was ranging from 0.9 to 3. cm. (Table 12 and
Figure 8 &13). The hydatid cysts collected from the infected rarely contained substantial amount of liquid materials (Table 12 and Figure 8 &14).
size
25
20
15 Percent 10
5
0 .90 1.50 2.00 2.13 2.30 3.00 size
Figure13. Diameter (Size) percentage of sheep’s hydatid cysts
100
80
60 Percent 40
20
0 .00 .20 volume
Figure 14. Volume and percentage of sheep’s hydatid cysts
4. 3. 2. Status of the cysts and cyst fluids
The biological status of the cysts was evaluated visually and
microscopically as:
Fertile cysts are the cysts which contain fluids with viable or non viable protoscoleces. Sterile cysts contain fluids, but without protosclices.
Caseated cysts contain caseous materials; semi- calcified cysts have hard walls surrounding cheese-like material and fully calcified cysts are stone like.
The aspirated cyst fluid was designated as, clear (watery), thick (turbid) or caseated (cheese-like).
Table 13. Fertility of Hydatid Cysts Examined
Animal Organs No. of Fertile cysts Sterile Cysts No. (%) Cysts No. Examined (%)
Camels Lung 132 128 (97%) 4 (3%)
Liver 17 13(76%) 4 (24%) Cattle Lung 21 5 (24%) 16 (76%)
Liver 5 1(20%) 4 (80%)
Lung 2 0 (0%) 2 (100%) Sheep Liver 10 1 (10%) 9 (90%)
As shown in table 13 and figure 15, the fertility rates of the hydatid cysts were higher in the cysts collected from camels than that from cattle.
Fertility rates were also higher in lungs cysts than in liver cysts for both camels and cattle. Hydatid cysts collected from sheep shown lowest fertility rates in livers cysts, No hydatid cysts from lung were collected.
Figure 15. Fertility of Hydatid Cysts of Camels, Cattle & Sheep 120 Lungs Fertility (%) Liver Fertility (%) 100 96
80 76
60 Fertility (%) 40 24 20 20 10 0 0 camels cattle Sheep Animals Organs
4. 3. 2. 1. Hydatid cysts of camels
4. 3. 2. 1. 1. Status
Out of 149 hydatid cysts of camels examined, 141 (96.6%) were fertile with watery clear or turbid fluids. 96% of the Lung’s cysts were fertile and
4% sterile, while 82% of liver’s cysts were fertile and 18% sterile. (Table
14 and Fig. 16).
Table 14. Status of hydatid cysts collected from naturally Infected camels, cattle and sheep
Cyst Status Camels Cattle Sheep
Fertile 141 ((94%) 6 (23.1%) 1(8.3 %)
8 (5.4 %.) 20 (76.9%) 11(91.7 %) Sterile 149 26 12 Total
Figure 16. Fertility percentage of camels,cattle and sheep hydatid cysts 100 90 80 70 60 50 40 Fertility % 30 20 10 0 camels cattle sheep Animals
4. 3. 2. 1. 2. Cyst fluid
Most of the hydatid cysts of camels were found to be distended with fluid describe as either watery turbid fluids (75.4%) or watery clear fluid
(18.1%) while 5.1 % and 1.4% of the cysts semi calcified and semi caseated cysts, respectively (fig.17).
fluid
80
60
40 Percent
20
0 semi cac semi cal wat.clea wat.turb fluid
Figure 17. Status percentage of hydatid cyst’s fluid of camels’ origin
Semi cac = semi caseated Semi cal = semi caseous wat.clea = watery clear wat.turb = watery turbid
4. 3. 2. 2. Cattle hydatid cysts
4.3.2.2. 1. Status
Out of 26 hydatid cysts from naturally infected cattle only 6 (23.1%) were fertile, the remainder 20 (76.9%) were sterile. The fertility rates of cysts from the lungs and the livers of cattle were 24% and 20% respectively ((Table
14 and fig.18).
status
80
60
40 Percent
20
0 fertile sterile status
Figure 18. Status of cattle’s hydatid cysts
4. 3.2.2. 2. Cyst fluid
As seen in table 21 and figure19, most of the hydatid cyst materials of cattle were semi calcified (53.8%), while 26.9 % of them were watery clear and 19.2% were calcified.
Table 15. Fluid Status of hydatid cysts of naturally infected cattle
fluid
Cumulative Frequency Percent Valid Percent Percent Valid ccalcified 5 19.2 19.2 19.2 semicalc 14 53.8 53.8 73.1 wat,clea 7 26.9 26.9 100.0 Total 26 100.0 100.0
fluid
60
50
40
30 Percent
20
10
0 calcifie semicalc wat,clea fluid
Figure 19. Fluid status of cattle's hydatid cysts
4. 3.2.3. Sheep hydatid cysts
4. 3 .2.3. 1. Status
Out of the 12 hydatid cysts of sheep origin collected, 91.7% were sterile and 8.3% were fertile (Table 14 and Fig.16).
4. 3.2.3. 2. Cyst fluid
The status of the hydatid cysts contents of sheep origin is shown in
Table 22 and figure 20.
Table 16. Status percentage of hydatid cyst’s fluid of sheep origin
fluid
Cumulative Frequency Percen Valid Percent Percen Valid calcified 7 58.3 58.3 58.3 caseated 2 16.7 16.7 75.0 semi cas 2 16.7 16.7 91.7 semicalc 1 8.3 8.3 100.0 Total 12 100.0 100.0
Calcified
Semi caseated
Semi calcified
Caseated
Figure 20. Status of hydatid cyst’s fluid from sheep origin
4. 3. 3. The number of the protoscoleces per cyst
The number of the protosclices per cyst was very difficult to estimate, due to the huge numbers of the protosclices in the hydatid cyst.
Nevertheless the numbers of the protoscoleces per fertile hydatid cyst of camels were varied between 2400 and 2700000 with a mean of 502276.4 protosclices (Table 17).
Table 17. Mean & Std.Deviation of the protoscolices numbers
in camel’s hydatid cysts
N Minimum Maximum Mean Std. Deviation protoscolices 149 2400.00 2700000 502276.4 91119.28164
4. 3 4. Percentage of Hydatid cysts in the lungs and livers of the slaughtered animals
4.3. 4. 1. Camels
More than 88 % of the cysts were found in the lungs; while 11.4
% was in the livers (Table 18 & Figure 22).
Table 18. Number of Hydatid cysts recovered from the
Lungs and livers of slaughtered animals
No. of Cysts (%) Lungs Livers Total Animal Camels 132(88.6%) 17(11.4%) 149(100%)
Cattle 21(80%) 5 (19.2%) 26 (100%)
2(17%) 10 (83%) 12 (100%) Sheep
Organ
100
80
60 Percent 40
20
0 liver lung Organ
Figure 21. Hydatid cyst in lungs and livers of camels
4. 3. 4. 2. Cattle
In cattle 80.8 % of the hydatid cysts were collected from the lungs and
19.2 % were collected from the liver (Table 18).
Organ
100
80
60 Percentage 40
20
0 lung liver
Figure 22. Percentage of hydatid cysts in lungs and livers of cattle
4. 3.4. 3. Sheep
More than 83% of the hydatid cysts were from the livers and 17% were
from the lungs of sheep (Table 18 and fig.23).
Organ
Liver
Lung
Figure 23. Hydatid cyst’s percentage in lungs and livers of sheep
4.4. Records of Hydatid Cysts in the Intermediate Host
4.4.1. Record of Hydatid Cysts from Slaughtered Animals in Khartoum State (1995 – 2008)
4. 4. 1.1. Natural hydatid disease in camels
Records of 218 slaughtered camels that were examined in Albugaa abattoir during the period from January 2009 to April 2009, thirty five
(16.1%) camels were infected with hydatid cysts. Thirty four were infected
(97.1%) in the lung and only one camel (2.9%) was found infected in the liver
(Table 26). On the other hand out of 417 camels slaughtered during the period from 1995- 2008; no infections were reported.
4.4. 1. 2. Natural hydatid disease in cattle A total of 2138734 heads of cattle were slaughtered in the different slaughter houses in Khartoum State. Out of these 821 animals (0.0384%) were infected with hydatid cysts (Table 25). Most of the cases were found in the lungs (75%) followed by the liver (17 %) and 8. % were in the Spleen.
4. 4.1. 3. Natural hydatid disease in sheep A total of 3348672 heads of sheep were slaughtered in the different slaughter houses in Khartoum state. Out of these, 12343 (0. 37 %) were
infected with hydatid cysts in different organs, mainly in the liver 11195
(90.7%) from the total infection (Table 19).
4. 4.1. 4. Natural hydatid disease in goats
Out of 1892 goats slaughtered during the period of the study none was infected with hydatid cysts (Table 19).
Table 19. Occurrence of hydatid cyst in slaughtered animals in Khartoum State during the Period 1995 – 2008 Type of animals Sheep Cattle Camel Goats slaughtered
1892 Numbers 3348672 2138734 417 slaughtered 821 0 0 12343 Numbers (.038%) (0. 37 %) infected (%) 0 Liver infected 11195 136 0 (%) (90.) % (17. %)
208 Lung infected (1.8%) 618 (75%) 0 0 (%)
Table 20: Number and percentage of infection with hydatid cysts in slaughtered camels in Albugaa abattoir during the Period January - April 2009 No. of camels examined No. infected No. of No. of Lungs Livers infection infection (%) (%)
218 35 34 1
% (16.1%) (97.1%) (2.9%)
3.4.2. Recorded Cases of human hydatidosis in Khartoum State,
(2000- 2009)
4. 4. 2.1. Analysis of Recorded Cases
The maximum diameter of the cyst encountered was 12 centimeter and the minimum diameter was 2centimeter (Table 21 & 22 and figure 24). The age of the patients ranged between 6 to 55 years old with a mean of 33 years old .Out of these cases 8 (50%) were between 32 -42 years old (Table 21).
Among these patients, the spleen was the most infected organ, out of 16 recorded cases 4(25%) were in the spleen, 3(18.8) were in the liver, 2 (12.5%) were in both kidney and lung. One case (6.3%) was reported in each of the bone, brain, eye, pancreas and the peritoneum (Table 21 and Figure 25).
Females recorded 11 cases (68.8%), while males recorded 5 cases (31.3%) of total recoded cases (Table 21 & Figure 26).
Table 21: Some recorded cases of Human Hydatidosis in Khartoum State during the period 2000-2009. Case Age Sex Organ Area Hospital Cyst No. years affected measuring In Cm. 1 25 Male pancreas North Specialist 6.5 Darfour Cooperation Hospital 2 48 male Right lung Southern Alshab 5x3 Sudan 334 male Spleen Unknown Imperial 5.5x3and5.5 x3.5 x0.3 4 34 female Spleen Unknown Um Bada 6x5
56 FemaleRight Unknown Soba 7.5x9 kidney University
6 32 Female Spleen West Khartoum 12 Darfur Bahari T. hospital 7 35 Female Liver cysts South Soba 6 cyst largest Sudan University 6x4x0.2
8 37 Female Liver cyst Ethiopia Soba 10 University 9 - Female liver Unknown Khartoum 9x8x6 University 10 60 Female Spleen South Omdurman Largest Sudan T. hospital 15.5x9.5
11 13 Male Bone Unknown Alshab 3x2
12 54 Male Brain Unknown Alshab 2x1.5x0.7
13 55 Female Kidney Unknown Umdurman - T. Hospital 14 16 Female Eye Unknown AL Wallideen - Optic Hospital
15 22 Female Peritonea Unknown Khartoum T. - Hospital 16 42 Female Lung Unknown Khartoum 2x2x1.5 T. Hospital
Table 22. Statistical analyses of Patient ages and cyst measurements
Descriptive Statistics
N Range Minimum Maximum Mean Std. Statistic Statistic Statistic Statistic Statistic Std. Error Statistic AGE 16 49.00 6.00 55.00 33.0000 3.49881 13.99524 MEASURING 16 10.00 2.00 12.00 5.7250 .63623 2.54493 Valid N (listwis 16
Figure 24. Hydatid Cyst Measurements of Human Reported Cases
14 12 10 8 6 4
Cysts DiameterCysts 2 0 1234567891011121314 Human Hydatidosis Cases
Table 23. Number and Percentage of organs infected with
Human Hydatid cysts
ORGAN
Cumulative Frequency Percent Valid Percent Percent Valid bone 1 6.3 6.3 6.3 brain 1 6.3 6.3 12.5 eye 1 6.3 6.3 18.8 kidney 2 12.5 12.5 31.3 Liver 3 18.8 18.8 50.0 Lung 2 12.5 12.5 62.5 pancreas 1 6.3 6.3 68.8 Peritone 1 6.3 6.3 75.0 Spleen 4 25.0 25.0 100.0 Total 16 100.0 100.0
25 25.0%
20
18.75%
15
12.5% 12.5% Percent 10
6.25% 6.25% 6.25% 6.25% 6.25% 5
0 Spleen Liver Lung kidney bone Peritone brain pancreas eye ORGAN
Figure 25. Percentage of organs infected with Human Hydatid cysts in Khartoum State
Table 24. Number and Percentage of males and females Infected with Human Hydatid cysts
SEX
Frequency Percent Male 5 31.3 Female 11 68.8 Total 16 100.0
Figure 26. Percentage of Females and Males Human Hydatidosis
80 70 60 50 40 30 Percentage Percentage 20 10 0 Sex Female Male
4. 4. 2.2. Human Reported Cases (16 Cases)
Case: 1
Date: 12/10/2009
Laboratory: Histopathology department, National Health Laboratory
Hospital: Specialist Cooperation Hospital
Patient age: 25 years
Sex: Male
Area: North Darfour , kutum rural
History of rearing animals: during his childhood he raised camels, goats and had a dog with which he had daily intimate contact.
Specimen: Excisional biopsy
Clinical remarks: Abdominal mass. Pancreatic cystic lesion.
Gross examination: cystic mass measuring 6.5 cm in diameter.
Diagnosis: Hydatid cyst.
Histopathologist: Dr. Nadia El Dawi
Case: 2
Date : 24 /9/ 2009
Hospital: Alshab
Unit: Mr. Mohamed Alamin
Patient age: 48 years
Sex: male
Area: Southern Sudan
Specimen: Right lung, biopsy
Gross examination: Membranous tissue, Whitish in color, with smooth inner and outer surfaces, measuring 5x3 cm.
Microscopy examination: the section showed fragments of laminated membranes. No protoscolices were found.
Diagnosis: Hydatid cyst.
Histopathologist: Dr.Nagoud Mohamed Omer
Case: 3
Date: 26 /6/2009
Hospital: Imperial
Physician: Mr. Mohamed Yusif Alnaam
Patient age: 34 years
Sex: male
Specimen: spleen
Clinical information: Abdominal mass. Splenic cyst
Gross examination: Received two pieces of tissues:
1- Cyst soft, grayish in color measuring 5.5x3 cm.
2- Cyst wall was gray to blackish with multiple nodules measuring 5.5
x3.5 x0.3 cm.
Microscopy examination: the section showed cyst wall composed of fibrous laminar layer and germinal layer. There are many protoscolices within the cyst.
Diagnosis: Spleen hydatid cyst.
Histopathologist: Dr Awadia Salman
Case: 4
Date: 20 /6/2007
Hospital: Um Bada
Patient age: 34 years
Sex: Female
Specimen: Spleen
Clinical information: Splenic mass
Gross examination: Received spleen measuring 11x8x8cm.C/s shows yellow mass measuring 6x5cm.
Microscopy examination: L/S mass composed of necrotic tissue with hyaline lining and protoscolices
Diagnosis: Spleen hydatid cyst.
Histopathologist: Dr Nadia El Dawi
Case: 5
Date: 24 /4/2007
Laboratory: Histopathology department, Soba University Hospital.
Hospital: Soba University Hospital
Physician: Mrs. Aziza
Patient age: 6 years
Sex: Female
Specimen: Right kidney
Clinical remarks: Hydatid cyst in the right kidney.
Gross examination: Received Rt. kidney measuring 11x11x9.5cm.with 6cm. of ureter. C/s shows cyst 7.5x9cm. With thick yellowish gelatinous wall and whitish lining filled with yellowish fluid.
Histopathologist: Dr. Nadia El Dawi
Case: 6
Date: 21/1/ 2007
Hospital: Al Khartoum Bahari T. hospital
Patient age: 32 years
Sex: Female
Area: west of Sudan, Al Geniana
History showed rearing animals, Cattles and dogs.
Specimen: spleen
Clinical remarks: Left Hypochondria pain.
• Splenomegaly
• Splenoectomy.
Gross examination: Received 2 containers:
1. Tow pieces of soft tissue whitish membranous with numerous
sand appearances, 12 cm. lengths.
2. Spleen measuring 14x13cm.
Microscopy examination: Sections showing cyst with fibrous tissue wall and germinal layer from which protoscolices project into the lumen.
Diagnosis: hydatid cyst.
Histopathologist: Dr Alawia Miragani.
Case: 7
Date: 6 /7/2006
Laboratory: Histopathology department, Soba University Hospital.
Hospital: Soba University Hospital
Physician: Mr. Omer Al Faroug
Patient age: 35 years
Sex: Female
Area: South Sudan
Specimen: Liver cysts
Gross examination: Received 6 membranous gelatinous soft tissue pieces, the largest measuring 6x4x0.2cm.
Microscopy examination: Sections show cyst wall consisting of laminated membrane
Diagnosis: hydatid cyst.
Histopathologist: Dr. Badereldin Mirgani Yousif
Case: 8
Date: 22 /3/2006
Laboratory: Histopathology department, Soba University Hospital.
Hospital: Soba University Hospital
Physician: Prof. Shaker
Patient age: 37years
Sex: Female
Area: Ethiopia.
Specimen: Liver cyst
Gross examination: Ruptured cyst about 10 cm. with multiple smaller cysts of variable diameter s.
Microscopy examination: Sections show cyst wall lined by a germinal like membrane. Protoscolices of Echinococcus granulosus were also seen.
Diagnosis: hydatid cyst
Histopathologist: Dr. Mohamed Osman
Case: 9
Date: 19 /5/2004
Laboratory: Histopathology department, National Health Laboratory
Hospital: Khartoum University
Physician: Mr. Mohamed Tome
Sex: Female
Specimen: Cystic mass below the liver
Gross examination: Received Cystic mass measuring 9x8x6 cm.
Microscopy examination: Section shows liver cells with cyst lined by 3
layers from outward inward, lymphocytic layer, fibrous capsule and an inner
germinal larger with numerous protoscolices of Echinococcus granulosus
Diagnosis: Liver hydatid cyst
Histopathologist: Dr. Salwa O. Mekki
Case: 10
Date: 10/3/2004
Laboratory: Histopathology department, National Health Laboratory
Hospital: Omdurman Teaching hospital
Unit: Goba University
Patient age: 60 years
Sex: Female
Area: South Sudan
Clinical remarks: Abdominal mass, 4 years under gone laparotomies. The condition recurred.
Specimen: Multiple abdominal masses
Gross examination:
Multiple pieces of tissue, largest 15.5x9.5 cm. cut section soft, containing
whitish material.
Microscopy examination: Wall of cyst with protoscolices.
Diagnosis: Hydatid cyst.
Histopathologist: Dr. Mohamed Abd Alla
Case: 11
Date: 19/4/ 2003
Hospital: Alshab
Physician: Professor/ Basher Ebrahim Mokhtar
Patient age: 13 years
Sex: male
Gross examination: Two containers:
1. multiple pieces of soft white tissue, the largest measuring 3x2
2. Very small pieces of tissue.
Microscopy examination: Walls of cysts with protoscolices.
Diagnosis: hydatid cyst
Histopathologist: Dr. Mohamed Abd alla
Case: 12
Date: 28/4/ 2002
Laboratory: Histopathology department, National Health Laboratory
Hospital: Alshab
Patient age: 54 years
Sex: Male
Specimen: Brain specimen
Gross examination: Fragmented pieces of soft tissues; some were cystic and the others were papillary. The largest was papillary measured 2x1.5x0.7 cm.
Microscopy examination: Lesion showing hydatid cyst with germinal membrane.
Diagnosis: hydatid cyst
Histopathologist: Dr. Awadia Salman
Case: 13
Date: 4/1/2003
Hospital: Umdurman T. Hospital
Patient age: 55 years.
Sex: Female
Specimen: kidney
Gross examination: Multiple pieces of tissues.
Diagnosis: hydatid cyst
Histopathologist: Dr. Mohamed Abd Alla
Case: 14
Date: 2/5/ 2002
Laboratory: Histopathology department, National Health Laboratory
Hospital: AL Wallideen Optic Hospital
Patient age: 16years
Sex: Female
Specimen: Excision biopsy:
Microscopy examination: Ribbons of hyaline membrane of hydatid cyst.
No protoscolices were seen.
Diagnosis: Hydatid cyst.
Histopathologist: Dr. Mohamed Abd Alla
Case: 15
Date: 3/3/ 2002
Laboratory: Histopathology department, National Health Laboratory
Hospital: Khartoum T. Hospital
Patient age: 22 years
Sex: Female
Clinical remarks: Peritoneal hydatid cyst operation was done before 3 years but recurrent.
Specimen: abdominal masses
Microscopy examination: Hyalinized structure, walls of cysts with protoscolices.
Diagnosis: Hydatid cyst.
Histopathologist: Dr. Nadia El Dawi
Case: 16
Date: 2001
Laboratory: Histopathology department, National Health Laboratory.
Hospital: Khartoum T. Hospital
Unit: Prof. Alrasheed
Patient age: 42 years
Sex: Female
History: Had thoracotomy for hydatid cyst 12 years ago presented with discharging sinus. Thoracotomy revealed thickened pleura + small cystic swelling.
Gross examination: One piece of tissue (2x2x1.5 cm.).
Microscopy examination: Hydatid cyst
Diagnosis: The small cystic swelling was a hydatid cyst.
Histopathologist: Dr. Awadia Salman
CHAPTER FIVE
Discussion and Conclusions
Echinococcus granulosus occurs widely in many areas of the world
(Gemmel, 1979). It is an important zoonotic parasite as it is the causative agent of unilocular hydatidosis in humans and animals.
The experimental part of the study was performed to establish the infection of Echinococcus granulosus from the intermediate hosts which are camels, cattle and sheep to the definitive host which is dogs. Hence the actual role of the different intermediate hosts and their organs in the transmission cycle of E. granulosus to canine final host could be studied.
Transmission of E. granulosus to puppies from naturally infected lungs of camels was carried out directly through isolated viable envaginated protoscolices. The camel protoscoleces were infective to all puppies resulting in the development of Echinococcus granulosus worms recovered at autopsy.
The pre- patent period was 31 – 55 days, with an average of 39 days post infection. The infectivity rates of the protoscolices ranged from 18.16 % -
90.07 %, with an average rate of 51.18 %.
In experimental infection studies of Echinococcus granulosus, by viable protoscoleces obtained from the lungs of naturally infected camels, Derbala
and Al-Massry, (1999) stated that camel protoscolices were infective to all puppies and the pre- patent period was 56 days. The results of the present studies confirmed the previous studies, concerning high infectivity rates of the protoscolices removed from camel’s lungs, but it is different in the mean of the pre-patent periods. Mohamed, (2004), Saad and Magzoub, (1989a),
Slepnev, et al., (1977), were also revealed different pre- patent periods and infectivity rates of the protosclices and recoveries of adult worms from infected dogs. These variations, however, could be due to the variations in the temperature and other environmental conditions differences or due to the management reasons. It may also result from strain differences (Eckert and
Thompson, 1997). The age of the animals may be a factor affecting these variations (Soulsby, 1982; Shambesh, 1997).
It is of great interest to notice that most of the experimental transmissions of Echinococcus granulosus from camels to dogs were performed from the infected lungs, (Derbala and El- Masrry, 1999; Eckert, et al. 1989; Idris, 1985; Mohamed, 2004; Saad and Magzoub, 1988;). However, the transmission of viable protoscolices from the liver of infected camels to dogs is not reported in the literature.
The present study shows that the transmission of isolated viable envaginated protoscolices from the liver of infected camels to puppies
revealed long pre-patent periods ranging between 45 to 59 days. The infectivity rates were lower ranging from zero to 50.40% with an average of
27.35%. In many countries, fertility and viability rates of protoscoleces from different animals have been studied (Khan et al., 2001; Scala et al., 2006;
Ahmed et al., 2006). The fertility and viability rates of protoscoleces from different organs of the same animals were studied by the previous authors in slaughtered sheep and cattle to determine the fertility and viability of hydatid cysts. They reported viability of 74.89% and 78.47% of the protoscolices from the liver and the lungs of sheep respectively. Protoscolices of cattle liver and lungs have viability of 78.47% and 80% respectively (Daryani et al.,
2009). Also Ali et al, (2007) reported that, protoscolices in the hydatid cysts from the lung survived longer than those from the liver. The previous studies revealed different viability rates of the protoscolices from the liver and the lungs of sheep and the same for cattle, so similar differences in the viability rates of protoscolices from lungs and liver were also detected in camels in these studies.
It is thus apparent, from this study and previous reports that camels are commonly infected with hydatidosis and have a major contribution role, as intermediate hosts, in the transmission cycle of Echinococcus granulosus in the Sudan.
The successful experimental transmission of Echinococcus granulosus infections to dogs done in Sudan were from hydatid cysts of camel’s lungs origin. In this study trials were performed for establishing Echinococcus granulosus infection in dogs from hydatid cysts of cattle origin. The classic method of counting known numbers of viable isolated protoscoleces to be fed to the puppies was used, but this was not successful and puppies did not yield any eggs,(after 30- 50 days) or adult worms at autopsy ( 35- 60) days.
Macpherson et al., (1985), could not establish infection from cattle to dogs in his research carried in Kenya
In a modified procedure in the present thesis, the transmission was successful when infection was performed using whole intact fertile hydatid cysts instead of isolated protoscolices. Thus the infection was established in all puppies, giving full mature worms after autopsy.
This is the first Successful transmission of Echinococcus granulosus infections from cattle to dogs.
It seems that the effect of peptic enzymes, from the stomach of puppies, affected negatively the development of protoscolices to maturity.
Comparative results were observed for Raillietina tetragona where the cysticercoids, (metacestode), had to be protected in gelatin capsules before infection. It could be possible that protoscolices of cattle origin are more
sensitive to digestive enzymes than those from camel origin; other physiological factors as HCL concentration may prevent the development of the protoscolices, or it may be due to low infectivity rates of the protoscolices.
Thus this phenomenon needs further studies after all.
The present results raise concern, especially in rural setups, where proper disposal of offal and discarded tissues from slaughtered animals are not observed. Hydatid cysts may thus be available for dogs and so a natural transmission cycle is complete. This does not only affect animals but a human health hazard is created as this parasite is a known zoonotic worm. It was noticeable that the risk of getting infected is high in pastoral communities, with poor hygiene and where dogs are used to herd animals (Andersen, 1997).
The comparison of infectivity of capsulated cysts to encapsulated viable protoscoleces was tried to verify the observation that natural infection in final hosts is due to ingestion of whole capsulated cysts. Literature search revealed limited information on transmission of Echinococcus granulosus from cattle to dogs. They were considered as indicators (Rinaldi et al., 2008). More over, reports of high incidence of sterile or calcified cysts lead to the inclination to say that, cattle could not be efficient intermediate hosts.
The present study, however, confirms the role of cattle and camels in leading transmission cycle of Echinococcus granulosus in the Sudan. Thus
the control measures, like Killing rambling dogs, Preventing illegal slaughtering, making healthy slaughterhouses and fencing them (not to allow stray dogs enter to the field of slaughterhouses), public health learning trough radio, TV etc. and teaching cattle holders.
Unfortunately no fertile cysts of sheep origin were available during the experimental period, because nearly all cysts were found either calcified or caseated.
This result indicates that sheep did not play any important role in the transmission cycle of Echinococcus granulosus in the Sudan, because most of hydatid cyst infections of sheep in the Sudan were not fertile. Mohamed,
(2004), found only 9.24 of the total hydatid cysts collected from sheep at
Darfur were fertile. In Khartoum State no hydatid cyst of sheep origin was found fertile (Osman, 2007). Hence Camels and cattle appear to be the principal intermediate hosts for Echinococcus granulosus.
In- vitro studies were performed by observing the viability of isolated protoscolices placed in hydatid fluid and in normal saline at room temperature and then in the fridge. At room temperature, in normal saline, complete death occurred after 6 days. In hydatid fluid kept in the fridge the protoscolices remained viable and envaginated for six days at the rate of 47%; complete death occurred after eight days from the start. While 70% of those
cysts placed in normal saline in the fridge remained viable for 5 days and complete death occurred after 7 days. Complete death occurred after 17 days, when intact protoscolices inside hydatid cysts were placed in the fridge.
Hydatid cyst fluid was the better preservative solution in keeping the protoscolices viable longer than 6 days in comparison with normal saline.
Previous summary of the results, shows that most of the protoscolices inside hydatid cysts from the lungs of camels remain (83%) viable for 10 days in the fridge. This finding indicates how long the dogs could be infected when fed hydatid cysts even if obtained from the fridge. It also means that the infected offal can remains infective for many days in cold weather during winter in Sudan.
Based on the in-vitro results, experimental transmission using protoscolices of Echinococcus granulosus stored in the fridge at 4-10 cº were carried out (in vivo); to prove the infectivity of the viable protoscolices at low temperature or stored in the fridge. All the experimental puppies gave mature
E. granulosus worms at necropsy, with different infectivity rates.
The Infections of E. granulosus established successfully in all experimentally infected puppies although infectivity rates of the protoscolices decreased by time, but they were still able to transmit the infection. Thus
more attention must be given to the removal of infected organs and dead animals from contacting dogs.
The diameter, volume, status of the cysts and cyst fluids were studied.
The numbers of the protoscolices inside the fertile cysts were also studied, for the first time in the Sudan.
Camel’s Hydatid cysts measured each 9.5 cm. for the maximum and 1.3 for the minimum length of diameter. Hydatid cysts of cattle showed the maximum diameter to be 10 cm. and the minimum to be 0.5cm. The diameter of hydatid cyst from sheep ranged between 0.9 cm. to 3.0 cm. for the maximum and the minimum length of diameter respectively. Although this result to some extent agrees with that was reported by (Mohamed, 1997 and Osman, 2007); but it is of great interest to notice that, the severity of the infection was assessed by the diameter of the cysts of the affected organs
(Mirani, et al., 2002). These authors also observed that, old animals suffered more from the disease than the younger ones. Ansari and Rai, (1991) reported that the cysts become larger and more numerous in older animals.
The fluid inside the cyst of camels measured 150 milliliters for the maximum and 6 milliliters for the minimum volume. The maximum volume of the fluid inside cattle’s cyst was 60 milliliters, while the fluid inside hydatid cysts of sheep was too little to be detected and these cysts were
mostly calcified. Actually the amount of the fluid inside hydatid cysts in comparison with the diameter of the cysts, gives indication of how much these cysts exert pressure on the surrounding organs, (Akkiz et al., 1996),
The biological status of the cysts was evaluated visually and microscopically as being fertile with viable protoscolices and sterile without protosclices. In the current studies, high fertility rates of camel’s cysts were found to be (96.4%) and less for cattle, (23.1%) and lower for sheep (8.3%).
Mohamed, (2004), in Darfur region of the Sudan, reported fertility rates of
(73.84%) in camels’ hydatid cysts, 27.49% in cattle and 9.24% in sheep.
Saad, (1985) recorded fertility rates of 37.3% of hydatid cysts of camels.
Fertility rates of (59.8%) of hydatid cysts of camels were mentioned by Tola
(1987). The fertility rates of camel cysts were 29% and 20% in lung and liver respectively as reported by Haridy et al., (1998), in Egypt. In Iran Tavakoli et al., (2008) reported that Lung infection was 1.8 times more than liver one.
These results, to some extent, are similar to our results, on fertility rates of hydatid cysts of cattle and sheep but they are lower than our results of camel’s hydatid cysts.
It is of great interest to notice that our present studies showed more than
95 % of the infections of camels were in the lungs; while the liver percentage represented only 4.3%. This results were similar to the findings of Mohamed,
(1997) who recorded that 73.5% of camel hydatid cysts in the lungs and
18.17% in the liver. This may be due to the fibrotic tissues of the camel’s livers. More than 80 % of hydatid cysts collected from cattle was in the lungs and only 19.2 % were in the liver. These were agreed with (Osman,
2007) who reported that, 100% of the cattle cysts were in the lungs.
Hydatid cysts of sheep origin were 91.7% sterile and 8.3% fertile.
The material inside hydatid cysts of sheep was 58.3 % calcified, 33.4% caseated or semi caseated and 8.3% semi calcified. This finding agrees with
Saad and Magzoub, (1989b) who reported that calcification is the predominant feature in sheep hydatid cysts. These findings are in contrast with findings in other parts of the world where sheep are heavily involved in the transmission of E. granulosus (Anderson et al., 1977).
The numbers of the protoscoleces in each fertile hydatid cyst obtained from camels were found to range from 2400 to 2700000. The cysts from the lungs of infected camels carried high numbers of protoscolices than the cysts from the liver. The huge numbers of the protoscolices per cyst explained the high infestation rates of the adult Echinococcus granulosus worms found in dogs as final hosts. Studies concerning the numbers of the protoscolices in every cyst were not available in the recorded literature.
Most prevalence studies have relied on slaughterhouses records, such records are considered as economical ways of collecting and analyzing information on livestock disease (Macpherson and Karstad, 1981; Baldock et al., 1985). Also lesions of cystic echinococcosis usually remain throughout the life of animals and so, at post-mortem examination it is possible to tell whether or not an animal is infected (Njoroge, et al., 2000).
Although there might be some faults in data gathering but we can say that slaughterhouses are the sole and best places for estimation of infestation rates, because infections like hydatidosis, Fascioliasis, Tuberculosis, lung lesions.. etc. can be detected by gross examination (Colon, 2002).
However, hydatid disease in the Sudan, has just recently been considered as a recognized zoonoses, but no comprehensive epidemiologic investigation has been done for comparison between livestock and human hydatidosis during a specific period of time
Previous studies on survey prevalence of hydatidosis in Khartoum showed that 8.9% of sheep and 4.2% of goats were infected with hydatid cysts (El sawi, 1994). Hydatid cysts prevalence was 43.9% in camels examined by El Sawi and Saad (1995).
In the present studies on natural infection with hydatid cysts in slaughtered animals, as intermediate hosts, during the period from 1995-
2008; information was collected from the records of slaughter houses in
Khartoum State. The mean prevalence rate of hydatidosis of cattle and sheep were 0.038% and 0.37%, respectively. However a special record of 238 slaughtered camels examined in Albugaa abattoir showed that 35 (16.1%) camels were infected with hydatid cysts. No infections of goats had been recorded. In Omdurman slaughterhouse El sawi (1994) found an infection rate of 8.9% in sheep and 4.2% in goats. It was 43.9% in camels when examined by El Sawi and Saad, (1995). Elmahdi, (2003) reported infection rate of 45% in camels examined in Omdurman, Tampool and Madani. It was 7% in sheep and 3% in cattle.
These findings show some dissimilarity with previous studies. The low grade of camel infection is due to the fact that: camel’s lungs are not consumable organs, so no proper examination is usually given to them during meat inspection.
Slaughterhouses records show no infections of goats. This may be due to the nature and the way of feeding, where goats feed mainly by browsing rather than grazing, so usually exhibit low rates of infection. Management system or the host immunity may play other factors. We also observed that, more than 88% of camel infections were in the lungs and only 11.4% of the infections were in the liver; Haridy et al, (1998) reported similar findings.
While in cattle (75%) of the infections were in the lungs followed by (17 %) in the liver. In sheep the highest percentage of infections were recorded in the liver (90.7%). These results are in agreement with most of the previous studies.
According to the data and information collected for human hydatidosis in this study, only sixteen cases of patients had the opportunity to attend surgical operation in Khartoum State during the period 2000- 2009. The measurement of the cysts showed the maximum diameter as being 12 cm. and
2 cm. as being the minimum diameter.
Similarly Ammann and Eckert, (1996) and Shambesh, (1997) reported that, the diameter of the cyst in human body is highly variable and usually ranged between 1 and 15 cm.
The ages of the patients ranged between 6 and 55 years. Among the recorded cases (50%) were found within the age of 32 -42 years. This result was similar to the recorded cases of Ammann and Eckert, (1996); Pawlowski, et al., (2001) who reported that, in some areas of endemic infection, most hospital cases were recorded in the age groups between 21 and 40 years.
The highest prevalence of infected organs were the spleen, (25% of cases), while 18.8% were in the liver.
Female patients were found to be 68.8% of the cases, while males were found to be 31.3%.
An ultrasonographic survey in Italy revealed that 60% of 424 individuals were asymptomatic (Caremani, et al., 1993). In the Sudan, Mohamed and
Aradaib, (2006) stated that hydatid lung disease is often asymptomatic and usually the surgical interference is not generally recommended unless the cyst interacts with the normal function of the affected organ. Saad, (1985) recorded 6 cases; Eisa et al., (1962) mentioned several operations for removal of hydatid cysts, performed at Kapoeta and Torit hospitals. Cahill et al.,
(1965) reported 13.1% positive cases in a serological study in southern
Sudan. The prevalence rates of human population in Khartoum were 1.2 %
(Tola, 1987). Macpherson et al., (1989b) reported prevalence between 0.5 % and 3.5% in human hydatidosis in Southern Sudan. Njoroge, et al., (2001) carried out a survey of cystic echinococcosis in southern Sudan; the study indicated that the prevalence of cystic echinococcosis in Southern Sudan may be higher than in other parts.
As a conclusion of this study, the following crucial points are considered
The classic method of feeding the experimental puppies viable isolated protoscoleces obtained from cattle was not successful in the transmission of
E. granulosus. This lead to perform a modified procedure by which the
transmission was directly done when it was performed using the whole intact fertile hydatid cysts instead of isolated protoscolices. Thus the infection was established in all puppies, giving full mature worms after autopsy.
Thus the study confirms the important role of camels and cattle in leading transmission cycle of Echinococcus granulosus in the Sudan. Thus the control measures should not only target camels but also cattle.
It appears that Sheep not play an important role in the transmission cycle of Echinococcus granulosus in the Sudan.
The ages of hydatidosis patients involved, ranged between 6 and 55 years.
In – vitro studies revealed that, protoscolices inside hydatid cysts from the lungs of camels remain viable (83%) for 10 days in the fridge. These viable protoscolices were found infective to experimental puppies.
This finding indicates how long the dogs could be infected when fed
hydatid cysts stored in the fridge even for 2 weeks.
Protoscolices inside intact hydatid cysts survived in – vitro for a long time than those isolated in hydatid fluid.
We recommend safe disposal of infected offal, especially of camels and in
particular the lungs which are not consumable organs. Thus this will
definitely reduce the transmission cycle of Echinococcus granulosus in the
Sudan.
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دراﺳﺎت ﺗﺠﺮﻳﺒﻴﺔ ﻟﻤﺮض اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ ﺑﺎﻟﺴﻮدان: ﻋﺪوى ﺗﺠﺮﻳﺒﻴﺔ وإﺻﺎﺑﺔ ﻃﺒﻴﻌﻴﻪ ﻣﺴﺘﺨﻠﺺ اﻟﺪراﺳﺔ:
اﻟﻌﻤﻞ اﻟﻤﻘﺪم ﻓﻲ هﺬﻩ اﻷﻃﺮوﺣﺔ ﺷﻤﻞ أرﺑﻌﻪ ﻣﺤﺎور أﺳﺎﺳﻴﺔ. ﻋﺪوى ﺗﺠﺮﻳﺒﻴﺔ أدت إﻟﻲ إﻋﺎدة اﻟﺪﻳﺪان اﻟﻜﻠﺒﻴﺔ (Echinococcus granulosus) اﻟﺒﺎﻟﻐﺔ إﻟﻰ أﻣﻌﺎء اﻟﺠﺮاء اﻟﺘﻲ ﺗﻌﺮﺿﺖ ﻟﻠﻌﺪوى اﻟﺘﺠﺮﻳﺒﻴﺔ . آﻤﺎ أﻧﺠﺰت ﺑﻌﺾ اﻟﺪراﺳﺎت اﻟﻤﺨﺘﺒﺮة داﺧﻞ اﻟﻤﺤﺎﻟﻴﻞ -In (vitro) ﺷﻤﻠﺖ إﺣﻴﺎﺋﻴﺔ اﻟﺮؤﻳﺴﺎت اﻷوﻟﻴﺔ Protoscolices اﻟﻤﻨﻌﺰﻟﺔ وﺗﻠﻚ اﻟﻤﺘﺤﻮﺻﻠﺔ داﺧﻞ اﻟﻜﻴﺲ واﻟﺘﻲ ﺗﻢ اﻟﺤﺼﻮل ﻋﻠﻴﻬﺎ ﻣﻦ رﺋﺎت اﻟﺠﻤﺎ ل اﻟﻤﺼﺎﺑﺔ . ﻋﻼوة ﻋﻠﻰ ذﻟﻚ ﺳﺠﻼت ﻟﺘﻮاﺟﺪ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ ( اﻟﻌﺪارﻳﺔ ) ﻓﻲ اﻟﻌﺎﺋﻞ اﻟﻮﺳﻴﻂ . اﻟﻌﺪوى اﻟﺘﺠﺮﻳﺒﻴﺔ ﻟﻠﺠﺮاء اﻟﺮؤﻳﺴﺎت اﻷوﻟﻴﺔ اﻟﻤﻌﺰوﻟﺔ ﻣﻦ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ ، واﻟﺘﻲ ﺗﻢ اﻟﺤﺼﻮل ﻋﻠﻴﻬﺎ ﻣﻦ اﻟﺠﻤﺎل اﻟﻤﺬﺑﻮﺣﺔ اﻟﻤﺼﺎﺑﺔ، أﻇﻬﺮت دﻳﺪان ﺑﺎﻟﻐﺔ ﻟﻠﺪودة اﻟﻜﻠﺒﻴﺔ ﻓﻲ اﻷﻣﻌﺎء اﻟﺪﻗﻴﻘﺔ ﻟﺠﺮاء اﻟﺘﺠﺮﺑﺔ. ﺳﺠﻠﺖ اﻟﺮؤﻳﺴﺎت ذات اﻷﺻﻞ اﻟﺮﺋﻮي ﻧﺴﺒﺔ إﻋﺪادﻳﺔ اﻋﻠﻲ ﻣﻦ ذات اﻷﺻﻞ اﻟﻜﺒﺪي ﻟﻠﺠﻤﺎ ل. أﻋﺪاد اﻟﺪﻳﺪان اﻟﻤﺠﻤﻮﻋﺔ آﺎﻧﺖ أآﺜﺮ ﻓﻲ اﻷﺟﺰاء اﻟﻌﻠﻴﺎ ﻷﻣﻌﺎء اﻟﺠﺮاء ﻣﻦ اﻷﺟﺰاء اﻟﺴﻔﻠﻰ ﻟﻸﻣﻌﺎء. اﻟﻌﺪوى اﻟﺘﺠﺮﻳﺒﻴﺔ ﻟﻠﺠﺮاء اﻟﺮؤﻳﺴﺎت اﻷوﻟﻴﺔ اﻟﻤﻌﺰوﻟﺔ ﻣﻦ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﺒﻘﺮﻳﺔ اﻷﺻﻞ ﻟﻢ ﺗﻨﺠﺢ ﺣﻴﺚ ﻟﻢ ﺗﻮﺟﺪ إي أﻃﻮار ﻣﻦ اﻟﺪﻳﺪان ﻓﻲ اﻷﻣﻌﺎء اﻟﺪﻗﻴﻘﺔ ﻟﺠﺮاء اﻟﺘﺠﺮﺑﺔ. ﺗﻢ اﺳﺘﺨﺪام ﻃﺮﻳﻘﺔ ﻣﺴﺘﺤﺪﺛﺔ ﺗﺤﻘﻖ ﺑﻬﺎ اآﺘﻤﺎل اﻟﻌﺪوى ﻋﻨﺪﻣﺎ أﻋﻄﻴﺖ اﻟﺠﺮاء اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﺒﻘﺮﻳﺔ اﻷﺻﻞ آﻤﺎ هﻲ ﺑ ﺪ ﻻً ﻋﻦ اﻟﻌﺪوى اﻟﺮؤﻳﺴﺎت اﻷوﻟﻴﺔ اﻟﻤﻌﺰوﻟﺔ. ﺧﻼل اﻟﻌﻤﻞ اﻟﺘﺠﺮﻳﺒﻲ ﺗﻢ اﻟﺘﺤﻘﻖ ﻣﻦ اﻟﻌﺪوى ﺑﺎآﺘﺸﺎف ﺑﻮﻳﻀﺎت اﻟﺪﻳﺪان اﻟﻜﻠﺒﻴﺔ ﻓﻲ ﺑﺮاز اﻟﺠﺮاء ، ﻣﻦ ﺛﻢ ﺗﺤﺪﻳﺪ اﻟﻔﺘﺮة ﻗﺒﻞ اﻟﺒﺎﺋﻨﺔ ﻣﻦ ﻣﻮﻋﺪ اﻟﻌﺪوى وﺣﺘﻰ ﻣﻮﻋﺪ ﻇﻬﻮر أول ﺑﻮﻳﻀﺔ ﻓﻲ ﺑﺮاز ﺟﺮاء اﻟﺘﺠﺮﺑﺔ، ﺗﻠﻚ اﻟﺘﻲ ﺗﺮاوﺣﺖ ﻣﺎﺑﻴﻦ 31 - 55 ﻳ ﻮ ﻣ ﺎً. أﻧﺠﺰت دراﺳﺎت ﺗﺠﺮﻳﺒﻴﺔ ﻣﻌﻤﻠﻴﺔ داﺧﻞ اﻟﻤﺤﺎﻟﻴﻞ ( In- vitro ) ﻋﻠﻰ ﺣﻴﻮﻳﺔ اﻟﺮؤﻳﺴﺎت اﻷوﻟﻴﺔ اﻟﻤﻌﺰوﻟﺔ ﻣﻦ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﻤﺠﻤﻮﻋﺔ ﻣﻦ اﻟﺠﻤﺎل اﻟﻤﺼﺎﺑﺔ، ﺣﻴﺚ وﺿﻌﺖ ﺗﻠﻚ اﻟﺮؤﻳﺴﺎت ﻓﻲ ﻣﺤﻠﻮل ﻣﻠﺢ اﻟﻄﻌﺎم (8.5 % ) ، ﻣﺤﻠﻮل اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ ، ﺛﻢ اﻟﺮؤﻳﺴﺎت داﺧﻞ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ .
وﺿﻌﺖ ﻣﺠﻤﻮﻋﺔ ﻣﻦ ﺗﻠﻚ اﻟﻤﺤﺘﻮﻳﺎت ﻓﻲ درﺟﺔ ﺣﺮارة اﻟﻐﺮﻓﺔ ﺑﻴﻨﻤﺎ وﺿﻌﺖ ﻣﺠﻤﻮﻋﺔ أﺧﺮي ﻓﻲ اﻟﺜﻼﺟﺔ. 40 % ﻣﻦ اﻟﺮؤﻳﺴﺎت داﺧﻞ ﻣﺤﻠﻮل ﻣﻠﺢ اﻟﻄﻌﺎم ﻓﻲ درﺟﺔ ﺣﺮارة اﻟﻐﺮﻓﺔ ﺑﻘﻴﺖ ﺣﻴﺔ ﻧﺸﻄﺔ ﻟﻤﺪة 4 أﻳﺎم ﺑﻴﻨﻤﺎ ﺟﻤﻴﻌﻬﺎ ﻣﺎﺗﺖ ﺑﻌﺪ 6 أﻳﺎم ، ﺑﻘﻴﺖ 70% ﻣﻦ ﺗﻠﻚ اﻟﺘﻲ وﺿﻌﺖ ﻓﻲ ﻧﻔﺲ اﻟﻤﺤﻠﻮل داﺧﻞ اﻟﺜﻼﺟﺔ ﺣﻴﺔ ﻧﺸﻄﺔ ﻟﻤﺪة 5 أﻳﺎم ﻟﻜﻨﻬﺎ ﻣﺎﺗﺖ ﺟﻤﻴﻌﻬﺎ ﺑﻌﺪ 7 أﻳﺎم. اﻟﺮؤﻳﺴﺎت اﻟﻤﻮﺟﻮدة داﺧﻞ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ واﻟﺘﻲ وﺿﻌﺖ داﺧﻞ اﻟﺜﻼﺟﺔ ﺑﻘﻴﺖ ﺣﻴﺔ ﺑﻨﺴﺐ ﻋﺎﻟﻴﺔ وﻟﻢ ﺗﻤﺖ ﺣﺘﻰ اﻟﻴﻮم اﻟﺴﺎﺑﻊ ﻋﺸﺮ. ﺗﺒﻌﺖ اﻟﺪراﺳﺎت اﻟﺘﺠﺮﻳﺒﻴﺔ اﻟﻤﻌﻤﻠﻴﺔ داﺧﻞ اﻟﻤﺤﺎﻟﻴﻞ دراﺳﺎت داﺧﻞ اﻟﻌﺎﺋﻞ (In- Vivo ) ﻟﻤﻌﺮﻓﺔ ﻣﺪي ﻓﻌﺎﻟﻴﺔ اﻟﺮؤﻳﺴﺎت اﻟﻤﺤﻔﻮﻇﺔ اﻟﻤﻮﺟﻮدة داﺧﻞ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ واﻟﻤﻮﺿﻮﻋﺔ داﺧﻞ اﻟﺜﻼﺟﺔ ﻟﻔﺘﺮات ﻣﺨﺘﻠﻔﺔ ﺑﻌﺪ اﻟﻘﻴﺎم ﺑﺎﻟﻌﺪوى اﻟﺘﺠﺮﻳﺒﻴﺔ ﻟﻠﺠﺮاء ﺑﺘﻠﻚ اﻟﺮؤﻳﺴﺎت و ﻗﺪ ﺗﻤﺖ اﻟﻌﺪوى اﻟﺘﺠﺮﻳﺒﻴﺔ ﺑﻨﺠﺎح ﺟﻤﻌﺖ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﺘﻲ ،اﺳﺘﺨﺪﻣﺖ ﻟﻠﺪراﺳﺔ اﻹﺣﻴﺎﺋﻴﺔ، ﻣﻦ اﻟﺠﻤﺎل ،اﻷﺑﻘﺎر واﻟﻀﺎن اﻟﻤﺬﺑﻮﺣﺔ ﺑﺴﻠﺨﺎﻧﺎت وﻻﻳﺔ اﻟﺨﺮﻃﻮم اﻟﻤﺨﺘﻠﻔﺔ .ﻟﻢ ﻧﺤﺼﻞ ﻋﻠﻰ أآﻴﺎس ﻣﺎﺋﻴﺔ ﻟﻠﻤﺎﻋﺰ. ﺗﻤﺖ دراﺳﺔ ﻗﻄﺮ وﺣﺠﻢ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ وﻋﺪد اﻟﺮؤﻳﺴﺎت داﺧﻞ آﻴﺲ. ﺑﻠﻎ أﻗﺼﻰ ﻗﻄﺮ ﻟﻸآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﻤﺠﻤﻮﻋﺔ ﻣﻦ اﻟﺠﻤﺎل 9.5 ﺳﻢ ﺑﻴﻨﻤﺎ آﺎن أدﻧﻰ ﻗﻄﺮ 1.3 ﺳﻢ أﻣﺎ ﺣﺠﻢ اﻟﺴﺎﺋﻞ ﻓﺘﺮاوح ﺑﻴﻦ -150 6 ﻣﻞ. اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﺒﻘﺮﻳﺔ اﻷﺻﻞ ﺑﻠﻎ أﻗﺼﻰ ﻗﻄﺮ ﻟﻬﺎ 10 ﺳﻢ واﻗﻞ ﻗﻄﺮ 0.5 ﺳﻢ ، أﻣﺎ ﺣﺠﻢ اﻟﺴﺎﺋﻞ ﻓﺘﺮاوح ﺑﻴﻦ اﻟﻤﻌﺪوم ﻓﻲ اﻷآﻴﺎس اﻟﻤﺘﺤﺠﺮة إﻟﻲ 60 ﻣﻞ آﺄﻗﺼﻰ ﺣﺠﻢ . ﺑﻠﻎ أﻗﺼﻰ ﻗﻄﺮ ﻟﻸآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﻤﺠﻤﻮﻋﺔ ﻣﻦ اﻟﻀﺎن 3 ﺳﻢ ﺑﻴﻨﻤﺎ آﺎن أدﻧﻰ ﻗﻄﺮ 0.9 ﺳﻢ، أﻣﺎ ﺣﺠﻢ اﻟﺴﺎﺋﻞ ﻓﻜﺎن ﻏ ﺎ ﻟ ﺒ ﺎً ﻗﻠﻴﻞ ﻻ ﻳﻤﻜﻦ ﺳﺤﺒﻪ. ﺗﻢ ﺗﻘﻴﻴﻢ اﻟﻮﺿﻊ اﻷﺣﻴﺎﺋﻰ ﻟﻸآﻴﺎس ﻣ ﻈ ﻬ ﺮ ﻳ ﺎً وﻣﺠﻬﺮﻳﺎ ﺑﺄآﻴﺎس ﺧﺼﺒﺔ، ﺗﻠﻚ اﻟﺘﻲ ﺗﺤﻤﻞ رﺋﻴﺴﺎت أوﻟﻴﺔ ،وﻋﻘﻴﻤﺔ ﺗﻠﻚ اﻟﺨﺎﻟﻴﺔ ﻣﻦ اﻟﺮؤوس. ﻣﻦ ﺑﻴﻦ 138 آﻴﺴﺎ ﺟﻤﻊ ﻣﻦ اﻹﺑﻞ 96.4% آﺎن ﺧﺼﺐ، وﻣﻦ ﺑﻴﻦ 26 آﻴﺲ ﺟﻤﻊ ﻣﻦ اﻟﺒﻘﺮ 23% آﺎﻧﺖ ﺧﺼﺒﺔ وآﻞ اﻟﺒﻘﻴﺔ آﺎﻧﺖ ﻋﻘﻴﻤﺔ. اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ اﻟﺘﻲ ﺟﻤﻌﺖ ﻣﻦ اﻟﻀﺎن آﺎن 96.7 % ﻣﻨﻬﺎ ﻋﻘﻴﻢ. ﻧﺘﺎﺋﺞ اﻟﺪراﺳﺎت اﻟﺘﻲ ﺗﻢ اﻟﺤﺼﻮل ﻋﻠﻴﻬﺎ ﻣﻦ اﻟﺴﺠﻼت ﺑﻴﻨﺖ ﺗﻮاﺟﺪ اﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ ﺑﻴﻦ اﻟﺠﻤﺎل، اﻷﺑﻘﺎر، اﻟﻀﺎن واﻟﻤﺎﻋﺰ ﻓﻲ وﻻﻳﺔ اﻟﺨﺮﻃﻮم ﺧﻼل اﻟﻔﺘﺮة 1995- 2008م. ﺳﺠﻠﺖ أﻋﻠﻰ ﻧﺴﺒﺔ إﺻﺎﺑﺔ ﻓﻲ اﻹﺑﻞ ﺗﻠﺘﻬﺎ اﻷﺑﻘﺎر وأﻗﻞ ﻧﺴﺒﺔ إﺻﺎﺑﺔ وﺟﺪت ﻓﻲ اﻟﻀﺎن،ﺑﻴﻨﻤﺎ ﻟﻢ ﺗﻈﻬﺮ إﺻﺎﺑﺎت ﻓﻲ اﻟﻤﺎﻋﺰ. أﻇﻬﺮت ﺑﻌﺾ ﻣﺼﺎدر اﻟﻤﻌﻠﻮﻣﺎت اﻟﺘﻲ ﺗﺨﺺ إﺻﺎﺑﺔ اﻹﻧﺴﺎن ﺑﺎﻷآﻴﺎس اﻟﻤﺎﺋﻴﺔ ﻓﻲ اﻹﻧﺴﺎن آﻌﺎﺋﻞ وﺳﻴﻂ ﺑﻮﻻﻳﺔ اﻟﺨﺮﻃﻮم ﻓﻲ اﻟﻔﺘﺮة ﻣﺎ ﺑﺒﻴﻦ 2000 اﻟﻰ2009 .اآﺒﺮ ﻗﻄﺮ ﻟﻸآﻴﺎس اﻟﻤﺎﺋﻴﺔ 12ﺳﻢ ﺑﻴﻨﻤﺎ اﺻﻐﺮ ﻗﻄﺮ2 ﺳﻢ .ﺗﺮاوﺣﺖ أﻋﻤﺎرهﻢ ﻣﻦ 6 ﺳﻨﻮات إﻟﻰ 55 ﺳﻨﺔ.
Appendixes
Plate 1. Life cycle of Echinococcus granulosus
(From: Parasite and Health. Echinococcosis, 2009)
Plate 2. An illustration of Life cycle of Echinococcus
(From: Niklaus Weiss and Joachim Pelikan, Swiss Tropical Institute, 2007, Introduction to Diagnostic Medical Parasitology)
Plate 3. Echinococcus granulosus. Adults (Scale is in mm) (Veterinary Parasitology Vpth603 Laboratory, University of Pennsylvania, 2005)
Plate 4. Schematic illustration of hydatid cyst
(Veterinary Parasitology Vpth603 Laboratory, University of Pennsylvania, 2005)
!Error
Plate 5. Larval types found in the taeniid tapeworms.
(Muller, 1975)
Plate 6. Microscopic photograph showing Echinococcus granulosus scolex
(From:) DIAGNOSING MEDICAL PARASITES. page 133.)
:
Plate 7. Eggs of Echinococcus granulosus
(From: simple-medicine, 2008)
plate 8. Microscopic photograph showing the morphology of
Echinococcus granulosus adult worm
(Simon and Wildsmith,(2008)
Plate 9. Hydatid cysts in a horse liver
(From : British society of veterinary pathology( 2007)
!
Plate 10. Gross pathology of membrane and hydatid daughter cysts from
A human lung. (Abdul Ghaffar and Gregory Brower,(2010) In, Microbiology and
Immunolgy On – Line University of South Carolina, School of Medicine.)
Plate 11. A huge ovarian cyst arising from the right ovary of a woman (Parray, et al., 2007)
Plate 12. Hydatid cysts removed from the liver of a human.
{(University of Pennsylvania.Veterinary Parasitology VPTH603 Laboratory,2005 cal.vet.upenn.edu/.../website/lab6new2009.htm}
Plate 13. Hydatid Cyst – orbit.
Gordon K. Klintworth, MD, Joseph A. C. Wadsworth,(2002) Duke University Medical
Center, Durham, North Carolina USA. DHTS Web Services
!Error
Plate 14. Appearance of a typical cyst at removal
From Wikipedia, the free encyclopedia Ekmirajkar (2007)
. Plate 15. Hydatid cysts infect lungs, liver, and other internal organs of big game animals. {Michigan DNR Wildlife Disease Lab photo (Western Institute for Study of the Environment Commentary)}