1

Taenia hydatigena :

Predilection site: Small intestine

Description : hydatigena is a large tapeworm measuring up to 5 m in length. There are 26-44 hooks on the rostellum, arranged in two rows. The gravid proglottids are about 8-10mm long by 4-7 mm broad. The median uterus has 5-10 lateral branches on each side. The metacestode stage of this species is called Cysticercus tenuicollis, and it is found in the peritoal cavity of sheep, goat, cattle and pig, some wild and some rodents, such as hamster. The semi-transparent cysticercus may be up to 5-7 cm in size and contains a watery fluid and invaginated scolex with a long neck.

Final hosts : The adult tapeworm is found in dogs and wild carnivores.

Intermediate hosts : Sheep, goat, cattle and pig, some wild animals and some rodents, such as hamster Geographical distribution : Worldwide

Life cycle : The biology of this species is similar of basic life cycle in tapeworms of . The oncospheres, infective to sheep, goat, cattle and pig, are carried in the blood to the liver in which they migrate for about 4 weeks before they emerge on the surface of this organ and attach to the peritoneum. Within a further 4 weeks each develops into the characteristically large metacestode, C. tenuicollis. The complete life cycle T. hydatigena is around 7-8 months.

Pathogenesis and clinical signs : Adult tapeworms in dogs are usually asymptomatic. However, in heavy infections there may be gastrointestinal disturbances suc as diarrhoea, abdominal pain and anal pruritis that result from the migration of proglottids from the perianal area. The young metacestode, ( C. tenuicollis - larval stage), may cause serious diseases of livestoks animals, especially sheeps and goats, which are intermediated hosts. They damage and destroy the substance of the liver as they migrate through it, causing haemorrhage. Infrequently, large numbers of developing C. tenuicollis migrate contemporaneously in the liver of the sheep, goat and pig producing “ hepatitis cysticercosa” , a condition whose gross pathology resembles acute and which is often fatal. Severe infection of the liver or tissue may result in liver and carcass condemmation at slaughter. The mature C. tenuicollis in the peritoneal cavity are usually not pathological. Sometimes, infected sheep may be present loss of condition, emaciation and ascites .

Diagnosis : Often the first sign of tapeworm infection in dogs in the presence of proglottids in the faeces or more frequently the perianal area as a result of active migration of the segments. The infection in sheep usually confirmed at meat inspection where the large larval cysts are observed on the mentery, omentum and abdominal organs.

Epidemiology : If untreated, the final host can harbour tapeworms from several months to ayear or more. 2

Treatment : , nitroscanate, mebendazole and fenbendazole are effective against the adult tapeworms . No practical treatment is avaible fort he intermediated hosts. Taenia ovis :

Predilection site: Small intestine

Description : The adult tapeworm is large, measuring 0.5-1.5 m in length. The rostellum has 24-36 hooks, and the uterus in the gravid segment has 2-25 lateral branches on each side. The strobila has a scalloped edge and is often coiled into a spiral. The metacestode form of this tapeworm is found in the muscles of a food animals, such as sheep, goat, camel and reindeer, and they are about the size of 10 by 20 mm.

Final hosts : The adult tapeworm is found in dogs and wild carnivores.

Intermediate hosts : Sheep, goat, camel and reindeer Final hosts : The adult tapeworm is found in dogs and wild carnivores.

Intermediate hosts : Sheep, goat, cattle and pig, some wild animals and some rodents, such as hamster

Geographical distribution : Worldwide

Life cycle : The biology of this species is similar of the biology of T. hydatigena. Dogs and wild canids are infected by consuming the cysticercus in the intermediate hosts. The intermediate host is infected through the ingestetion of cestode eggs that hatch in the intestine. The larval stage, which is called Cysticercus ovis, are mature in about three months, infects the musculature and cysts are usually lpcated in the skeletal muscle, heart, diaphragm and connective tissue. The peratent period in dogs ia around 6-9 months.

Pathogenesis and clinical signs : Heavy infections in young dogs can sometimes cause diarrhoea and ill-thrift. Taenia ovis is of less importance because man can not be infected with the adult tapeworm.

Epidemiology : Adult tapeworms shed three segments each containing 70000-90000 eggs. Dogs can be infected by more than one adult cestode. The thick-shelled eggs can survive 90- 150 days at 10-15°C but survive for shorter periods at higher temperatures. Ruminants are infected by grazing pasture and forages contaminated with dog or fox faeces harbouring eggs of T. ovis.

Diagnosis : Tapeworm infection in dogs is often recognised through the presence of shed proglottids in fresh faeces.

Control : Regular treatment of dogs with an effective will reduce contamination of the environment. Dogs should be denied access to raw sheep and goat meat and carcasses. Treatment : As for other taeniid species.

Taenia pisiformis :

Predilection site: Small intestine 3

Description : The adult tapeworm may be up to 2 m in legth. The rostellum has 34-48 hooks arranged in two rows. Gravid segments are 8-10 mm long and about 4-5 mm broad. The median stem of the uterus has eigth to fourteen lateral branches on each side. The omentum and mezenterium in the intermedited host. Final hosts : Dogs and fox

Intermediate host : Rabbit and hare ( wild rabbit)

Geographical distribution : Worldwide

Life Cycle : The life history of this species resembles that of T.hydatigena and its effects on the final and intermediate hosts are similar. Infection of intermediate host is through ingestion of tapeworm eggs shed by dogs. Ingested eggs hatch in the small intestine of the intermediate hosts and penetrate intestinal wall and pass via the portal system to the liver. The juvenil fo may migrate through tje liver parenchyma and locate in the abdominal cavity after 2-4 weeks, where they develop into cysts ( Cysticercus pisiformis ) attached to the wall of the mesentery and omentum. Cysts can survive the life of the hosts. The final host is infected by ingesting the C. pisiformis. The prepatent period in the dogs is around 6-8 weeks.

Pathogenesis and clinical signs : The adult tapeworms in the dogs usually cause little trouble. Cysticercus pisiformis damages the liver of the intermediate hosts, and , if they numerous, they may kill the intermediate hosts quickly. In heavy infections liver damage can occur in the intermediate hosts as a result of migration of juvenile stages through the liver parenchyma. This can lead to hepatitis and cirrhosis. A form of ‘ hepatitis cysticercosa’ is recognised in rabbits, caused during the wanderings of the oncosphere in the liver.

Infection is usually asymptomatic. In heavy infection intermediate hosts may show emaciation and jaundice.

Epidemiology : there is a high prevalence in hunting dogs.

Diagnosis : Infection of the intermediate hosts is detected through the presence of a single cyste or a cluster of several cysts in the abdominal cavity.

Control : Hunting dogs should be wormed requlary with an effective anthelmintic and should not be fed carcasses or offal from rabbits and hares. Treatment : As for other taeniid species.

Taenia taeniaformis : The adult tapeworm is of medium size, up to 70 cm in length, and is sligthly different from the rest of the genus in groos morphology, for it has no obvious ‘ neck ‘ behind the scolex. The terminal segments are said to be bell-shape, but this is not a reliable differential character. The uterus has five to nine lateral branches. The metacestode , or larval , stage for T. taeniaformis is the strobilocercus, a morphological variation of the ctsticercus, or bladderworm, stage. The name of the metacestode stage of T. taeniaformis is Strobilocercus fasciolaris, which is a small cyst connected with an evaginated scolex by a segmented juvenile strobila. Final hosts : Cat, lynx, stat,fox 4

Intermediate hosts : Mouse, rat, rabbit, squirrel

Life cycle : The metacestode, S. fasciolaris, develops in the liver of intermediate hosts and is infective to cats after about 9 weeks. When the cats ingest the metacestode the scolex atacches to the wall of the intestine, and then the neck and its connected bladderr are digested, and the tapeworm begins to grow in the cat’s intestine. For every strobilocercus that is ingested by the cat, one adult tapeworm will develop in the small intestine of that cat. The prepatent period in the cats is around 6 weeks, and cats can remain infected for up to about 2 years.

Patogenesis and clinical signs : Adult tapeworms are of minör pathogenic significance and infectiona are usually subclinic.

Epidemiology : The rodents are infected by grazing pasture and forages contaminated with cat faeces harbouring eggs of T. taeniaformis.

Diagnosis : Diagnosis depends on the demonstration of proglottdis in the cat faeces.

Control : Control depends on dietary methods that exclude access to the larval stage in the intermediate host. Where practical, cats should be prevented from eating rodents.

Treatment : For adult tapeworms a number of effective drugs are available, including praziquantel, mebendazole and fenbendazole. Taenia multiceps : The adults of T. multiceps are 40-100 cm in length and have a small scolex about 0.8 mm in diameter with four suckers. There is a double ring of 22-32 rostellar hooks. The gravid segments measure 8-12 mm by 3-4 mm and the uterus has 18-26 lateral branches which contain taeniid eggs. The metacestode larval stage ( Coenurus cerebralis ) is readily recognised when mature as a large fluid-filled cyst up to 5.0 cm or more in diamete . It consists of a thin bladder filled with flui , on the surface of which the scolices appear as small white granules. As many as 500 scolies may be found ina bladder. Each head has a rostellum mounted by a double row of 22-32 hooks.

Final hosts : Dog, fox, coyote, jackal and wolf Intermediated hosts : Sheep, goat, cattle, deer, pig, horse and human

Life cycle : The embryonated eggs pass in the feces of the infected dog or other carnivore, either free or contained within the gravid segment. These are ingested by intermediated hosts and the oncosphere liberated in the small intestine. It penetrates the intestinal mucasa, and usually only those which reach the central nervous system continue their development. The cyst will wander around, on or in the brain and spinal cord and is fully formed in 7 or 8 months. The cyst in sheep and goats often persist throughout the life of . The life cycle is completed when the final hosts eat an infected sheep brain or spinal cord.

Pathogenesis and clinical sings : Infection in the final hosts are usually asymptomatic. The coenurus takes about 8 months to mature in the CNS and, as it develops, it causes damage to the brain tissue resulting in neurological disturbances. These cyst can cause pressure atrophy, which may lead to perforation of the skull. When cysts locate in the spinal cord, the resulting 5 pressure can lead to paresis of the hindlimbs. Although an acute form of coenurosis can occur, chronic disease is more frequently identified. Acute disease is likely to occur when sheep are grazed on pasture heavily contaminated with faeces from untreated dogs. The migration of large number of larval stages through the brain can rapidly lead to neurological dysfunction and death. Chronic disease presents as a progressive focal lesion of the brain with signs of neurological dysfunction appearing about 3-6 months from initial infection and is usually seen in sheep of 6-24 months of age. Coenurosis is much less common in cattle.

The cyst or cysts are mainly located in one cerebral hemisphere and occur less frequently in the cerebellum and spinal cord. The growth of cysts within the brain or skull causes pressure atrophy of adjacent cerebral tissue. The migration of the large numbers of immature stages in the brain of lambs can lead to acute meningoencephalitis. In acute cases of coenurosis, pale yelllow tracts are frequently present on the surface of the brain. They are comprised of necrotic tissue with marked cellular infiltration. In chronic coenurosis there nay be compression of brain tissue by the developing cyst and the increased intracranial pressure can result in local softening of the bones of the skull, either above the cyst or in other areas.

Clinical signs depend on the location and size of the cyst or cysts and include circling behavior, visual defects, peculiarities in gait, stumbling, uncoordinated movements, hyperaesthesia or paraplegia. As the infection and animals may become anorexic and lose weight and death may result. The clinical syndrome is often known as grid or staggers in which the animals holds its head to one side and turns in a circle to the affected side.

Epidemiology : This is largely influenced by whether sheep-dogs (shepherd dogs) and stray dogs have access to the heads or spinal cords of infected intermediated hosts. Where livestock, particularly sheep, have access to grazing land that is contaminated with infective dog faeces, then there is a risk of larval migration of the metacestode stage into the central nervous system.

Diagnosis : Often the first sign of tapeworm infection in dogs in the presence of proglottids in the faeces or more frequently the perianal area as a result of active migration of the segments.

Diagnosis of the intermediated hosts may be made symptoms but this should be confirmed by locating the cysts in the brain and spinal cord. The infection in sheep usually confirmed at meat inspection where the large larval cysts are observed on the mesentery, omentum and abdominal organs. Even then others organisms, such as Listeria monocytogenes, Ostrus ovis and louping-ill, should be considered an any evaluation of acute coenurosis. Where cysts are located on the surface of the brain it is sometimes possible to palpate the local softening of the frontal bones of the skull.

Control : This can be achieved by ensuring that dogs, in particular sheep-dogs, do not have accsess to the heads of slaughtered or dead sheep or goats. It is essential that all sheep carcasses are buried as soon as possible. In areas where coenurosis is endemic, the regular deworming of dogs with an effectiveanthelmintic every 6-8 weeks will reduce the contamination into environment and, by breaking the sheep-dog cycle, may lead to eradication of the disease. Fox are not thouht to be an important final host for T . multiceps. 6

Treatment : In dogs, as for other taeniid species. There is no practical treatment of coenurosis in sheep or goat.

Taenia serialis : The adult tapeworm is of medium length , around 20-70 cm, and bears two rows of hooks. The gravid uterus has 1-18 lateral branches and the vaginal sphincter is well developed. The metacestode cyst may be 4-6 cm in size. The development of the coenurus of this species, Coenurus serialis, occurs usually intermuscular connective tisssue, though it is seen time to time in other regions, and especially in the orbit. The numerous scolices in the Coenurus seralis are arranged in lines or strands as the name ‘ serialis’ implies. Final hosts: Dog, fox and other carnivores.

Intermediated host : Rabbit, hare and rarely rodents and man.

Life cycle : Infectionof the intermediated host is through ingestion of tapeworm eggs shed by dogs. The larval form Coenurus serialis is found in the rabbit, usually subcutaneously or intermuscular connective tissue. The final host is infected by ingesting the metacestode stage.

Pathogenesis and clinical signs : Infection is usually asymptomatic in both the final and the intermediated host. No clinical signs reported.

Epidemiology : There is a high prevalence in hunting dogs.

Diagnosis : Infection of intermediated host is detected through the presence of larval stage in tissue.

Treatment : As for other taenid species.

Control : The hunting dogs should not be fed raw carcases and offal from rabbits and hares.

Treatment of cestode infection of dog and cat

Mesocestoides Dipylidium Taenia spp. Echinococcus spp.

Fenbendazole 50mg/kgX3 + Flubendazole 22mg/kg + Mebendazole 50-100mg/kgX2 +

Nitroscanat 50mg/kgX2 + +

(only use dog, 2 days break)

Praziquantel 5 mg/kg + + + + Epsiprantel 5.5mg/(dog)

2.75mg/kg(cat) + + + + 7

Family Mesocestoididae : Adult parasit are found in the small intesine of dogs, cats and wild carnivores. The second intermediated forms (tetrathtyridium or dithyridium ) are found in the peritoneal and pleural cavities or subcutaneous tissue of a wide variety of vertabrate hosts.

Mesocestoides lineatus : The adult tapeworms ranges from 30 to 250 cm in length and up to 3 mm wide. The scolex is largei unarmed and without a rostellum, and the four suckers are elongate and oval. The strobila is thin and narrow, up to 1.5 cm in length. Mature segments are longer than wide and each contains a single set of central reproductive organs. The central genital pore opening on the dorsal surface. The ovary and vitelline glands are bilobed and there are numerous testes. Oncospheres in gravid segments progress fromthe uterus into a paruterine organ. The eggs are oval and measure 40-60 by 35-43 µm.

Predilection site : Small intestine Final hosts : Dog, cat, fox, mink and wild carnivores

Intermediated host : Host 1: oribatid mites. Host 2 : birds, amphibians, reptiles, small mammals, fowls, dogs and cats

Life cycle : The life cycle has not fully eluciated but is indirect and consists of two intermediated hosts and one definitive host. Initially, the egg, contains oncosphere is ingested by a coprophagus arthropod and develops into cysticercoid. The artropod is ingested by a second intermediated host such as a small rodents, bird, lizrd, snake, or frog. Within the peritonela cavity of the second intermediated host, the second larval stage develops into tetrathyridium. The final adult form develops when the second intermediated host is ingested by the definitive host. Dogs and cats can start to shed tapeworm segments in faeces as early as 3 weeks after infection.

The complete life history of the genus Mesocestoides has yet worked out. The life cycle requiest two intermedaited hosts. A cysticercoid is produced in the first intermediated host which, when eaten by second intermediated host, larval stage a tetrathyridium; this may remain as an encapsulated form for sometime. The tetrathyridium is located in the peritoneal cavity in reptiles and mammals ( including dog and cat ) and in the lungs in birds.

Pathogenesis and clinical signs : Adults tapeworms are minor pathogenic significance and infections are usually subclinical. Tetrathyridium lives in the serosal cavities of their intermediated hosts, which include amphibians, reptiles, birds and rodents. Dogs and cats can also habour tetrathyridium in their peritoneal cavities. Mammals (including dogs and cats ), usually involved in cycle as final hosts, can in some cases act as intermediated ones, harboruing tetrathyridia of several (but not all ) species belonging to the genus Mesocestoides, incuding M. vogae (syn. M. corti) , M. lineatus by ingestion of a first larval stage within an arthropod or of tetrathyridium within a second intermediated host. In these cases, the metacestodes penetrates the intestine wall, invades the peritoneal cavity and a systemics infection occurs, expanding to many organs and tissues. Tetrathyridia have the unique ability among the metazoan parasites to undergo asexual reproduction by budding or binary fission and adapt to low-oxygen environments within body cavities and organs. Active proliferation of tetrathyridia in the peritoneal cavity of dogs or cats causes peritonitis. These larvae can 8 cause depression, ascites, abdominal distention , peritonitis, anorexia/ weigth loss, pyrexia, poor hair coat, tachypnea,dyspnea and, occasionally, death in dogs and other definitive hosts. Thoracis involvement of tetrathyridiosis seems to be an extremely rare findings in dogs and cats. Clinical signs are often insidious in onset, intermittent, and progressive, but may be absent altogether. Clinical signs before diagnosis may be absent, they can be severe and fatal.

In all cases of tetrathyridiosis in dogs and cats, generally, the clinical symptoms had started several months up to a year before diagnosis. Generally, infected dogs and cats appear healthy and harbour relatively few larvae, or they may present with abdomimal distension resulting from ascites and larval parasites in their abdominal cavity. Subclinical infections are often diagnosed during laparotomy (i.e., ovariohysterectomy ) and necropsy.

Result of count blood cells (CBC) include mild nonregenerative anemia, with on red blood cells (RBC) count of 4.69X10 6 /µl , hemoglobin concentration of 11.9 g/dL, hematocrite 34.8 %, and reticulocyte count of 56.28 / µl.

The dogs and cats have mild nonregenerative anemia, monocytosis, neutrophilia, and thrombocytosis. These abnormalities are attribuated to chronic inflammation and reactive thrombocytosis. Serum chemistry findings are often unremarkable in dogs with peritoneal larval cestodiosis ( tetrathyridiosis), although hypoprotenemia is observed into peritoneal cavity secondary to inflammation.

In abdominal radiographs, there is increased soft tissue opacity with loss abdominal detail and mass effect on small intestine loops that were displaced peripherally. Ultrasound examination revealed marked ascities, with hyperchoic particles and multiple cystic structure within the abdomen.

At postmortem examination, grossly, lesions of peritoneal tetrathyridiosis in dogs abd cats are confined to the abdominal cavity and include ascites with severe fibrinous peritonitis, serosal adhesions, and cyst formation. The cysts rage from several milimeters to 2-3 cm in diameter. The cysts have a smooth surface with whitish colour, and they contain transparent liquid and tetrahyridium. Tetrathyridia are usually found free in peritoneal cavity particular, and are sometimes attached to the serosal surfaces; less frequently they they are present şnside the organs like chronic granulomatous masses.

The abdominal fluid is generally beige to yellow, pink, red or dark red colour, and hazy. Numerous round to angular refractile clear to golden-brown colour structuresi 20-30µm in diameter, are observed in a background of abundant dense blue amorphous cellular debris. Internally, the structures appears empty, or contained concentric rings, or have a grpe-like vesicular apperance. The structures are compatible with developing and mature calcerous corpucles, organelles specially found in cestode stomal tissue.

Diagnosis : When the adlut tapeworms are found in the small intestine ın the final hosts, diagnosis depens on the demostration of segments or individual eggs in the faeces. 9

Diagnosis of tetrathyridiosis in dogs and cats is challenging because there no parasitic stages passed in the faeces and no serologic tests. Diagnosis of tetrathyridiosis in dogs and cats is based on clinical symtomps, ultrasonographic findings and cytology of the peritoneal fluid. However, diagnosis of this infection is often an incidental finding during on laparatomy. It should be noted that negative fecal examination results are typically in dogs with tetrathyridiosis, possbily indicating that ingestion of the first intermediate host is more common than ingestion of the second intermediate host.

Treatment : Praziquantel is common used to treat adult tapeworms in the small intestine, and used not to be efffective against tetrathyridiosis in dogs and cats. In peritoneal tetrathyridiosis, treatment with fenbendazole has proved more efficacious than treatment with praziquantel. Fenbendazole is effective against tetrathyridium infection in dogs at 100 mg / kg per os, twice daily for 28 consecutive days. Ultrasound is also useful for therapy management and follow-up. This is an important feature of therapy management, in that the observe in flammatory response 20 days after diagnosis, likely due to dying larvae, indicated the need for antibotic treatment.

Closed peritoneal lavage, where a large bore needle or catheter is inserted into peritoneal cavity to drain fluid and parasites, is most useful when parasites are found free in the peritoneal cavity. However , when parasites are sequestered in pockets or cycts, it may be necessary to located and drain cysts by guided ultrasound. In cases ( larval invasion of tissue, massive fibrinous adhesion ), where lavage is impractical , it may be necessary to surgically remove parasites and associated tissue.

Our impression with lower doses of fenbendazole, or given fenbendazole for shorter periods of time, were more likely to have positive peritoneal tetrathyridiosis after treatment. The utility of giving high, prolonged doses of fenbendazole, or using fenbendazole at any dose in combination with surgery / lavage, to achieve clinical improvement was confirmed by the highly significant influence of treatment on survival.

Prognosis : In dog and cat, tetrathyridiosis is a life-threatening disease with a guarded prognosis; survival at 6 months and 1 year post-diagnosis were only 72 % and 60 % , respectively.

Family Dilepididae : These cestodes are smaller than most of taeniids and anoplocephalids, and they usually have a well-developed rostellum with several rows of hooks; the suckers may also be armed. The intermediated hosts are invertabrates, carrying cysticercoids.

Diplydium caninum :

Predilection site : Small intestine Description : This species is often called the double-pored or cucumber seed tapeworm. The adult tapeworm can grow to a legth of 50-75 cm. The scolex of this tapeworm is armed and consists of a prominent proboscis covered with rearward- facing rose-throrn-like hooks. Each mature proglottid which is oval and cucumber seed in shape contains a double set of reproductive organs, with a pore opening on each margin. There about are 200 testes in the mature segments distributed uniformly between the excretory canals . The uterus is first 10 reticular in structure and finally , in the gravid proglottids, break up into egg capsule ( 120-200 microns ), each containing 20 – 50 eggs. The indivual eggs measure 25-50 microns in diameter, and small, almost spherical with vitelline membrane, dark-brown to yellowish. This egg contains hexacanth embryo ( oncosphere ). Final hosts : Dog, cat, fox ; rarely man

Intermediated hosts : Fleas ( Ctenocephalides spp., pulex irritans ) , lice ( Trichodectes canis )

Life cycle : The newly passed segments are active, and can crawl about on the tail region of the animals. The oncospheres are contained in egg packets or capsules, each with about 20- 50 eggs, and these are either expelled bu the active segment or released by its disintegration. Intermediated hosts become infected by ingesting the eggs, which contains oncosphere, and oncosphere travel to the abdominal cavity where they develop into cysticercoids. All stage of the biting louse can ingest oncosphere, but the adult flea, with its mouthparts adapted for piercing, can not do so, and infection is only acquired during the larval stage, which has chewing mouthparts. The final host is infected by ingesting of the or louse containing the cysticercoids. Development to patency, when the fist gravid segments are shed, takes about 3 weeks.

Pathogenesis and clinical signs : Diplydium caninum is commenest tapeworm of dogs and cats. It is not highly pathogenic, and the main effect is a puritis caused by segments on the perineum. They shed segments, which, active as they crawl actively from the anus, mat cause some discomfort, and a useful sign of infection is excessive gromming of the perineum. It has been suggested that infected dogs form the habit of rubbing the anus along the floor, but impacted anal glands are a more common cause of this behaviour.

Epidemiology : Diplydium caninum infection is very common and, being dependent on the continuous presence of ectoparasites for its local endemicity, it ismore prevalent in neglected animals, though infestations are also seen in well kept dogs and cats.

Diagnosis : Often the first indication of infection is the presence of a segment on the coat around the perineum. If the segment is freshly passed, preliminary identification may be made oh tje elongate shape, and the double genital organs, which may be seen with a hand lens. If it is dried and distorsed it will be necessary to break it up with mounted neddles in water, where the the egg capsules are easily seen under the microscope, thus differentiating the segmeny from that of Taenia spp. , which contains only numerous single oncospheres.

Teratment – Control : In this infection, tratment and control must be instituted together, for it is clearly of no value to elinate the adult tapeworm while leaving a reservoir in the animal’s ectoparasites. Hence, administration of , such as praziquantel, should be accompanied by the use of insecticides.

Diplopylidium nölleri : This tapeworm occurs in small intestine in the cat and dog. Two intermediated hosts are involved: firstly, various beetles and secondly, a reptile or small mammals. 11

Joyeuxiella pasqualei : Joyeuxiella pasqualei is a tapeworm commonly found in small intestine of cat, dog, fox, wolf and other wild carnivores. The scolex of the tapeworms bore four suckers and a rostellum. The adult tapeworms attach to the host intestinal mucosa by a rostellum , which carries over seven ( usually 14 yo 18 ) rows of thorn-like hooks. The gravid proglottides contain only one egg (40x30 microns) in each egg capsule.

In life cycle ; the cysticercoids develop in coprophagous beetles, intermediated hosts, and reptiles , lizards and small mammals serve as paratenic hosts. Most infected animals do not any show any clinical signs. However, the attachment of J. pasqualei to the intestinal mucosa migth cause marked injury associated witg villous necrosis.

Treatment ; as for other taenid spp

Amoebotaenia cuneata ( A. sphenoides ) : This small tapeworm is found in the small intestine of chichens and turkeys. They are 2 to 4 mm in length, and it is roughly triangular in shape. The scolex is 200 to 400 microns in diameter and the armed rostellum bears a single row of 12 to 14 hooks.

In life cycle ; earthworms have been incriminated as intermediated hosts fort this species. Approximatelly 4 weeks are required fort he cysticercoids to become infective in the earthworm and 4 weeks fort he mature tapeworm to develop in the chicken.

Generally considered to be low pathogenic significance.

Choanotaenia infundibulum : This tapeworm occurs in the small intestine of chickens, turkeys, pheasant and other wild birds. They may attain a legth of 20 cm and a width of 1 to 2 mm. Each segment is wider posteriorly, giving the margin of the tapeworm a ‘ saw-edge’ appearance. Eggs measure about 45x55 microns and possess a long distinctive filament.

In life cycle ; a number of insects ( beetles, house fly, grrasshopper ) will serve as intermediated hosts.

Diagnosis : Although gravid segments are passed in the faeces,diagnosis is usually made at necropsy.

Family Hymenolepididae : These small to medium-size tapeworms are of minor veterinary importance. Members of this family, which have a characteristically slender strobila with a conical rostellum, infect birds, humans and rodents. The intermediated stage is a cysticercoid present in an arthropod host.

Hymenolepis cantaniana : A slender tapeworm, reaching a length of up to 2 cm. The rostellum is rudimentary and the suckers are unarmed. This tapeworm is located in the small intestine of chicken, turkey, pheasant, quail and other fowl. Beetles have been incriminated as intermediated hosts fort this species.

Hymenolepis carioca : This is aslender thread-like tapeworm reaching a length of up to 8 cm. The scolex is unarmed. The proglottids number 500-1100 and are broader than they are long. This species is found in the small intestine of chicken, turkey, pheasant, quail and other fowl. The intermediated hosts are dung and flour beetles. 12

Hymenolepis lanceolata : A slender tapeworm reaching up to 15-20 cm in length. The proglottids are much wider than they are long. This species is found in the small intestine of duck and goose. The intermediated hosts are aquatic copepod crustaceans.

These tapeworms have moderate to heavy infections, which can induce a catarrhal enteritis and necrosis of the mucosa. Heavy infection can be fatal. Large numbers of tapeworms may cause diarrhoea.

Fimbriaria fasciolaris : This is not common tapeworms. The adult parasite vary in length from 2.5 cm up to about 40 cm. The scolex is samll with 10 hooks but the anterior of the body possesses a’ pseudoscolex ‘ ( a folded body expansion) for attachment to the host. The presence of this expansion aids diagnosis. This species is found in the small intestine of chicken, duck, goose and wild anseriform birds. The intermediated hosts are copepods.

Rodentolepis : Parsites of rats and mice and includes the dwarf tapeworm ( Rodentolepis nana ) and rat tapeworm ( Rodentolepis diminuta), which can infect humans.

Rodentolepis nana ( Syn; , Vampirolepis nana ) : The tapeworm is small, 2.5-4 cm in length, and has a characteristiclly slender strobila with about 200 segments. The scolex has four suckers and is armed with a recractale rostellumbearing a single row of 20-30 hooks. The genitalis are single and the segments are wider than they are long. Eggs are small, round or oval in shape and measure 44-62 by 30-55 microns. They are colourless with a smooth shell and contain a lemon-shaped embryophore with protruding polar plugs that bear long fine undulated filaments. The embryo has three pairs of small hooks. Predilection site : Small intestine Final hosts : Rat, mouse, human and primates

Intermediated hosts :Flour beetles or fleas

Life cycle : The life cycle is direct. The cysticercoids develop in the villi of small intestine of the final hosts and then emerging to develop to the adult tapeworm in the intestinal lumen. Otherwise flour beetles or fleas can serve as intermediated hosts.

Pathogenesis and clinical signs : Infection in laboratory rodents are relatively uncommon and usually asymptomatic, although heavy infections can cause weigth loss, vomiting and occasinally obstruction of the intestine. Heavy infections in humans mat cause enteritis, anorexia, and anal pruritis.

Epidemiology : Internal autoinfection occurs humans, but infection in rodents usually involves an intermediated host. Under conditions of poor hygiene infected rodents will contaminated food with their faeces, leading to human infection. In additon, such as environment will support the intermediated host. Human prevalence is highest in children.

Rodentolepis nana is of peripheral veterinary importance in that it is a common tapeworm of humans and of laboratory and wild rodents. This is only species of tapeworm for which an intermediated host is not required. Diagnosis : Identification of the eggs in faeces or adult tapeworms in the intestine. 13

Treatment : Praziquantel 5-10 mg/kg repeated in 10 days may be used.

Control : In laboratory colonies of rodents, eradication depens onstrict hygiene and elimination of potential intermediated hosts.

Rodentolepis diminuta ( Hymenolepis diminuta ) : A small tapeworm, about 20-60 mm in length. The rostellum does not possess hooks. The eggs are larger than those of R. Nana, measuring about 60 µm, and the outer membrane is darker and may be striated.

Predilection site : Small intestine

Final hosts : Rat, mouse, and human

Intermediated hosts : Larvae, nymphs and adults of various species of moths, cockroaches, fleas, flour beetles and milipedes

Life cycle : Their eggs are passed in the faeces. The oncosphere hatches in the gut of intermediated hosts and form a cysticercoid develops in the body cavity. When ingested by a final host the larval form develops to mature tapeworm.

Pathogenesis nad clinical signs : Similar to R. nana. Infection of human is less likely to occur.

Diagnosis : Diagnosis is made by finding the eggs or segments in the faeces.

Treatment and control : Similar to R. nana.

Family Davaineidae : These are mainly parasites of birds. These tapeworms usually have rows of hooks on both rostellum and suckers. Egg capsules replace the uterus in this family. The intermediated form is a cysticercoid.

Davainea proglottina : This tapeworm is the most pathogenic cestode of poultry and is quite small, never attaining a length of more than 4mm. It consists of a scolex and only four to nine segments. The rostellum bears 80-100 hooks, arranged in a double row, and suckers bear a few of small hooks. Eggs are located singly in capsules in the gravid proglottids. Predilection site : Small intestine

Final hosts : Chicken, turkey, pigeon and other birds.

Intermediated host : gastropod molluscs such as Agriolimax, Arion, Limax

Life cycle : Gravid proglottids are shed in faeces and eggs are ingested by intermediated hosts, in which develop to the cysticercoid form after about 3 weeks. Follwing ingestion of the mollusc by final host, the cysticercoid develop into adult tapeworms in about 2 weeks.

Pathogenesis and clinical sings : This is the most pathogenic of the poultry cestodes, the doubly armed scolex penetrating deeply between the duodenal villi. Heavy infections may cause haemorrhagic enteritis and ligth infections retarted growth and weakness. Moderate infections can lead to reduced weight gain, inappatence and lowered egg production. Large numbers of parasites may induce emaciation and dyspnoea an even be fatal. 14

Epidemiology : Infection can be common in free-range fowls as suitable intermediated hosts are often available. Young birds tend to be more severaly affected than older fowls.

Diagnosis : This is best achieved at necropsy through microscopic examination of mucosal scrapings from the duodenum and anterior small intestine.

Raillietina : Species of this genus are found in the small intestine of chickens and turkey and other fowls with the cysticercoid intermediated stage, depending on the species, in ants or beetles.

Raillietina cesticellus : A small tapeworm that can reach around 10-14 cm in length, butis often much shorter at about 4-5 cm long. The broad scolex is large and the rostellum wide. The unarmed suckers are not prominent and the rostellum is armed with several hundred small hamer-shape hokks arranged in a double row. The gravis proglottids contain several thin-walled egg capsules, each housing a single egg. Egg are spherical to slightly ellipsoidal and measure approximately 75 to 90 µm. They have athick smooth Shell and contain a oncosphere. Eggs are shed only after the gravid proglottids or the egg capsule disintegrates.

Raillieatina echinobothrida : Tapeworm of this species may be up yo 20-25cm in length, and simialar in shape to R. tetragona. The suckers are circular and armed with several rows of a small hooks and the rostellum is well endowed with two rows of around 200 hooks ( these features enable it to be distinguisned from R. tetragona ). A ‘neck’ is absent behind the scolex.The gravid proglottids contain multiple fibrous-walled egg capsules, each housing several eggs ( around 6-12 eggs).

Raillietina tetragona : Often the largest tapeworm aching around 20-25 cm in length. The scolex is smaller than of R.echinoborthrida and the ‘neck’ is quite prominent. The oval suckers are lightly armed with several rows of fine hooks and the rostellumbears one or sometimes two rows of aronud 100 hooks. The gravid proglottids contain multple fibrous-walled egg capsules, each housing many eggs. Eggs measure approximately 25 by 50 µm. Raillietina tetragona has a large number of egg capsules in gravid proglottid than either R. cesticillus and R. echinoborthrida.

Predilection site : Small intestine Final hosts : Chicken, turkey and other fowls

Intermediated hosts : Ants, house flies, and various genera of beetles

Life cycle : Gravid segments are passed in faeces and eggs are ingested by various intermediated host, and the oncosphere hatches from the egg , and then changes into a cysticercoid in the body cavity. Following ingestion by the final host the activated cysticercoid attaches to the mucosa of the small intestine. The prepatent period is around 2-3 weeks.

Pathogenesis and clinical signs : Raillietina echinobotrida is more pathogenic than either R. tetragona and R. cesticillus . In heavy infection, the embedded scolices of this tapeworm large caseous in the subserpus and muscular layers of the wall small intestine. These lesions in the intestine are similar to those associated with avian tubeculosis. Other tapeworms can induce a catarrhal enteritis. 15

Epidemiology : Young birds are usually more susceptible to infection than adults. Infection rates depend on the availabilty of the intermediated hosts. Eggs are reasonably resistant to environmental conditions and will survive for several months.

Diagnosis : This is best achieved at necropsy through microscopic examination of mucosal scrapings from the duodenum and anterior small intestine.

Treatment of chicken cestodes : Flubendazole 600 ppm X 7 days , fenbendazole 180 ppm X 6 days, praziquantel 1 X 10 mg / kg peros