Retour au menu Epizootiology of camel contagious ecthyma in Eastern Sudan A.I. Khalafalla 1* M.E.M. Mohamed 2 Key words Summary Dromedary - Contagious ecthyma virus - Free-ranging camels in Butana, Kassala and the Blue Nile areas of the Sudan Parapoxvirus - Epidemiology - Season - were surveyed for the occurrence of camel contagious ecthyma (CCE) Sudan. between 1992 and 1994. Thirty-eight herds were found to be affected with the disease. Clinically the pox-lesions first appeared on the lips of affected animals as small papules and later developed into scabs and fissured crusts. PATHOLOGIE INFECTIEUSE communication All CCE cases occurred in young camels up to 3 years old and 97.8% of them were in camel calves less than one year old. The mean morbidity and mortality rates in calves less than one year were 60.2 and 8.8%, respectively, while the mean fatality case rate was 13%. The disease had a marked seasonality associated with rainy season and camel skin abrasion caused by eating thorny Acacia trees. INTRODUCTION MATERIALS AND METHODS The parapox virus, responsible for camel contagious ecthyma Study area (CCE), has only recently been identified (1). Formerly it was thought to be a form of camel pox (CP) since clinical symptoms of It consists of the Butana plains which lie between the main Nile, both diseases were similar (3). the Blue Nile and the Atbara River (Eastern part of Sudan). Areas South and South-West of Kassala as well as East of the Atbara CCE has been reported in Mongolia (4), Kenya (12), Kazakhstan River were also included in the survey (figure 1). Camel herds and Turkmenistan (3) and Somalia (10). In the Sudan the disease originating from the Blue Nile area were investigated as well at has been recently reported and is believed to have existed for Central Butana during the rainy seasons. Trees commonly found years under the names Abu Shalambo in the Western region (2) in the study area consisted of Acacia mellifera, A. nubica and and Al kolate in the Eastern region (8). A. nilotica (1). In addition, the Blue Nile has the following species: A. laeta, A. albida and A. polyacantha (6). Acacia tree Search of the literature reveals very few information on the distribution in the Sudan is shown in figure 2. epizootiology of CCE. The present work has been undertaken to follow-up CCE outbreaks in order to gain more information on Study animals some epizootiological features of this poorly studied camel disease. The investigated camel herds belonged to many tribes including Shukriya, Rashaida, Lahawiyin, Bawadra, Musallamiya, Ruffaa, Kawahla and Arakiyin. The camels were of the Arabi and Diaili 1. Department of Virology, Central Veterinary Research Laboratories, PO Box (pack camels), Annafi and Bishari (riding camels) breeds. Herds 8067, Elamarat, Khartoum, Sudan were kept under different management and husbandry systems, 2. Department of Preventive Medicine and Veterinary Public Health, Faculty of namely nomadism, semi-nomadism or agropastoralism. Veterinary Science, University of Khartoum, PO Box 32, Khartoum North, Sudan * Present address: Department of Microbiology, Faculty of Veterinary Science, Generally, the Rashaida nomads spend the rainy season (July- University of Khartoum, PO Box 32, Khartoum North, Sudan October) around Kassala city and in Central Butana. In the dry Revue Élev. Méd. vét. Pays trop., 1997, 50 (2) : 99-103 99 Retour au menu Epizootiology of came1 contagious ecthymain Sudan u A. nilotica, A. albida Figure 2: map of the Sudan showing the distribution of some Acacia spp. Source: modified from Elamin, Forest Research Figure 1: map of the Sudan showing the area of study. Institute, Bull. No. 2, 1976. season(November-June), some of them move southwardup to sex of the affected animalswere collected.Herders’ accounts of Doka area,350 km Southof Kassala,few migratenorthward up to the diseasehistory and progressof symptomswere alsoobtained. Gash Delta and others crossover to the Red Sea toast around Skin biopsiesor scabswere collectedfrom affected animalsfor Sawakin and Toker (400 km North East of Kassala)to take laboratoryconfirmation of preliminarytentative diagnosis. advantageof range developingas a result of the winter rains (1). The Shukriya, Lahawiyin, Bawadra and Mussalamiya stay in Luboratory investigation Butana in the rainy seasonand move during the dry season towardsthe Atbara River basin.A significantproportion of these Ten percent suspensionswere preparedfrom skin biopsiesor tribesas well as someof Rashaidacoordinate their movementsto scabsin phosphatebuffered saline (PBS). After light centrifugation coincidewith the harvest season(January-March) thus using the one drop of eachsample was placed onto a separatecarbon-coated trop residuesin the rain-fed agriculturalschemes of Gedarefarea grid. After stainingwith 2% phosphotungesticacid the grids were (1). Ruffaa, Kawahla and Arakiyin tribes of the Blue Nile area dried andexamined by electronmicroscopy. spendthe dry seasonat rain-fed agriculturalschemes in the area and move to the North towardsButana plains in the rainy season to usefree rangepasture. WRESULTS The came1population in the study area has been estimatedat 750,000,which represents20% of a11Sudan camels (13). CCE clinical features Fifteen came1herds were visited monthly betweenMarch 1992 Initially small nodulesappeared on the lips of affected animals and June 1993 in connectionwith the French-SudaneseCame1 followed in most caseswith swellingof the,face and sometimes ResearchProject. The aimof thisproject was to studythe husbandry the neck (figure 3). Affected animalswere ataxic and off-food. and productionparameters of camelsin Butana area (1). During Papules and vesicles appeared later and within a few days eachvisit to the study areaadditional 15 to 20 herds,which were developedinto thick scabsand fissuredtrusts (figure 4). Lesions not coveredby the abovementioned project, were alsoinvestigated. occurred sometimeson the face, eyes and nares and in severe BetweenJuly 1993and December 1994 the study areawas visited casesin the gingiva, dentalpad and tongue.‘Deathwas probably eight times in responseto reports of pox or pox-like disease due to starvation causedby the inability of affected animalsto outbreaks.During the whole period of the study approximately grazeor suckletheir dams.Healing occurred within 20-30 daysin 20,740camels in 305 herdswere surveyed. mostcases, but sometimesthe courseof the diseaseextended up to threemonths. Epizootiological investigation Disease incidence During each field visit the investigatedherds were located and data on CCE occurrence were ‘collected. Sick animals were A numberof 305 came1herds were surveyed for CCE occurrence. carefully examinedfor clinical symptoms,site and type of lesions This numberrepresented approximately 3% of the whole came1 and generalanimal health. Additional dataconcerning the ageand herds in the study area. Thirty-eight herds were found tolbe 100 Retour au menu Epizootiologie de l’ecthyma contagien du dromadaire au Soudan Figure 4: came/ contagious ecthyma: a close-up view of the af- fected came1 face show@ scabby lesions around the lips, nos- trils and eyes. Note the lower lip is pendulous. Figure 3: came/ contagious ecthyma: acutely affected Young Although no mention was madeof the morbidity and mortality came/ showing swelling of the head and Upper part of the neck. ratesin mostprevious reports on CCE, Munz et al. (12) reported no deathsdue to the disease,Dashtseren et al. (4) reported a mortality of O.l-0.6% calculatedfrom the total numberof Young andadults. affected with the disease(herd incidence rate in the sample: Khalafalla et al. (8) reported a total mortality rate of 17.5% 12.5%). The diseasewas recordedin 35 of theseherds (92.1%) (34.4% in calves lessthan one year old) in a CCE outbreak in during the rainy season(July-October) and only 3 affected herds Butana area of Eastern Sudan in 1991. They attributed the (7.9%) were recordedin the winter season(November-March), relatively higher mortality rate to the addedeffects of starvation while no diseaseoutbreak was seen in the sumrnerseason (April- andlack of food in the seasonpreceding the time of that outbreak. June). Dashtserenet al. (4) attributeddeaths caused by CCE in Mongolia to fatigueand exhaustion of affectedanimals. Table 1 showsthe morbidity and mortality rates and the fatality caserate of camelsaffected with CCE in Central Butana and Most camelsin the study areafed during the dry seasonon harvest Kassala,Southern Butana and the River Atbara, and the Blue Nile remains(Sorghum stalks) of the rain-fed agricultural schemes. areas.The meanmorbidity rate in came1calves less than oneyear During the rainy seasonanimals fed mainly on free rangepasttire old in the three geographicalareas was 60.2% and the mean in Butanaplains. However, early in the rainy season(June-July) mortality rate was8.8%, while the meanfatality caserate was 13%. and due to the spoilingeffect of the rains on the Sorghumstalks camelswere obliged to leave theseschemes and browseAcacia Age and sex distribution treesin the areauntil adequategreen grasses developed in Butana plains.At that time of the year CCE outbreaksoccurred. A factor The age distributionof 280 CCE caseswith 34 deathsis shownin responsiblefor this seasonalitycould be lip skin abrasionresulting table II. Al1 casesoccurred in Young animalsup to 3 years old. from eating thorny Acacia trees at this time of the year when no Most of the affectedanimals (70.7%) were in the agegroup 7-12 other sourceof food wasavailable. BuEhnev