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Freie Universität Berlin (2014)

An Epidemiologic Study of Canine Echinococcosis and Livestock Hydatidosis in the Sudan

Abass, Naglaa Abd El Hakeem

Titre : An Epidemiologic Study of Canine Echinococcosis and Livestock Hydatidosis in the Sudan

Eine epidemiologische Studie über Hundeechinokokkose und Hydatidose beim Vieh im Sudan

Auteur : Abass, Naglaa Abd El Hakeem

Université de soutenance : Freie Universität Berlin

Grade : Doktors der Veterinärmedizin 2014

Résumé
Echinococcus granulosus infections are a major public health problem in livestock-raising regions worldwide. Cystic echinococcosis is endemic in some areas of the Sudan, nevertheless, its presence in other parts of the country is basically unknown. In this project, a retrospective cross-sectional study was conducted to update the CE prevalence and to investigate epidemiological factors associated with the infection in sheep, goats, cattle and camels slaughtered at urban and rural abattoirs of five regions in the Sudan (Khartoum, Wad Madani, Tamboul, Elobeid and Senga). A total of 1,991 domestic ruminants (535 sheep, 291 goats, 735 cattle, 430 camels) were examined for the presence of E. granulosus hydatid cysts in the period from July 2011 to January 2012. The prevalence of cystic echinococcosis (CE) was 25.3% (109/430, 95% CI 21.30-29.74%) in camels, 1.4% (11/735, 95% CI 0.74-2.67%) in cattle, 0.3% in sheep (2/535, 95% CI 0.04-1.34%) and 0.3% (1/291, 95% CI 0.00-1.90%) in goats. 92.7% , 2.7% and 4.6% of the camels were found infected only in the lungs, only in the liver or in both, liver and lungs, respectively. Overall, 256 hydatid cysts were collected from a total of 109 infected camels. 121 (47.3%) were fertile, 50 (19.5%) sterile and 53(20.7%) calcified and the highest percentage of fertile cysts was recorded in the lungs. Hydatid cyst prevalence was significantly higher in older and female camels. Of 17 cysts recovered from infected cows, 12 (70.6%) were fertile, 2 (11.8%) sterile and 1(5.9%) calcified and cyst prevalence was significantly higher in female cattle. Molecular analysis of both sub-multiplex PCR (Sub-mPCR) and sequencing of the mitochondrial marker coxI performed on cyst material from 62 camels and 7 cattle demonstrated that 92.7% of the study animals were infected with E. canadensis (G6) and 2.9% with E. ortleppi (G5), while 4.3% of the isolates could not be genotyped. Another emphasis of this thesis was the assessment of the prevalence of canine echinococcosis and potential risk factors associated with the acquisition of the disease in owned dogs. Between July 2011 and January 2012, a cross-sectional survey was conducted in the same areas where the status of hydatidosis in slaughtered animals was determined. Fecal samples from 143 dogs (63 domestic and 80 stray dogs) were examined for E. granulosus infection by direct microscopic examination after combined flotation and sedimentation method followed by multiplex PCR of mitochondrial genes for positive taeniid eggs samples. The combined flotation and sedimentation technique revealed taeniid eggs in the fecal samples of 33 dogs (23.1%, 95% CI : 16.4-30.9%). Multiplex PCR revealed that 13 out of 143 dogs examined in different sites in the Sudan were infected with E. granulosus and 3 from those 13 had co-infection with E. granulosus and Taenia spp.. 8 household (12.7 %) and 5 (6.25 %) stray dogs were infected with E. granulosus corresponding to a total prevalence of 9.1% (95% CI : 4.9-15%). Since no studies have been conducted so far in the Sudan to evaluate the risk factors related with canine echinococcosis, the present survey focused on investigating these potential factors in owned dogs based on responses to a questionnaire administrated to dog owners. Significant risk factor for a copro-positive owned dog was associated only with de-worming. High proportions of E. granulosus were recorded in younger, male, guarding and pet dogs. Higher prevalences of canine echinococcosis were also detected in free roaming dogs and dogs that were kept outside houses and fed on raw meat.

Mots clés  : Dogs ; cattle ; camels ; sheep ; goats ; Echinococcus granulosus ; cystic echinococcosis ; epidemiology ; polymerase chain reaction

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