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Investigations on new epizootic described on camels (Camelus dromedarius) in Ethiopia

Roger F., Libeau G., Sechi L.A., Grillet C., Yigezu L.M., Diallo A.. 2000. In : International Conference on emerging infectious diseases (ICEID 2000), Atlanta (USA), July 16-19, 2000. s.l. : s.n., 1 p.. International Conference on Emerging Infectious Diseases, 2000-07-16/2000-07-19, Atlanta (Etats-Unis).

An epizootic disease has substantially affected the camel population in Ethiopia in 1996. It was an acute febrile infection characterised by respiratory syndrome, highly contagious, with elevated morbidity and low and medium mortality rates, especially following an antibiotic treatment. In a period less than 12 months, the disease was registered in most camel rearing areas of the country The morbidity rate notified was over 90% and the mortality rate vaned from 5 to 70%. The appearance of similar symptoms with a rinderpest-like disease as well as the high prevalence of the Peste-des-Petits-Ruminants (PPR) in caprine and ovine in the epidemic area, its remarkably rapid spread and its pathology, has prompted us to search for a viral disease and particularly for morbillivirus as primary etiologic agent. Detection of 1. PPR virus (PPRV) antigen by immuno-capture test; 2. PPRV genome by RT-PCR and 3. PPR antibodies have been carried out and displayed positive results. Sequencing of amplified fragments are in progress and preliminary results showed genetic proximity with PPRV strains. A competitive ELISA test for PPR has been applied on Sam samples from three epidemiologically defined regions. We observed an increase in the sero-prevalence rates from the first group (non affected) up to the third (sampling one month after the end of disease) with intermediate results for the second group including sick animals. Moreover, bacteriological works have been carried out handling different culture media. Streptococcus equi subsp. equi strain has been isolated from bone marrow of camels. It was apparently the first isolation of the equine Strangles agent from camelids. It is assumable that the outbreak could have been initiated by a morbillivirus closely related to the PPR virus. The virus might have an immuno-suppressor consequence which might have favoured the pathogenicity of the secondary bacterial infections that had been effectively treated by antibiotics and reduce the mortality rate. However, considering the specificity of Strangles on equine, which is notably a highly contagious disease, the exact role of S. equi equi remains to be evaluated.

Mots-clés : dromadaire; maladie des animaux; infection; test elisa; épidémie; Éthiopie

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