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International audience; The circulation of West Nile virus (WNV) in horses was investigated in the Southwest Indian ocean. In 2010, blood samples were collected from a total of 303 horses originating from Madagascar, Mauritius, Reunion and the Seychelles and tested for WNV-specific antibodies. An overall seroprevalence of 27.39% was detected in the Indian Ocean with the highest WNV antibody prevalence of 46.22% (95% CI: [37.4–55.2%]) in Madagascar. The age and origin of the horses were found to be associated with the WNV infection risk. This paper presents the first seroprevalence study investigating WN fever in horses in the Southwest Indian Ocean area and indicates a potential risk of infection for humans and animals. In order to gain a better understanding of WN transmission cycles, WNV surveillance needs to be implemented in each of the countries.

A population of approximately 70 000 rusa deer (Cervus timorensis russa) represents the most important mammal species reared for food on the island of Mauritius, being the main source of red meat for the local population. However, very limited information is available on the circulation of pathogens affecting the productivity and health of this species. To produce baseline data on the circulation of infectious pathogens in rusa deer under production, a serological survey and/or direct pathogen detection for six selected infectious diseases was undertaken in 2007 in a sample of 53% of the herds reared in semi-free-ranging conditions in hunting estates. Seropositive results were recorded for Johne's disease with an indirect ELISA test (1.7%, n = 351), heartwater with an immunofluorescence antibody test (IFAT) (95.5%, n = 178) and leptospirosis with a Microscopic Agglutination Test (MAT) (25.9%, n = 363). Significant associations were found between seroprevalence to some of the leptospiral serogroups detected (Tarassovi, Pomona, Sejroe and Mini) and age of the animals, animal density or location of the estates (being more prevalent in hotter and more humid areas). In addition, Mycobacterium bovis and M. avium subspecies paratuberculosis were confirmed in two deer carcasses by culture and PCR, respectively. No antibodies against Brucella spp. nor Rift Valley Fever virus were detected with the use of respective indirect ELISA's. The results obtained suggest that the population of rusa deer from Mauritius is exposed to a wide range of pathogens which may affect their productivity. In addition, the results highlight the potential public health risks incurred by deer industry workers and consumers. This survey fills an important gap in knowledge regarding the health of tropical deer meat in Mauritius and justifies the need to implement more regular surveys of selected pathogens in the deer population. (Resume d'auteur)

Background Few serological tests are available for detecting antibodies against Mycoplasma capricolum subsp. capripneumoniae, the causal agent of contagious caprine pleuropneumonia (CCPP). The complement fixation test, the test prescribed for international trade purposes, uses a crude antigen that cross-reacts with all the other mycoplasma species of the “mycoides cluster” frequently infecting goat herds. The lack of a more specific test has been a real obstacle to the evaluation of the prevalence and economic impact of CCPP worldwide. A new competitive ELISA kit for CCPP, based on a previous blocking ELISA, was formatted at CIRAD and used to evaluate the prevalence of CCPP in some regions of Kenya, Ethiopia, Mauritius, Tajikistan and Pakistan in an international collaborative study. Results The strict specificity of the test was confirmed in CCPP-free goat herds exposed to other mycoplasma species of the “mycoides cluster”. Prevalence studies were performed across the enzootic range of the disease in Africa and Asia. Seroprevalence was estimated at 14.6% in the Afar region of Ethiopia, whereas all the herds presented for CCPP vaccination in Kenya tested positive (individual seroprevalence varied from 6 to 90% within each herd). In Mauritius, where CCPP emerged in 2009, nine of 62 herds tested positive. In Central Asia, where the disease was confirmed only recently, no positive animals were detected in the Wakhan District of Afghanistan or across the border in neighboring areas of Tajikistan, whereas seroprevalence varied between 2.7% and 44.2% in the other districts investigated and in northern Pakistan. The test was also used to monitor seroconversion in vaccinated animals. Conclusions This newly formatted CCPP cELISA kit has retained the high specificity of the original kit. It can therefore be used to evaluate the prevalence of CCPP in countries or regions without vaccination programs. It could also be used to monitor the efficacy of vaccination campaigns as high-quality vaccines induce high rates of seroconversion.