Seroprevalence of Trypanosoma vivax and other haemoparasites in bovines in French Guyana

An epidemiological survey was carded out in bovines, in French Guyana, with parasitological techniques, namely the WOO test and blood smear examinati- on, and 9 serological ELISA tests for antigen and/or antibody detection for several #Trypanosoma# sp., #Babesia# sp., #Anaplasma marginale# and #Theileria mutans# . The serological techniques fumished by ILRl are still under evaluation. Five breeding areas. were determined on the border cost of- the country. 2953 cattle were sampled between 91 and 92, and 4 herds, for a total of 200 heads were regularly sampled for the observation of seasonal variations. Amongst 509 observations of capillary tubes, 7.6% showed trypanosomes identified as Megabypanum species. Since #T. vivax# was not observed, it was concluded that the survey was conducted during a post- epizootic period. A marginale was observed in 28% of the 442 stained blood smears observed, and B, bigemina in 3 samples. The 2953 serum samples tested indicated that #Trypanosoma# sp. antibodies are present in 22% of the cattle, with 12% positives for antigens of #T. vivax#, 20% for #T. brucei# and 18%6 for #T. congolense#. The last two tests were considered as cross reacting with #T. vivax# since nether #T. evansi# nor #T. congolense# are present in French Guyana. There was no seasonal variations, but dairy cattle had higher prevalences than beef cattle, probably due to different management. Seroprevalence of #A. marginale# antigens was of 61%, in agreement with the epidemiological findings, since anaplasmosis is highly endemic in the country. Similarly, high semprevalences were found with #Babesia# sp. tests: 62% for #B. bovis", 22% antigens and 67% antibodies for #B. bigemina#. Antibody detection for meileda mutans were also performed, but were all negative, confidng the fact that this parasite is not present in the country. Re-evaluation of the antigen-ELISA for #Trypanosoma# sp, appeared necessary. (Résumé d'auteur)