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Title: Prevalence of equine Piroplasmosis and its association with tick infestation in the State of Sao Paulo, Brazil

item KERBER, C - Universidad De Sao Paulo
item LABRUNA, M - Universidad De Sao Paulo
item FERREIRA, F - Universidad De Sao Paulo
item DE WAAL, D - University College - Ireland
item Knowles Jr, Donald
item GENNARI, S - Universidad De Sao Paulo

Submitted to: Brazilian Journal of Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2009
Publication Date: 10/1/2009
Citation: Kerber, C.E., Labruna, M.B., Ferreira, F., De Waal, D.T., Knowles Jr, D.P., Gennari, S.M. 2009. Prevalence of equine Piroplasmosis and its association with tick infestation in the State of Sao Paulo, Brazil. Brazilian Journal of Veterinary Parasitology. 18(4):1-8.

Interpretive Summary: The recent finding of horses infected with Babesia (Theileria) equi within the United States has increased the need to understand the transmission risks associated with this long-term infection of horse red blood cells. This study used assays which detect antibody to the two parasites which cause babesiosis in horses, Babesia (Theileria) equi and Babesia caballi. Use of these assays in the State of Sao Paulo in Brazil defined the percentage of horses infected with either of these parasites. Also the study identified certain ticks which were associated with infection and these data help direct studies in the United States at defining which ticks are capable of transmitting one or both of the above listed parasites.

Technical Abstract: Serum samples were collected from 582 horses from 40 stud farms in the State of São Paulo and tick (Acari: Ixodidae) infestations were evaluated on them. Serum samples were subjected to the complement fixation test (CFT) and a competitive inhibition ELISA (cELISA) for Babesia caballi and Theileria equi. Logistic regression analyses were performed to construct multivariate models that could explain the dependent variable (horses positive for B. caballi or T. equi) as a function of the independent variables (presence or abundance of each one of the tick species found on the farms). A higher overall prevalence of B. caballi (54.1%) than of T. equi (21.6%) was found by the two tests. The ticks Dermacentor nitens Neumann, 1897, Amblyomma cajennense (Fabricius, 1787) and Rhipicephalus (Boophilus) microplus (Canestrini, 1887) were present on horses on 38 (95%), 20 (50%), and 4 (10%) farms, respectively. Infestations by D. nitens were statistically associated with B. caballi-positive horses on the farms by either the CFT or cELISA. Infestations by A. cajennense were statistically associated with T. equi-positive horses on the farms by either CFT or cELISA.