Molecular Seroepidemiologic Studies on Piroplasmosis of Domestic Animals in Brazil

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(1) Serum samples from horses in the States of Sao Paulo and Mato Grosso do Sul, Brazil were examined for diagnosis of equine piroplasmosis by both the latex agglutination test (LAT) and the enzyme-linked immunosorbent assay (ELIZA) with recombinant antigens. Of the examined samples, 81% and 90% samples were positive for Babesia equi and Babesia caballi infection, respectively. Also, 75%75% samples were positive for both B. equi and B. caballi mixed infections. These results indicate that equine piroplasmosis is widespread and therefore a cause for serious concern in the States of Sao Paulo and Mato Grosso do Sul, Brazil.(2) The potential role of Boophilus microplus as natural tick vector of B. equi and B. caballi in Brazilian horses was assessed using nested polymerase chain reaction (PCR)-based marker assay. B. equi merozoite-specific 218bp gene fragment (EMA-1) was detected in 45.3-62.5% of females, eggs, larvae, and nymphs of B. microplus collected from 47 horses at the State of Ma … More to Grosso do Sul, Brazil.Except for the partially-fed female ticks, the B. caballi-specific 430 bp gene fragment was amplified from developmental stages. Therefore, we have obtained molecular evidence that strengthens earlier experimental and ultrastructural studies on Brazil incriminating B. microplus as a natural vector of B. equi, and possibly of B. caballi.(3) Primers specific for EMA-1 gene of B. equi successfully amplified products from all samples of Dermacentor nuttalli adult ticks from Mongolia while primers for the 430 bp gene fragment product from BC48 gene of B. caballi amplified products from seven of the 54 samples. We have found mixed infections with B. equi and B. caballi in the tick vector. These results suggest that D. nuttalli may play an important role as a vector of both B. caballi and B. equi and also may be important in maintenance of endemicity of equine piroplasmosis in Mongolia. The detection of parasite DNA in eggs and larval progenies is likewise suggestive of transovarial parasite transmission in D. nuttalli ticks.(4) At least three different variations in EMA-1 gene of B. equi strains isolated from different regions. The phylogenetic tree deduced from the sequences suggests a closer relationship between the Brazilian and Florida strains of B. equi DNA, and a distant relationship between B. equi DNA isolated from the Brazilian samples and USDA strain. B. equi gene obtained from Mongolian samples revealed comparatively distant relationship to other examined strains. Less