Serological and molecular prevalence of equine piroplasmosis in Western Java, Indonesia

Equine piroplasmosis is an economically significant disease caused by Theileria equi and Babesia caballi, which are tick-borne hemoprotozoan parasites. Infections with these parasite species had never been reported in horses in Indonesia. The aim of the present study was to investigate the prevalence of T. equi and B. caballi in horses reared in parts of Western Java, Indonesia. Blood samples were collected randomly from 235 horses in four different districts (Bandung, Depok, Tangerang, and Bogor) in Western Java, Indonesia. Thin blood smears prepared from the sampled animals were stained by Giemsa and observed under a light microscope. Serum samples prepared from blood were screened by enzyme-linked immunosorbent assays (ELISAs) based on recombinant forms of EMA-2 and BC48 antigens to determine the seroprevalence of T. equi and B. caballi, respectively. DNA samples extracted from the same blood samples were screened by EMA-2 and BC48 gene-based nested polymerase chain reaction (nPCR) assays for T. equi and B. caballi infections, respectively. Of 235 surveyed animals, five (2.1%) and 15 (6.4%) were seropositive for T. equi and B. caballi, respectively, whereas one and four horses were nPCR-positive for T. equi and B. caballi, respectively. All of the surveyed animals were negative for T. equi and B. caballi by microscopy. The T. equi EMA-2 and B. caballi BC48 gene fragments amplified by the nPCR assays were cloned, sequenced, and subjected to bioinformatic and phylogenetic analyses. The T. equi EMA-2 gene sequence from an Indonesian horse was identical to sequences from Florida and Washington strains and clustered together with these sequences in phylogeny. On the other hand, four Indonesian BC48 gene sequences shared 99.8-100% identity scores. This present study is the first to report T. equi and B. caballi in horses in Indonesia. Our findings highlight the need for monitoring horses in Indonesia for clinical piroplasmosis caused by T. equi and B. caballi.