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In the present study, a total of 137 blood samples were collected from cattle and water buffaloes in central region of Vietnam and tested using nested polymerase chain reaction (nPCR), enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFAT) to determine the molecular and serological prevalence of Babesia bovis and Babesia bigemina. In cattle, the prevalence of B. bovis and B. bigemina was 21.3% and 16.0% by nPCR, 73.4% and 42.6% by ELISA and 60.6% and 59.6% by IFAT, respectively, whereas those of water buffalos were 23.3% and 0% by nPCR, 37.2% and 9.3% by ELISA and 27.9% and 18.6% by IFAT, respectively. IFAT and ELISA detected a higher number of infected cattle and water buffaloes than nPCR totally. Statistically significant differences in the prevalence of the two infections were observed on the basis of age. Overall, the current data suggest high incidence of B. bovis and B. bigemina infections in the central region of Vietnam, which is needed to develop comprehensive approach to the modern surveillance, diagnosis and control of bovine babesiosis.

Hemoprotozoan infections often cause serious production losses in livestock. In the present study, we conducted a PCR-based survey of Babesia bovis, Babesia bigemina, Theileria annulata, Theileria orientalis, Trypanosoma evansi and Trypanosoma theileri, using 423 DNA samples extracted from blood samples of cattle (n=202), water buffaloes (n=43), sheep (n=51) and goats (n=127) bred in the Hue and Hanoi provinces of Vietnam. With the exception of T. annulata and T. evansi, all other parasite species (B. bovis, B. bigemina, T. orientalis and T. theileri) were detected in the cattle populations with B. bovis being the most common among them. Additionally, four water buffaloes and a single goat were infected with B. bovis and B. bigemina, respectively. The Hue province had more hemoprotozoan-positive animals than those from the Hanoi region. In the phylogenetic analyses, B. bovis-MSA-2b, B. bigemina-AMA-1 and T. theileri-CATL gene sequences were dispersed across four, one and three different clades in the respective phylograms. This is the first study in which the presence of Babesia, Theileria and Trypanosoma parasites was simultaneously investigated by PCR in Vietnam. The findings suggest that hemoprotozoan parasites, some of which are genetically diverse, continue to be a threat to the livestock industry in this country.

Babesia ovata is a tick-transmitted hemoprotozoan parasite that infects cattle. In our study, bovine blood samples (n=2,034) were collected from 10 different countries (Brazil, China, Ghana, Japan, Mongolia, the Philippines, South Africa, Sri Lanka, Thailand and Vietnam) and DNA extracted. The DNA samples were screened using an established and specific polymerase chain reaction (PCR) assay targeting the Apical membrane antigen 1 (AMA-1) gene. Parasite DNA was detected among samples collected from Japan, Mongolia and Thailand. Sequence analyses confirmed that the PCR assay detected only B. ovata AMA-1, and that amplicons from different geographical locations were conserved. Our findings highlight the importance of designing adequate strategies to control B. ovata infection in Japan, Mongolia, and Thailand.