Detection of Babesia bovis and Babesia bigemina in Water Buffaloes (Bubalus bubalis) in Endemic Areas of S?o Paulo State, Brazil

摘要

Babesiosis is a tick-transmitted disease that causes severe economic losses to the cattle industry in Brazil. Water buffaloes (Bubalus bubalis) are often carriers of Babesia spp., but there are no studies that provide an accurate estimation of this infection in animals raised in regions of endemic stability. This study was conducted to investigate Babesia bovis and B. bigemina infections in 108 water buffaloes (50 calves and 58 adult females) located in areas of São Paulo state, where the animals were continuously exposed to Rhipicephalus microplus ticks. B. bovis and B. bigemina infections were screened by microscopic examination of blood smears, nested PCR (nPCR) and quantitative real-time PCR (qPCR), which were also used to estimate the number of copies (NC) of the cytochrome b (mt-cytB) gene in the blood samples. B. bigemina was found in blood smears of three calves from Alambari herd (all with less than 0.1% parasitemia). Molecular techniques were more sensitive than blood smears to diagnose piroplasms in water buffaloes: 20.37% and 100.00% for B. bovis-infected animals and 59.26% and 100.00% for B. bigemina-infected animals, respectively for nPCR and qPCR. The NC of mt-cytB gene of B. bovis and B. bigemina in blood samples revealed significant effects (p p ≤ 0.05) for B. bigemina (2.80 ± 0.06) than for B. bovis (2.61 ± 0.05). Within each herd-age, differences between the species’ NC values were found only in Alambari calves, which showed significantly higher (p ≤ 0.05) NC of B. bigemina (3.48 ± 0.13). The calves and cows from Ibaté showed the lowest NC of B. bigemina (2.29 ± 0.13 and 2.63 ± 0.14) and B. bovis (2.54 ± 0.11 and 2.37 ± 0.12), respectively. These data suggest a high prevalence of B. bovis and B. bigemina infection in the buffalo population in endemic areas of São Paulo state.