Detection of

摘要

This study aimed to elucidate the epidemiological status of hemoplasma infection and investigate the interaction between Theileria orientalisand hemoplasmas in Japanese Black breeding cows raised in the Kyushu and Okinawa regions. Blood samples were collected from 400 cows from 80 different farms ineight prefectures (five samples per farm and 10 farms per prefecture). Mycoplasma wenyonii (Mw), “Candidatus Mycoplasmahaemobos” (CMh), and T. orientalis were examined by polymerase chain reaction (PCR) assay using whole blood samples. PCR results showed that91.5% (366/400) of cows were positive for bovine hemoplasma: 40.3% were infected with Mw only, 9.5% with CMh only, and 41.8% with both species. T.orientalis was detected in 36% (144/400) of cows. The infection rate of T. orientalis was higher in the grazing group(P<0.001) than in the housed group, while the rate of CMh infection was higher (P<0.05) in the housed group than inthe grazing group, suggesting that not only the tick but also other arthropod vectors may contribute to hemoplasma transmission. Although the cows withhemoplasma dual infection showed higher (P<0.05) white blood cell counts compared with hemoplasma-negative cows, there was no difference inhematologic parameters related to the anemia between the hemoplasma-positive and -negative animals. This may indicate that Japanese Black cattle could haveresistance to the anemia caused by infection with hemoplasma.