Oliveira M C S, Oliveira-Sequeira T C G, Regitano L C A, Alencar M M, Néo T A, Silva A M, Oliveira H N
Southeast Embrapa, Rodovia Washington Luiz, km 234, Caixa Postal 339, CEP 13560-970, São Carlos, SP, Brazil.
Vet Parasitol. 2008 Aug 17;155(3-4):281-6. doi: 10.1016/j.vetpar.2008.04.022. Epub 2008 May 10.
Babesia bigemina infections were investigated in four genetic groups of beef cattle and in Rhipicephalus (Boophilus) microplus engorged female ticks. Blood samples and engorged female ticks were collected from 15 cows and 15 calves from each of the following genetic groups: Nelore, Angus x Nelore, Canchim x Nelore, and Simmental x Nelore. Microscopic examination of blood smears and tick hemolymph revealed that merozoites of B. bigemina (6/60) as well as kinetes of Babesia spp. (9/549) were only detected in samples (blood and ticks, respectively) originated from calves. PCR-based methods using primers for specific detection of B. bigemina revealed 100% infection in both calves and cows, regardless the genetic group. Tick infection was detected by nested-PCR amplifications showing that the frequency of B. bigemina was higher (P<0.01) in female ticks collected from calves (134/549) than in those collected from cows (52/553). The frequency of B. bigemina was similar in ticks collected from animals, either cows or calves, of the four genetic groups (P>0.05).
对四个肉牛遗传群体以及微小牛蜱饱血雌蜱中的双芽巴贝斯虫感染情况进行了调查。从以下每个遗传群体的15头母牛和15头小牛采集血样和饱血雌蜱：内洛尔牛、安格斯×内洛尔牛、坎辛×内洛尔牛和西门塔尔×内洛尔牛。对血涂片和蜱血淋巴进行显微镜检查发现，仅在源自小牛的样本（分别为血液和蜱）中检测到双芽巴贝斯虫裂殖子（6/60）以及巴贝斯虫属动合子（9/549）。使用针对双芽巴贝斯虫特异性检测的引物进行基于PCR的方法显示，无论遗传群体如何，小牛和母牛的感染率均为100%。通过巢式PCR扩增检测蜱感染情况，结果显示，从小牛采集的雌蜱（134/549）中双芽巴贝斯虫的感染频率高于从母牛采集的雌蜱（52/553）（P<0.01）。从四个遗传群体的动物（母牛或小牛）采集蜱中的双芽巴贝斯虫感染频率相似（P>0.05）。
