Pohl Anna Elisabeth, Cabezas-Cruz Alejandro, Ribeiro Múcio Flávio Barbosa, Silveira Júlia Angélica Gonçalves da, Silaghi Cornelia, Pfister Kurt, Passos Lygia Maria Friche
Rev Bras Parasitol Vet. 2013 Jan-Mar;22(1):129-35. doi: 10.1590/s1984-29612013000100024.
Bovine anaplasmosis, caused by the tick-borne rickettsia Anaplasma marginale, is endemic in tropical and subtropical regions of the world and results in economic losses in the cattle industry. Major surface proteins (MSPs) have been used as markers for the genetic characterization of A. marginale strains and demonstrate that many isolates may occur in a given geographic area. However, in Brazil, little is known about the genetic diversity of A. marginale isolates within individual herds. This study was designed to examine the genetic variation among A. marginale infecting calves in a farm in the south of Minas Gerais State, Brazil. Blood samples collected from 100 calves were used to prepare Giemsastained smears that were microscopically examined for the presence of A. marginale. From each blood sample, DNA was extracted and analyzed by a polymerase chain reaction (PCR), followed by sequencing to determine diversity among the isolates. Examination of blood smears showed that 48% of the calves were infected with A. marginale, while the real-time PCR detected 70.2% positivity. Congenital infections were found in four calves. The microsatellite and tandem repeat analyses showed high genetic diversity among the isolates.
牛无形体病由蜱传播的立克次氏体边缘无形体引起，在世界热带和亚热带地区流行，给养牛业造成经济损失。主要表面蛋白（MSPs）已被用作边缘无形体菌株遗传特征的标记，并表明在特定地理区域可能存在许多分离株。然而，在巴西，关于单个牛群中边缘无形体分离株的遗传多样性知之甚少。本研究旨在检测巴西米纳斯吉拉斯州南部一个农场中感染边缘无形体的犊牛之间的遗传变异。从100头犊牛采集的血样用于制备吉姆萨染色涂片，显微镜检查是否存在边缘无形体。从每个血样中提取DNA，通过聚合酶链反应（PCR）进行分析，然后测序以确定分离株之间的多样性。血涂片检查显示，48%的犊牛感染了边缘无形体，而实时PCR检测到阳性率为70.2%。在4头犊牛中发现了先天性感染。微卫星和串联重复分析显示分离株之间存在高度遗传多样性。
