Molecular Seroepidemiologic Studies on Piroplasmosis of Domestic Animals in Brazil

(1)采用重组抗原乳胶凝集试验（LAT）和酶联免疫吸附试验（ELIZA）对巴西圣保罗州和南马托格罗索州的马血清进行检测，以诊断马螺形体病。马氏巴贝斯虫和卡巴贝斯虫感染阳性率分别为81%和90%。75%的样本对马布氏杆菌和caballi布氏杆菌混合感染均呈阳性。这些结果表明，马螺形体病广泛存在，因此在巴西圣保罗州和南马托格罗索州引起严重关注。(2)采用巢式聚合酶链反应（PCR）标记法，对巴西马中微量乳杆菌作为马布氏杆菌和卡巴利布氏杆菌天然蜱虫媒介的潜在作用进行了评价。在巴西南格罗索州（Grosso do Sul）马的47匹马的雌、卵、幼虫和若虫中，检测到45.3% ~ 62.5%的马B. equi merozoite特异218bp基因片段（EMA-1）。除部分摄食的雌蜱外，在发育阶段均扩增出caballi特异性430bp基因片段。因此，我们已经获得了分子证据，加强了早期的实验和超微结构研究，证明巴西微芽孢杆菌可能是马布氏杆菌的天然载体，也可能是caballi的天然载体。(3)马布氏EMA-1基因特异性引物成功扩增蒙古国所有肉芽革蜱成虫样本的产物，而卡巴氏BC48基因430 bp基因片段的引物成功扩增了54份样本中7份样本的产物。我们在蜱媒介中发现了马布氏杆菌和卡巴利杆菌的混合感染。这些结果提示，努塔利棘球绦虫可能是卡巴利布氏虫和马布氏虫的重要媒介，也可能在维持蒙古马螺旋体病的地方性中起重要作用。卵和幼虫子代中寄生虫DNA的检测同样提示了寄生虫在nuttalli蜱中的跨卵巢传播。(4)不同地区马布氏杆菌株的EMA-1基因存在至少3种不同的变异。从序列中推断出的系统发育树表明，巴西和佛罗里达的马B. DNA菌株之间的关系较近，而从巴西样本中分离的马B. DNA与美国农业部菌株之间的关系较远。从蒙古样品中获得的马双歧杆菌基因与其他检测菌株的关系相对较远。少

(1) Serum samples from horses in the States of Sao Paulo and Mato Grosso do Sul, Brazil were examined for diagnosis of equine piroplasmosis by both the latex agglutination test (LAT) and the enzyme-linked immunosorbent assay (ELIZA) with recombinant antigens. Of the examined samples, 81% and 90% samples were positive for Babesia equi and Babesia caballi infection, respectively. Also, 75%75% samples were positive for both B. equi and B. caballi mixed infections. These results indicate that equine piroplasmosis is widespread and therefore a cause for serious concern in the States of Sao Paulo and Mato Grosso do Sul, Brazil.(2) The potential role of Boophilus microplus as natural tick vector of B. equi and B. caballi in Brazilian horses was assessed using nested polymerase chain reaction (PCR)-based marker assay. B. equi merozoite-specific 218bp gene fragment (EMA-1) was detected in 45.3-62.5% of females, eggs, larvae, and nymphs of B. microplus collected from 47 horses at the State of Ma … More to Grosso do Sul, Brazil.Except for the partially-fed female ticks, the B. caballi-specific 430 bp gene fragment was amplified from developmental stages. Therefore, we have obtained molecular evidence that strengthens earlier experimental and ultrastructural studies on Brazil incriminating B. microplus as a natural vector of B. equi, and possibly of B. caballi.(3) Primers specific for EMA-1 gene of B. equi successfully amplified products from all samples of Dermacentor nuttalli adult ticks from Mongolia while primers for the 430 bp gene fragment product from BC48 gene of B. caballi amplified products from seven of the 54 samples. We have found mixed infections with B. equi and B. caballi in the tick vector. These results suggest that D. nuttalli may play an important role as a vector of both B. caballi and B. equi and also may be important in maintenance of endemicity of equine piroplasmosis in Mongolia. The detection of parasite DNA in eggs and larval progenies is likewise suggestive of transovarial parasite transmission in D. nuttalli ticks.(4) At least three different variations in EMA-1 gene of B. equi strains isolated from different regions. The phylogenetic tree deduced from the sequences suggests a closer relationship between the Brazilian and Florida strains of B. equi DNA, and a distant relationship between B. equi DNA isolated from the Brazilian samples and USDA strain. B. equi gene obtained from Mongolian samples revealed comparatively distant relationship to other examined strains. Less