Nagano Daisuke, Sivakumar Thillaiampalam, De De Macedo Alane Caine Costa, Inpankaew Tawin, Alhassan Andy, Igarashi Ikuo, Yokoyama Naoaki
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
J Vet Med Sci. 2013 Nov;75(11):1463-70. doi: 10.1292/jvms.13-0251. Epub 2013 Jul 12.
In the present study, we screened blood DNA samples obtained from cattle bred in Brazil (n=164) and Ghana (n=80) for Babesia bovis using a diagnostic PCR assay and found prevalences of 14.6% and 46.3%, respectively. Subsequently, the genetic diversity of B. bovis in Thailand, Brazil and Ghana was analyzed, based on the DNA sequence of merozoite surface antigen-1 (MSA-1). In Thailand, MSA-1 sequences were relatively conserved and found in a single clade of the phylogram, while Brazilian MSA-1 sequences showed high genetic diversity and were dispersed across three different clades. In contrast, the sequences from Ghanaian samples were detected in two different clades, one of which contained only a single Ghanaian sequence. The identities among the MSA-1 sequences from Thailand, Brazil and Ghana were 99.0-100%, 57.5-99.4% and 60.3-100%, respectively, while the similarities among the deduced MSA-1 amino acid sequences within the respective countries were 98.4-100%, 59.4-99.7% and 58.7-100%, respectively. These observations suggested that the genetic diversity of B. bovis based on MSA-1 sequences was higher in Brazil and Ghana than in Thailand. The current data highlight the importance of conducting extensive studies on the genetic diversity of B. bovis before designing immune control strategies in each surveyed country.
在本研究中，我们使用诊断性聚合酶链反应（PCR）检测法对从巴西（n = 164）和加纳（n = 80）饲养的牛身上获取的血液DNA样本进行了牛巴贝斯虫筛查，发现其流行率分别为14.6%和46.3%。随后，基于裂殖子表面抗原-1（MSA-1）的DNA序列，分析了泰国、巴西和加纳牛巴贝斯虫的遗传多样性。在泰国，MSA-1序列相对保守，且在系统发育树的单个分支中被发现，而巴西的MSA-1序列显示出高度的遗传多样性，并分散在三个不同的分支中。相比之下，加纳样本的序列在两个不同的分支中被检测到，其中一个分支仅包含一个加纳序列。泰国、巴西和加纳的MSA-1序列之间的同一性分别为99.0 - 100%、57.5 - 99.4%和60.3 - 100%，而各国推导的MSA-1氨基酸序列之间的相似性分别为98.4 - 100%、59.4 - 99.7%和58.7 - 100%。这些观察结果表明，基于MSA-1序列，巴西和加纳的牛巴贝斯虫遗传多样性高于泰国。目前的数据突出了在每个被调查国家设计免疫控制策略之前，对牛巴贝斯虫遗传多样性进行广泛研究的重要性。
