Comparison of US and European Babesia divergens Isolates

描述（由申请人提供）：巴贝斯虫是一种蜱传播的血液原虫寄生虫，在欧洲引起人类巴贝斯虫病。分化巴贝斯虫及其媒介蜱虫都不是美国本土的。然而，最近在肯塔基州的一个居民中发生的急性巴贝斯虫病病例被证明是由一种在形态上与欧洲分化巴贝斯虫难以区分的寄生虫引起的。在肯塔基州病例中发现的寄生虫在小亚基核糖体RNA基因序列上仅与欧洲的发散贝氏杆菌有3个碱基位置的差异，提供了同源性的证据。最近，据报道，从南塔开特岛的棉尾兔中分离出的巴贝斯虫与肯塔基州寄生虫的基因序列相同。分子流行病学也在楠塔基特岛的蜱虫中发现了这种寄生虫，这表明存在地方性动物疾病。

DESCRIPTION (provided by the applicant): Babesia divergens is a tick transmitted hemoprotozoan parasite that causes human Babesiosis in Europe. Neither B. divergens nor its vector tick are indigenous to the U.S. However, a recent case of acute Babesiosis in a resident of Kentucky was shown to be caused by a parasite morphologically indistinguishable from European Babesia divergens. The parasite in the Kentucky case was found to differ in the small subunit ribosomal RNA gene sequence at only 3 base positions from that of European B. divergens, providing evidence of conspecifity. Recently a Babesia isolate from cottontail rabbits on Nantucket Island was reported to have an identical gene sequence to that of the Kentucky parasite. Molecular epidemiology has also identified this parasite in Ixodes ticks on Nantucket Island, suggesting that an enzootic situation exists. The identification of another Babesia sp. in the US capable of causing human babesiosis is of major concern. Two other Babesia species that cause human Babesiosis in the US, Babesia microti, occurring mostly in the northeastern U.S., and the WA1 isolate, occurring in Washington state and California, have been implicated in blood transfusion acquired cases of babesiosis. Thus, the finding that another previously unknown human blood pathogen is troublesome. The purpose of this study is to compare the culture requirements and target genes of the Kentucky and Nantucket Babesia isolates with European B. divergens (Purnell strain) to determine if conspecificity exists among these parasites. Specific aims include establishing in vitro cultures of the Nantucket isolate and molecular comparison of ITS, HSP70, and cysteine protease genes from European B. divergens with those of the Kentucky and Nantucket isolates. Cultures of the Nantucket isolate will provide an unlimited source of parasites to complete these goals and for future studies. The molecular aspects may provide information that will be useful in future efforts to devise diagnostic tests.