Molecular epidemiology of relapsing fever and prevention of Borrelia infection

对坦桑尼亚中部一个村庄的种群进行了疏螺旋体调查。通过血液玻片检测螺旋体，对媒介蜱和人血液样本进行巢式聚合酶链式反应。在检测感染方面，聚合酶链式反应的敏感性提高了一倍，显示了疏螺旋体。在发烧的儿童中有11.1%，在其他健康儿童中有4.2%。疏螺旋体的基因分型从18例感染中发现了杜通氏疏螺旋体和一种新的未命名物种，人类或其他脊椎动物都不知道。该疏螺旋体的系统发育分析与新大陆复发性热疏螺相似。该病毒以前是从侵扰房屋的牛壁虱中分离出来的，它是坦桑尼亚中部由壁虱传播的回归热的一种新的病原体。坦桑尼亚多多马附近的Mvumi使命村的房屋中也收集到了扁虱。以鞭毛蛋白基因为基础的套式聚合酶链式反应检测所有硬蜱是否感染疏螺旋体。所有的房子都有大量的壁虱，所有收集到的壁虱都是虎斑鸟。在120只硬蜱中有51只感染了螺旋体，鞭毛基因序列比较显示，大多数螺旋体属于杜通疏螺旋体，它是东非硬蜱传播复发热的病原体。其余的螺旋体与杜通氏杆菌有很大的不同。这表明新疏螺旋体是分布的，是该地区复发热的病原体。利用16S核糖体RNA基因序列进行的系统发育分析也支持该螺旋体是一个有别于先前描述的该属成员的疏螺旋体。

The population of a central Tanzanian village were investigated for Borrelia sp. spirochaetes by blood slide examination, nested PCR for vector ticks and human blood samples. PCR was twice as sensitive in detecting infections, revealing Borrelia sp. in 11.1% of children with fever, and 4.2% of otherwise healthy children. Genotyping Borrelia sp. from 18 infections identified Borrelia duttonji and a new unnamed species, not known from humans or other vertebrates. Phylogenetic analysis of this Borrelia was resembled New World relapsing fever borreliae. Previously isolated from Ornithodoros porcinus ticks infesting houses, this is a new causative agent of tick-borne relapsing fever in Central Tanzania. Ticks were also collected from the houses in Mvumi Mission village, near Dodoma, Tanzania. All ticks were examined for Borrelia infestation by flagellin gene-based nested polymerase chain reaction. All houses were highly infested with ticks, and all ticks collected were of the Ornithodoros porcinus species. Fifty-one out of 120 ticks were infected with spirochetes, and a flagellin gene sequence comparison showed that most of the spirochetes belonged to Borrelia duttonii, which is the causative agent of tick-borne relapsing fever in East Africa. The rest of the spirochetes were quite different from B. duttonii. This indicates the new Borrelia is distributed and is causative agent of relapsing fever in the area. Phylogenetic analysis using 16S ribosomal RNA gene sequences also supported that the spirochete was a Borrelia species distinct from previously described members of the genus.