近些年来，主要由蜱传播的人巴贝西虫感染疫情在世界多地不断蔓延，我国多个省市也陆续发现巴贝西虫感染确诊病例、亚临床特征病例、持续感染病例，严重威胁人民群众健康；并已成为输血安全的新威胁。但是，目前我国人巴贝西虫感染本底情况、遗传多样性及其分布、主要临床鉴别特征、感染来源及其风险、患者体内虫体持续感染动态变化以及自然疫源地的特征等研究非常匮乏。为此，本研究拟在我国蜱媒传染病复杂多样的东北林区、西南山区，近几年蜱虫疫情相对严重的河南与山东等地，依托哨点医院，开展较为系统的人巴贝西虫感染流行病学调查，并围绕病例周边的媒介蜱和宿主开展疫源地调查；同时，基于本研究组前期筛检的巴贝西虫患者和本项目新纳入患者建立队列，开展随访观察，研究巴贝西虫在人体内增殖变化规律及其与临床特征、体征及实验室检测指标和免疫相关指标的关联，为掌握我国巴贝西虫致病性特点及其健康威胁，提出更有针对性的防控措施提供科学依据。

In recent years, human babesiosis which are mainly transmitted by ticks have spread continuously in the US and Europe. The number of asymptomatic infection cases also were increasing. The confirmed clinical cases caused by different Babesia spp. have also been found in many provinces, China. Human babesiosis has been a serious and potential threat to human health, transfusion safety and even national biosecurity. However, little background information on human babesiosis and asymptomatic infection, including main clinical feature, genetic species or types and dominant strains, as well as the risk factors and characteristic of natural focus, is available in China. Therefore, we will select sentinel hospitals located at Heilongjiang province (northeast China), Henan province (central China) , Shandong (eastern China) and Yunnan (southwest China) where there exist many kinds of or relatively serious tick-borne diseases, and then investigate the prevalence and epidemiology of babesia in patients, tick vector and animal reservior. The expected results will be useful to elucidate the human babesiosis in China representative region,to provide important support and the basis for the diagnosis, treatment, prevention and control of huaman babesiosis in China.