2015年全国人体重点寄生虫病现状调查分析

目的了解和分析全国人体重点寄生虫病的流行现状和态势,为制定防治规划提供科学依据。方法 2014-2016年在全国31个省(直辖市、自治区,未包括港澳台地区)的农村地区根据全国生态功能区划分和各县农民年人均纯收入划分(高、中、低),采用分层整群随机抽样的方法,在每省抽取4~36个县,每县抽取2~4个自然村,共1 890个调查点,每个调查点抽样调查常住居民250人,采集粪便,应用改良加藤厚涂片法(Kato-Katz法,一粪二检)检测蠕虫感染情况,生理盐水涂片法和碘液涂片法检测原虫感染情况,对3~6岁儿童采用透明胶纸肛拭法检测蛲虫感染情况。同时,在城镇地区调查人群华支睾吸虫感染情况,按感染水平将全国划分为5类华支睾吸虫流行区(Ⅰ-Ⅴ),不同流行区类型的各省抽取2~37个县,在城镇地区以居委会为调查点,共抽样517个调查点,每个调查点调查常驻居民250人,仅调查华支睾吸虫感染情况。结果全国31个省(直辖市、自治区)共调查617 441人,其中农村484 210人,城镇133 231人,检出重点寄生虫感染者20 351例,检出率为3.30%;查出虫种34种,其中蠕虫23种,原虫11种。重点寄生虫加权感染率为5.96%,推算感染人数约为3 859万。其中蠕虫加权感染率为5.10%,肠道原虫加权感染率为0.99%,推算感染人数约为642万;土源性线虫加权感染率为4.49%,推算感染人数约为2 912万;3~6岁儿童蛲虫感染率为3.43%,推算感染人数约为155万;带绦虫加权感染率为0.06%,推算感染人数约为37万。全国华支睾吸虫加权感染率为0.47%,推算感染人数约为598万;农村华支睾吸虫加权感染率为0.23%,推算感染人数约为152万;城镇华支睾吸虫加权感染率为0.71%,推算感染人数约为446万。重点寄生虫感染流行呈明显区域性分布,土源性线虫中、高度流行区主要分布在四川、海南、贵州、云南、重庆、广西、广东和江西等省(直辖市、自治区)。华支睾吸虫流行区主要集中在广东、广西、黑龙江和吉林等省(自治区);带绦虫感染仍然主要分布在西藏;3~6岁儿童蛲虫高感染地区主要集中在海南、江西、广东、广西、贵州和重庆等省(直辖市、自治区)。50%以上的肠道原虫感染者集中分布在西藏、贵州和广西等西部省(自治区)。结论全国重点寄生虫感染率大幅降低,尤其是土源性线虫病下降最明显,绝大部地区处于低度流行或散发状态,且流行区域也明显缩小,但仍有一些省或局部地区感染较严重。重点寄生虫感染流行呈明显区域性分布,土源性线虫中、高度流行区主要分布在西南和南部两大片区,华支睾吸虫流行区主要分布在华南和东北两大片区,带绦虫仍然主要分布在西藏,3~6岁儿童蛲虫高感染地区主要集中在华南和西南地区,肠道原虫呈现出局部地区感染率较高的特点,主要分布在西部省份。我国农村地区重点寄生虫感染人数仍然较多,防控任务仍然艰巨。

National survey on the current status of important human parasitic diseases in China in 2015

Objective To understand and analyze the current status and endemic trends of important human parasitic diseases,and provide scientific basis for the formulation of control programs in China.Methods The survey was carried out in 31 provinces(autonomous regions/municipalities)(hereinafter referred to as "P/A/Ms",excluding Hong Kong,Macao and Taiwan regions) of China from 2014 to 2016,using stratified cluster random sampling method.In rural areas,survey sites were selected based on the strata of ecological function in the nationwide eco-mapping and farmer’s income level(high,moderate and low annual net income per capita) in the county,by sampling 4-36 counties per province and 2-4 natural villages each sampled county.Totally,1 890 survey sites were sampled,from each of them 250 permanent residents were surveyed by fecal examination for helminthes infection using modified Kato-Katz thick smear method(one sample,two slide-readings),applying saline smear and iodine solution smear method for protozoa infection,and by anal transparent tape test to examine Enter obius vermicularis infection for the children aged 3-6 years.In urban areas,however,only human Clonorchis sinensis infection was surveyed by fecal examination.For this purpose,the country was categorized into five endemic regions(I-V) based on the C.sinensis infection prevalence by region.A total of 517 survey sites were sampled,by selecting 2-37 counties from each province of all endemic regions,and taking urban resident community as the survey site.From each site,250 permanent residents were surveyed for C.sinensis infection.Results A total of617 441 people were surveyed in 31 P/A/Ms,comprising 484 210 from rural areas and 133 231 from urban areas,among them,20 351 were found infected with important parasites(detection rate,3.30%).A total of 34 species of parasites were found,including 23 helminth species and 11 protozoan species.The weighted infection rate of important parasites was5.96%,accordingly,having estimated 38.59 million infected people.More specifically,the weighted infection rate of helminths was 5.10%,and that of intestinal protozoa was 0.99%,estimating 6.42 million people being infected.The weighted infection rate of soil-transmitted helminthes(STHs) was 4.49%,estimating 29.12 million people infected.The infection rate of Euterobius vermicularis was 3.43% in children aged 3-6 years,estimating 1.55 million infected children.The weighted infection rate of Taenia spp.was 0.06%,estimating 0.37 million infected.The weighted infection rate of C.sinensis in the country was 0.47%,estimating 5.98 million infected people.The weighted infection rate of C.sinensis in rural areas and urban areas was 0.23% and 0.71%,respectively,estimating 1.52 million and 4.46 million people infected.The important parasite infection displays an obvious regional distribution.The highly endemic areas of STHs infection were mainly distributed in Sichuan,Hainan,Guizhou,Yunnan,Chongqing,Guangxi,Guangdong and Jiangxi;the endemic areas of C.sinensis were restrictedly distributed in Guangdong,Guangxi,Heilongjiang and Jilin;the Taenia infection was mainly distributed in Tibet;and the highly endemic areas of E.vermicularis infection in children aged 3-6 years were mainly located in Hainan,Jiangxi,Guangdong,Guangxi,Guizhou and Chongqing.Over 50% of intestinal protozoa-infected people were distributed concentratedly in west China including Tibet,Guizhou and Guangxi.Conclusion The infection rate of important parasites,especially STHs,has been reduced significantly in China,showing a low level of prevalence or sporadically distributed in most of areas,and the scope of endemic regions has been markedly reduced as well.However,severe infection still exists in some provinces or local areas.The important parasite infection displays evident regional distribution pattern.Medium-and high-prevalence areas of STHs are mainly distributed in two broad regions in south and southwest China.The endemic areas of C.sinensis infection are mainly distributed in another two broad regions in southern and northeastern part of China.Taenia infection remains distributed in Tibet.The highly endemic areas of E.vermicularis infection in children aged 3-6 years are concentrated located in the southern and southwestern China.The intestinal protozoa infection is characterized with higher infection occurred in some limited areas,mainly distributed in western provinces.The number of people infected with important parasites in rural areas remains high,thus,prevention and control in this regard is still an arduous task.