关键词: 人体重点寄生虫病, 流行现状, 调查

Abstract: 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 Enterobius 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 of 617 441 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 was 5.96%, 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 Enterobius 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.

Key words: Human parasitic diseases, Current situation, Survey