Abstract:

Objective To understand the endemic status and epidemiological trend of schistosomiasis within national surveillance sites in Jiangxi Province so as to provide a scientific basis for the better prevention and control of schistosomiasis in the whole province. Methods According to the National Schistosomiasis Surveillance Program (2014 edition), total 39 national schistosomiasis surveillance sites were set up in 39 endemic counties (cities, districts) in Jiangxi Province to surveil the transmission and infection of schistosomiasis in local population, livestock and snails, and to investigate the factors related to the transmission during October to November, 2015-2018. Indirect hemagglutination assay (IHA) was used to detect antibody against Schistosoma in local residents and mobile population with age over 6 years old within these surveillance sites. Modified Kato-Katz and egg concentrated/hatch method were used to examine the eggs in the feces of people and livestock in triplicate. Infection of snails was determined by tissue dissection under microscope and LAMP was used to detect parasite DNA. Results Total 45 086 residents and 31 272 mobile population in the selected schistosomiasis surveillance sites in Jiangxi Province were involved in the survey during 2015-2018, with average 4.61% (2 080/45 086) serological positive for residents and 1.78% (556/31 272) positive for mobile population. The range of serological positive for local residents in different year was 4.01%-5.58%, and for mobile population was 1.24%-2.36%, all with highest in 2017, with statistical difference among different years (P < 0.01). The serological positive rate for local resident male 5.41% (1251/23 124) and mobile male 2.15% (394/18 322), which were significantly higher than female residents of 3.77% (829/21 962) and mobile population of 1.25% (162/12 950) (P < 0.01). People > 55-year-old had positive serological rates of 6.22% (902/14 504) for local residents and 2.37% (152/6 421) for mobile population, which were higher than those of other age groups (P < 0.01). The serological positive rate in farmers and fishers was 6.06% (1 932/31 868) for residents and 3.09% (383/12 408) for mobile, which were significantly higher than those of other occupational groups of 1.12% (148/13 218) and 0.92% (173/18 864), respectively (P < 0.01). Only 6 fecal egg positive cases was found in the local residents with 3 male and 3 female, 5 of them with age over 55 years old. All of them were farmers and fishers living around Poyang Lake. No case was found in mobile population. Total 4 128 livestock were monitored during 2015-2018 and no cattle was found egg positive in their fecal samples. A total of 10 510.11 hm² area were examined for snail, 2 907.58 hm² of them contained snails. The density of live snails was 0.16 to 0.66/(0.11 m²). 23 007 live snails were tested by LAMP, and 935 tubes of mixed samples were detected, 4 of them were positive and all from East Turtle Island, Xinhua Village, Lushan City in 2015. Conclusion At present, the risk area of schistosomiasis transmission in Jiangxi province is mainly located around Poyang Lake. Males with age over 55 engaged in agriculture and fishing work are the main risk population for Schistosoma infection. Risk of schistosomiasis transmission still remains in Jiangxi Province. In the future, the schistosomiasis monitoring system should be further strengthened and the high-risk populations in the lake area should be regularly monitored in order to achieve the goal to block the transmission of schstosomiasis in the province in near future.

Key words: Schistosomiasis, National surveillance sites, Endemic situation, Jiangxi Province