“十三五”期间安徽省人群土源性线虫感染监测结果分析

Surveillance of human soil-transmitted nematode infection in Anhui Province during 2016—2020

目的了解2016—2020年安徽省人群土源性线虫感染情况,为制定土源性线虫病防治对策提供科学依据。方法2016—2020年安徽省按照《全国肝吸虫病和土源性线虫病监测方案(试行)》要求开展监测。每年选择一定数量的县(市、区)作为土源性线虫病监测点,监测点按地理方位划分为东、西、南、北、中等5个片区,每个片区抽取1个乡(镇、街道)的1个行政村(社区)开展监测工作,每个行政村(社区)整群抽取3周岁以上常住居民不少于200人。采集监测对象粪样(>30 g),采用改良加藤厚涂片法(一粪二检)检测土源性线虫(蛔虫、鞭虫、钩虫、蛲虫)感染情况,3~9周岁儿童加做透明胶纸肛拭法检测蛲虫感染情况,计算土源性线虫感染率和感染度等指标。采用卡方检验或趋势卡方检验进行感染率间的比较。结果2016—2020年安徽省分别设立土源性线虫病监测点6、16、14、14和21个,监测点人群土源性线虫感染率分别为2.14%(129/6032)、0.76%(125/16409)、1.26%(185/14704)、0.88%(132/14982)和0.58%(126/21575),总体呈逐年下降趋势,其中2020年比2016年下降了72.90%,不同年份间感染率差异有统计学意义(χ^(2)=143.68,P<0.05)。钩虫感染率相对较高,2016—2020年分别为1.94%(117/6032)、0.53%(87/16409)、1.07%(158/14704)、0.52%(78/14982)和0.43%(92/21575);蛔虫、鞭虫和蛲虫感染率始终保持在相对较低水平(0.01%~0.24%),呈散发状态。安徽省71个监测点中,土源性线虫感染率最高的为2016年的潜山市(11.02%,103/935),其次为2020年的固镇县(4.22%,43/1018);感染率大于1.00%的监测点有19个,占监测点总数的26.76%(19/71),主要分布于安徽北部地区。2016—2020年安徽省土源性线虫病监测点中,男性感染率分别为1.98%(62/3136)、0.67%(54/8009)、0.99%(70/7037)、0.95%(67/7052)和0.53%(56/10592),女性感染率分别为2.31%(67/2896)、0.85%(71/8400)、1.50%(115/7667)、0.82%(65/7930)和0.64%(70/10983),除2018年(χ^(2)=7.54,P<0.05)外,其余年份男性和女性感染率差异均无统计学意义(χ^(2)=0.82、1.57、0.73、1.10,均P>0.05)。5年监测中,感染率总体呈随年龄增长而升高、随文化程度增高而降低的趋势,其中不同年龄组中以≥71岁年龄组人群感染率最高,分别为1.73%(11/635)、1.19%(23/1926)、2.70%(51/1890)、1.68%(33/1970)、1.00%(29/2906);不同文化程度中以文盲和小学人群感染率最高,分别为3.08%(110/3567)、0.99%(111/11263)、1.63%(160/9794)、1.14%(117/10235)、0.61%(81/13345)。虫种构成中以钩虫占比最多,分别为90.70%(117/129)、69.60%(87/125)、85.41%(158/185)、59.09%(78/132)和73.02%(92/126)。土源性线虫感染度以轻度感染为主,中度感染和重度感染均较少见。结论“十三五”期间安徽省人群土源性线虫感染率总体呈逐年下降趋势,并处于低度流行状态;钩虫是主要感染虫种;皖北地区应是今后防治的重点地区。

Objective To understand the prevalence of soil-transmitted nematode(STN)infection in Anhui Province from 2016 to 2020 to provide scientific basis for formulating the STN control strategy.Methods The surveillance for STN was performed in Anhui Province according to the National Surveillance Program for Clonorchiasis and Soil-borne Nematodiasis(provisional version)during 2016—2020.A certain number of counties(cities,districts)were selected yearly as surveillance sites,each of which was further divided into 5 sectors according to its geographic location,i.e.,east,west,south,north,and central.From each sector,one township was randomly selected,and an administrative village was selected from the township to conduct surveillance.In the sampled village,no less than 200 permanent residents over 3 years old were cluster sampled.Fecal samples(>30 g)from the enrolled residents were collected and were examined for STN eggs using the modified Kato-Katz thick smear method(two slide-reading for each sample).Children aged 3-9 were additionally examined for Enterobius vermicularis eggs with the cellophane anal swab method.The infection rate and intensity of STN were calculated and descriptively analyzed.Chi-square test and Chi-square trend test were used to compare the infection rates.Results From 2016to 2020,6,16,14,14 and 21 surveillance sites were selected,the STN infection rate in the population in the 5years was 2.14%(129/6032),0.76%(125/16409),1.26%(185/14704),0.88%(132/14982)and 0.58%(126/21575),respectively.The infection rate showed an overall downward trend,with a decrease of 72.90%in 2020 compared to2016.The differences between the years were statistically significant(χ^(2)=143.68,P<0.05).The infection rate of hookworm was 1.94%(117/6032),0.53%(87/16409),1.07%(158/14704),0.52%(78/14982)and 0.43%(92/21575),respectively,while that of Ascaris lumbricoides,Trichuris trichiura and E.vermicularis was relatively low(0.01%-0.24%).Among the 71 surveillance sites in the province,the highest STN infection rate was found in Qianshan City(11.02%,103/935)in 2016,followed by Guzhen County(4.22%,43/1018)in 2020;and there were 19 surveillance sites with infection rate greater than 1.00%,mainly distributed in northern Anhui,accounting for 26.76%(19/71)of all the surveillance sites.From 2016 to 2020,the STN infection rate in males was 1.98%(62/3136),0.67%(54/8009),0.99%(70/7037),0.95%(67/7052),0.53%(56/10592)and in females was 2.31%(67/2896),0.85%(71/8400),1.50%(115/7667),0.82%(65/7930),0.64%(70/10983),respectively,there was no significant differences between genders(χ^(2)=0.82,1.57,0.73,1.10;P>0.05)except for 2018(χ^(2)=7.54,P<0.05).The STN infection rate showed an increasing trend with age and decreasing trend with education levels.The highest infection rate was found in the age group of"≥71"and the illiterate and primary school education group,which was 1.73%(11/635),1.19%(23/1926),2.70%(51/1890),1.68%(33/1970),1.00%(29/2906)and 3.08%(110/3567),0.99%(111/11263),1.63%(160/9794),1.14%(117/10235),0.61%(81/13345),respectively.For the STN specie compositions,the composition ratio of hookworm was the highest,which was 90.70%(117/129),69.60%(87/125),85.41%(158/185),59.09%(78/132)and 73.02%(92/126),respectively.For infection severety degrees,mild infection accounted for the majority,while moderate infection and severe infection were rare.Conclusion During the 13th Five-Year Plan period,the STN infection rate in Anhui Province showed a downward trend,being at a low prevalence status.Hookworm is the main infection species,and northern Anhui is the key area for STN control in the future.