南宁市福寿螺和褐云玛瑙螺感染广州管圆线虫调查分析

Investigation and analysis of Angiostrongylus cantonensis infection in Pomacea canaliculata and Achatina fulica in Nanning City

目的了解南宁市广州管圆线虫中间宿主福寿螺和褐云玛瑙螺的感染现状,为当地广州管圆线虫病的预防和控制提供依据。方法在居民生活区附近的公园、沟渠、水塘及生活区附近的农田和水库等处收集福寿螺和褐云玛瑙螺。采用酶消化法检查广州管圆线虫的感染情况,统计阳性率、幼虫数和幼虫中位数,并进行动物感染后对幼虫和成虫进行分子鉴定。结果从9个调查点共采集到250只福寿螺,其中有8个调查点发现有广州管圆线虫感染,感染率从2.86%到11.25%不等;单个螺检获幼虫数最多为7条,其余为1~3条,检获幼虫的中位数除一个调查点为1.5条外,其余点均为1条。从5个调查点共采集到90只褐云玛瑙螺,其中有3个点发现广州管圆线虫感染,感染率分别为6.25%、21.95%和80.00%,单个螺检获最多幼虫数分别为8、1 200和2 000条,幼虫中位数分别为8、70和100条。结论南宁市不同地区福寿螺普遍存在广州管圆线虫感染,但是感染率和虫体中位数较低。褐云玛瑙螺中的广州管圆线虫感染呈地域性分布,部分地区感染率和虫体中位数较高。南宁市福寿螺、褐云玛瑙螺感染广州管圆线虫情况广泛存在,居民有潜在的感染风险,应加强相应的防控工作。

Objective To understand the infection status of Angiostrongylus cantonensis in the intermediate host of Pomacea canaliculata and Achatina fulica in Nanning City, and provide evidence for the prevention and control of A.cantonensis in the local region. Methods P. canaliculata and A. fulica were collected in the parks, ditches, ponds and farmland and reservoirs near the residents' living area. The larvae of A. cantonensis were examined by enzyme digestion, the infection rate, the larvae number and median of larvae number were counted. The larvae were inoculated to infect the rats and the molecular identification of the young and adult worms collected from infected rats was conducted. Results Two hundred and fifty P. canaliculata were collected and examined from nine survey sites. Snails from eight survey sites carried the larvae of A. cantonensis, the infection rates of the snails were from2.86% to 11.25% in each site. The most number of larvae found in a single snail was 7, and the rest was 1~3. The median number of the larvae in each site was 1 except a survey site of 1.5. Ninety A. fulica were collected from five survey sites and the snails from three sites carried the larvae of A. cantonensis. The infection rates of the positive sites were 6.25%, 21.95% and 80.00%,respectively, and the most number of larvae found in the single snail was 8, 1 200 and 2 000, the median number of the larvae were 8, 70 and 100, respectively. Conclusion A. cantonensis is prevalent in P. canaliculata and A.fulica in different region of Nanning City. The infection rate and the median number of parasites in P. canaliculata are lower, while in A. fulica are high. The A. cantonensis is widespread in Nanning City, people could be infected and appropriate prevention measures should be taken.