2004年宁海县肺吸虫中间宿主流行病学调查报告

Epidemiological Investigation on Intermediate Hosts of Paragonimus in Ninghai County in 2004

目的调查宁海县深圳区肺吸虫中间宿主溪蟹和川蜷螺的分布、感染情况，观察其生态习性，从而估计当地人群肺吸虫感染的危险度。方法现场捕捉溪蟹和川蜷螺，同时观察其生态环境及活动习性。将蟹称重、捣碎、研磨、水洗过筛后，取沉渣镜检。将川蜷螺用针挑出软体，压片、镜检。结果共捕获溪蟹97只，从单只捣碎检查溪蟹（体重高于5g）中，查获9只阳性蟹，感染率11．7％。肺吸虫囊蚴的感染率与溪蟹本身大小存在差异，蟹重15—25g组感染率最高，达20．0％（4／20），而5—15g组感染率为10．2％（5／49），25—35g组蟹中未检出囊蚴。雄蟹感染率（12．7％）稍高于雌蟹（9．1％）。检查20只小蟹（体重〈5g），以5只为一组，共查获2组阳性蟹。共采集川蜷螺200只，未发现阳性螺。肺吸虫中间宿主栖息在清澈、氧气充足的溪水中，水流缓慢或相对静止的水体比较适合它们的生存。结论当地人群中仍存在肺吸虫感染的危险因素，政府及卫生机构仍应积极防治肺吸虫病。

Objective To investigate the infections and distribution of intermediate hosts of paragonimus including crabs and snails, to observe their habits and to estimate the risk of people＇s infection with paragonimus. Methods Crabs and snails were collected from the spots. Their ecological environment and behavior were observed. The crabs were weighed and treated with regular precipitation method and the precipitates were examined under microscopy. Results Total number of crabs was 97. Out of crabs weighed over 5g, there were nine positive crabs with the infective rate of 11.7%. The infective rate was associated with the weight of crabs. Crabs weighing between 15g and 25g had the highest rate to 20.0%, but no snails were found in crabs weighing between 25g and 35g. 20 small crabs （weighing lower than 5g} were divided into four groups and two positive groups were found. No cercariae were found in 200 snails. The intermediate hosts of paragonimus lived in clear streams with rich oxygen. Streams with slow water flows or relative immobile were more suitable for their survival. They ofen breed in the middle and upper segment of rivers. Conclusions Local people are still in danger of infection with paragonimus, so the government and the department of sanitation should keep on making tively. effort and taking measures to prevent people from paragonimus infection and treat paragonimiass actively.