广东省部分地区淡水养殖环境卫生及华支睾吸虫中间宿主感染情况分析

目的了解广东省部分地区淡水养殖的环境卫生及华支睾吸虫中间宿主感染情况，为制订有效的华支睾吸虫病控制对策提供参考。方法2008--2009年分别在佛山市顺德区、江门市新会区、中山市、龙川县等4个县（市、区），采用分层多级抽样方法各抽取50～100个鱼塘样本调查环境卫生情况。在上述鱼塘样本中，分层随机抽取5～15个样本检测华支睾吸虫中间宿主，每个鱼塘抽检淡水鱼、螺各10～50条（只）。采用面对面访谈相关人员及实地观察方式调查塘上或塘边粪便直接入塘的厕所或动物栏及使用人或动物粪便喂养淡水鱼等卫生情况，采用直接压片法检查螺体内华支睾吸虫尾蚴，消化法检查鱼体内华支睾吸虫囊蚴。结果4个县（市、区）共抽取250个鱼塘进行环境卫生调查，存在塘上或塘边粪便直接入塘的厕所或动物栏及使用人或动物粪便喂养淡水鱼等4种情况中任1种情况的鱼塘百分率，以新会区为最高，达86．57％（58／67），其余依次为顺德区（35．56％，16／45）、中山市（34．69％，34／98）、龙川县（27．50％，11／40）（P〈0．01）。在四地抽检35个鱼塘的淡水鱼和淡水螺，采获11种淡水鱼488条。4个县（市、区）的淡水鱼囊蚴阳性率在14．70％－56．25％之间，顺德区最高，达56．25％（45／80）；鲩鱼、鲢鱼、鳙鱼、鲮鱼、白鲫、梭边鱼及石娟鱼7种淡水鱼检出华支睾吸虫囊蚴阳性。受检样本量超过5条的阳性鱼种中，以鲩鱼阳性率为最高，达47．31％（79／167），其次为鲢鱼（45．45％，20／44）。仅在顺德区采集到135只淡水螺样本，纹沼螺及长角涵螺检出华支睾吸虫阳性，平均尾蚴阳性率为3．70％（5／135）。不同卫生情况鱼塘淡水鱼囊蚴阳性率的比较显示，带有粪便入塘厕所的鱼塘淡水鱼总阳性率（35．15％，58／165）、鲩鱼（主要的淡水鱼生鱼种）阳性率（62．07％，36／58）均不同程度高于其他卫生情况（P〈0．01）。结论广东省部分地区均存在不同程度的人或动物粪便污染鱼塘水体及淡水鱼、螺的华支睾吸虫感染情况，应把鱼塘直接排污厕所的清除或改建等粪便管理工作列为控制工作的重点，才能更有效地阻断华支睾吸虫病的传播。

Current status of environmental sanitation and clonorchis sinensis intermediate host infection of freshwater aquaculture in partial areas of Guangdong Province

Objective To understand the current status of environmental sanitation and clonorchis sinensis infection of freshwater aquaculture in some areas of Guangdong Province. Methods About 50 - 100 fish pond samples were planned to collect for the environmental sanitation survey by stratified multi - stage sampling in Shunde District of Foshan City, Xinhui District of Jiangmen City, Zhongshan City and Longchuan County during 2008--2009. From the fish pond samples described above, 5 - 15 samples were selected by stratified random sampling for the examination of clonorchis sinensis intermediate hosts, 10 -50 pieces of fish and snails, respectively, were planned to examine in each pond. The sanitation situations,including the toilets or animal sheds with the stool drained into fish ponds directly and freshwater fish feeding with human or animal stool, etc., were surveyed by face to face interviews and on-site observation. clonorchis sinensis cercaria in snails was examined by direct compression method and the metacercaria in fish examined by digestion method. Results Totally 250 fish pond samples were collected for the environmental sanitation survey. The fish pond percentage with any of the 4 situations including the toilets or animal sheds with the stool drained into fish ponds directly and freshwater fish feeding with human or animal stool was 86. 57% （58/67）, highest in Xinhui District,and followed by 35.56% （16/45） in Shunde District, 34. 69% （34/98） in Zhongshan City and 27.50% （11/40） in Longchuan County （ P 〈 0.01 ）. A total of 488 pieces of freshwater fish in 11 species were detected from selected 35 ponds in the 4 regions. The metacercaria positive rates of freshwater fish in 4 counties （ cities/districts ） were from 14. 70% to 56. 25% , and 7 species of grass carp, silver carp, bighead, dace, crucian carp, Suo Bian fish and Shi Juan fish were examined for clonorchis sinensis metacercaria positive. Among the positive fish species with sample size over 5, the positive rate of grass carp was highest, up to 47. 31% （79/167）, and followed by silver carp （45.45% , 20/44）. 135 freshwater snail samples were acquired only in Shunde District, and parafossarulus striatulu and alocinma Iongicornis were detected clonorchis sinensis positive, with a mean cercaria positive rate of 3.70% （5/135）. The comparisons of the metacercaria positive rates of freshwater fish in fish ponds with different sanitation situations showed that both the total positive rate of freshwater fish in fish ponds with the stool-drained-into-pond toilet （35.15% , 58/165） and the positive rate of grass carp in the ponds （62. 07% , 36/58） were higher in various degrees than those with other sanitation situations（P 〈0. 01 ）. Conclusion The situations that human or animals＇stool polluted fish pond water and freshwater fish and snails were infected by clonorchis sinensis in various degrees existed in the 4 surveyed counties （cities/districts） of Guangdong Province. The stool management, including the elimination or reconstruction of the toilets discharging dirt directly in aquaculture places, should be the focus of control work, to block the spread of clonorchiasis more effectively.