福建政和县原并殖吸虫疫区疫情变化及其原因分析

Changes and root cause analysis of Paragonimus in primary endemic areas in Zhenghe county

目的比较政和县并殖吸虫疫区的第一、二中间宿主感染率今昔变化,并分析其原因。方法收集政和县原有4个疫区的螺、蟹,分别检查其携带的并殖吸虫尾蚴和囊蚴,将其结果同原感染率、感染度做比较。结果 4个疫区中的3个并殖吸虫尾蚴和囊蚴感染率、感染度均比10~20年前有明显的下降,原因为疫区被城市化的建筑扩展、新近建立的养鸭场、果林种植和农药、化肥的残留物的影响;1个疫区变化不大,系与前后调查间隔仅6年,环境和条件无变化相关。结论政和县4个中的3个并殖吸虫疫区10~20年来因人为因素的影响,其第一、第二中间宿主的感染率有明显下降。

Objective To compare the infection rate o f the first and the second intermediate hosts o f Para- gonimus in primary endemic areas in history and present days in Zhenhe county, and analyze the causes affecting the changes. Methods Intermediate hosts, including snails and crabs were collected in the four primary endemic areas within Zhenghe county, and detected for the present status of live cercariae and metacercariae. Then the infection rate and infectiosity were compared with those in history records. Results Infection rate and infectiosity for the cer-cariae and metacercariae of Paragonimus were significantly reduced in 3 of the 4 primary endemic areas as compared with the data maintained 10 ~20 years ago. The causes for the decrease were associated with urbanization, newly es-tablished duckery, residues of pesticides and chemical fertilizers applied to the fruit planting. Another one endemic area remained no obvious change, because of no significant modification of environment and living conditions as a result of the shorter intervals（6 years） with the previous survey. Conclusion The infection rate for the first and the second intermediate hosts of Paragonimus are significandy reduced in the 3 of the 4 historical endemic areas within Zhenghe county in the past decade to 20 years, and the decrease is associated with human factors.