猪蛔虫对人群蛔虫感染和传播作用的实验流行病学研究

目的：了解在人蛔虫和猪蛔虫感染并存的农村社区内因交叉感染发生的可能性，猪蛔虫对人群蛔虫感染传播的作用。方法：选择两个基线情况基本相同的自然村，即江西省新建县樵舍乡蔓湖行政村的老支村和畔支村为实验现场。在对两村所有人群进行相同药物治疗处理的同时，对其中1个村的猪群也进行治疗，并以约2个月的间隔重复对猪治疗2次，但对另一村的猪群不作治疗处理。在随后1年内，约每2个月1次，用改良加藤法观察两村人群蛔虫感染的回升情况。结果：药物治疗后连续5次横断面调查表明，人群蛔虫流行率和感染度在两村之间均无统计学差异（X^2＜0.658，F＜1.658，P＞0.1）。结论：当地猪蛔虫的传播对人群蛔虫的传播无重要影响。

Epidemiological study on the influence of pig -derived Ascaris to the transmission of human ascariasis

OBJECTIVE: An experimental epidemiological study was designed to investigate possible relations of pig-derived Ascaris to the transmission of human ascariasis which might be caused by cross-infection between the pig and humans. METHODS: In Xinjian County, Jiangxi province, two adjacent villages, Laozhi and Panzhi, with similar baseline of ascariasis in pig and human populations were selected as the study sites with a one-year longitudinal epidemiological follow-up study. People in the two villages received mass chemotherapy. Pigs received mass chemotherapy only in Panzhi village and was twice repeated with two months interval, while pigs in Laozhi village were not treated at all. In the following year after treatment on humans, ascariasis among villagers was studied cross-sectionally five times with Kato-katz technique. RESULTS: No significant difference of the re-infection patterns of human ascariasis was found between the two villages in terms of prevalence and intensity during the following year in all the five surveys (chi(2) < 0.658, F < 1.658 and P > 0.1). CONCLUSION: The results suggested that pig-derived Ascaris were mainly transmitted among pigs but had no important role on the transmission of human ascariasis. The results were in good accordance with the findings through a recent molecular genetic research on the local human-and pig-derived Ascaris worms. Possible confounding factors were discussed.