一起由引进养殖黑山羊导致人感染羊痘病暴发的调查

目的 查明重庆市某村人群中暴发羊痘病的危险因素。方法采用统一的病例定义,在全村村民中搜索病例,病例采用统一调查问卷进行访谈,并采集疱疹液进行实验室检验。对全村引进养殖黑山羊的农户开展回顾性队列研究,分析与病羊接触方式、接触频度及接触时防护情况等与发病的关联性。结果共发现18名病例（疑似病例16例,确诊病例2例）,均来自引进养殖黑山羊的10户家庭。大腿夹羊者发病风险是未用大腿夹羊者的近5倍(RR-4.98,95％CI:1.34～75.27);洗羊者发病风险是未洗羊者的3倍（RR=3.09,95％CI:0.98～45.38）;接触病羊程度的评分值越高,发病风险性越大,呈剂量反应关系（趋势x2检验：P=0.006）;接触病羊时经常穿长衣裤是保护因素（RR=0.30,95％CI:0.15 ～ 0.78）。结论该村引进感染羊痘的黑山羊是导致本次人感染羊痘病暴发的原因。直接接触病羊和接触时未穿防护衣服是感染的危险因素。

An outbreak of human orf disease caused by introduced black goats

Objective To identify risk factors for a human orf disease outbreak in a village in Chongqing city. Methods Standardized case-definition was set and a case-finding program was conducted among all the residents of the village. All the patients were interviewed using a standardized questionnaire and collected fluids in the skin rash for laboratory testing. A retrospective cohort investigation was conducted among all the village residents who introduced the black goats to analyze the risk of orf infection, in relation to the mode and frequency of contacts to the infected goats. Results We found 18 cases (including 16 suspected cases and 2 confirmed cases) among the members of 10 families that introduced the black goats. Village residents who had ever used their legs to grip the goats were nearly five times as likely to develop orf disease as those who did not (RR=4.98, 95％CI: 1.34-75.27). Village residents who had ever washed and wiped the goats were three times as likely to develop orf disease as those who had not (RR = 3.09,95％CI: 0.98-45.38). The frequency of contacts with the infected goats was associated with the risk of developing orf disease in a dose-response fashion (x2 test for trends: P= 0.006).Frequently wearing long trousers when dealing with the goats appeared as a protective factor (RR=0.30,95％CI: 0.15-0.78). Conclusion This outbreak was caused by the introduced black goats which carried and infected by the orf virus. Direct physical contact with infected goats but without wearing protective clothing were risk factors for the development of human orf disease.