Abstract:

Objective To identify the risk factors of scrub typhus and provide the basis for prevention and control of this disease. Methods A case-control study was conducted to identify the risk factors of the scrub typhus epidemic in the city. All clinically diagnosed cases and confirmed cases were included as the case group. For each patient, two controls were randomly selected from the symptom-free villagers with the same sex and an age gap of smaller than 5 years in the same village. The data were inputted into EpiData 3.1 and analyzed using conditional logistic regression model in SPSS 17.0. Results A total of 78 scrub typhus cases were found, including 16 laboratory-confirmed cases, 34 clinically diagnosed cases and 28 suspected cases. The 1∶M multiple conditional logistic regression analysis showed that sowing and harvest was the risk factor of this epidemic (OR＝6.33, 95%CI:1.12-37.25). Further analysis showed that 51.6% patients and 22.8% of the control subjects had took part in the harvest of soybeans, a risk factor of scrub typhus (OR＝3.62, 95%CI:1.36-9.59). However, the relationship between this epidemic and corn harvest and wheat sowing was not evident (P>0.05). Conclusion The event was an epidemic of scrub typhus among farmers due to bites of mite larvae during unprotected harvest of soybeans.

Key words: Scruby typhus, Case-control study, Risk factors, Epidemic

摘要：

目的 探讨造成此次恙虫病流行的危险因素，为疫情控制提供科学依据。方法 利用病例对照研究，探索造成此次恙虫病流行的危险因素。以搜索到的临床诊断病例和确诊病例作为病例组，按1∶2个体匹配的方式，随机选择与病例所在行政村的同村、年龄相差5岁以内的同性别且无任何临床症状的村民为对照。统计分析方法用1∶M的条件logistic回归，数据录入用EpiData 3.1软件，用SPSS 17.0软件进行数据的统计分析。结果 此次调查共发现恙虫病病例78例，其中实验室确诊病例16例，临床诊断病例34例，疑似病例28例。1∶M的多因素条件logistic回归分析结果表明，收种庄稼是造成此次恙虫病流行的危险因素(Or=6.33，95%CI：1.12～37.25)。进一步分析得知，51.6%的病例和22.8%的对照人群参加了收黄豆，是恙虫病发病的危险因素(Or=3.62，95%CI：1.36～9.59)，尚不能认为收玉米和种麦与本次恙虫病流行有关(P>0.05)。结论 此次事件是由于农民收黄豆时未采取保护措施而被恙螨幼虫叮咬引起的恙虫病流行。

关键词: 恙虫病, 病例对照研究, 危险因素, 流行