云南省玉溪市红塔区鼠型斑疹伤寒病原及血清流行病学调查

Epidemiologic investigation on murine typhus in Hongta areas of Yuxi city, Yunnan province of China

目的明确玉溪市红塔区是否为鼠型斑疹伤寒疫源地。方法采用微量室温补体结合法，对红塔区人群和鼠类进行鼠型斑疹伤寒（莫氏）立克次体血清抗体检测，用鼠、鼠体外寄生节肢动物标本接种豚鼠进行病原体分离，并调查鼠密度和鼠蚤指数。结果调查的7镇14个调查点人群血清抗体均检出阳性，总阳性率28．92％（96／332），几何平均滴度（GMT）为10．83，其中发热患者和健康人群抗体阳性率分别为31．86％（72／226）和22．64％（24／106）；男女阳性率分别为26．71％（43／161）、30．99％（53／171），性别间差异无统计学意义（P〉0，05）；年龄组阳性率分别为0-6岁29．63％（8／27）、7-18岁18．06％（13／72）、19-39岁39．62％（42／106）、40-59岁27．50％（22／80）、60岁以上23．40％（11／47），各年龄组差异有统计学意义（P〈0．05）；10个调查点捕获的鼠类均检出抗体，阳性率为44．95％（89／198），GMT为30．30；从11组鼠类标本中分离到5株莫氏立克次体，从6组蚤类标本中分离到3株莫氏立克次体，病原体分离率为44．44％（8／18），其中鼠类为45．45％（5／11）、蚤类为50．00％（3／6）；1组螨类标本接种豚鼠未引起豚鼠发病；确诊1例鼠型斑疹伤寒病例；褐家鼠和黄胸鼠占捕鼠总数的99．49％（197／198）、印鼠客蚤占捡蚤总数的74．26％（303／408），鼠蚤指数为2．06，鼠密度为11．13％。结论红塔区人群和鼠类中存在鼠型斑疹伤寒，且处在较高感染水平，可认定该区为鼠型斑疹伤寒疫源地。

Objective To identify epidemic status of murine typhus in Hongta areas of Yuxi city and to provide evidence for control and prevention of the disease. Methods Serologic survey was conducted among residents and rodents. Isolation of Rickettsia moseri was performed. Results The overall infection rate among general population was 28.92 % （96/332） with geometric meantiter（GMT） as 10.83 and there wasno difference between males and females （26.71%, 43/161 vs. 30.99%, 53/171, P〉0.05）. Significant differences were found between age groups （ P 〈 0.05） with positive rates of 29.63 % （8/27）, 18.06% （13/72）, 39.62% （42/106）, 27.50% （22/80）and 23.40% （11/47）among age groups 0-6, 7-18, 19-39, 40-59 and over 60, respectively. The overall rate of infection in mouse was 44.95% （89/198） with GMT as 30.30. Five isolates of R. moseri from mouse specimen, three from fleas plus one ease of murine typhus were diagnosed. Rattus norvegicus and Rattus flavipectus were the predominant species of rodent animals （99.49%, 197/198） and Xenopsylla cheopis was the major species of vector （74.26%, 303/408）. Flea index and mouse density were 2.06 and 11.13 % respectively. Conelusi0n High infection rates on R. moseri were demonstrated in rodents and residents as well as high risk of routine typhus outbreak might occur in these areas.