三峡库区蓄水后重庆段钩端螺旋体病流行动态监测

目的分析三峡库区重庆段二期蓄水前后钩端螺旋体病（钩体病）的流行病学特征变化,了解钩体菌型谱和优势菌型,防止钩体病疫源地向三峡库区和长江下游地区扩散。方法选择长寿区和丰都县为监测点,开展钩体病传染源监测,用显微镜凝集试验（MAT）检测患者、健康人群及耕牛血清抗体。结果三峡库区蓄水前后均有散发钩体病例。2001-2005年总蓄水前和蓄水后鼠密度的差异无统计学意义（X^2=1．00,P＞0．05）。蓄水前优势鼠种为褐家鼠,蓄水后为鼩鼱。鼠带菌率为1．72%（10/583）,与PCR检测阳性率（16．51%）差异有统计学意义（X^2=51．80,P＜0．01）。患者血清钩体抗体阳性率为73．33%（33/45）,血清群以澳洲群为主。健康人群钩体抗体阳性率为26．84% （233/868）,流行前期阳性率（23．85%）与流行后期（29．86%）比较,差异有统计学意义（X^2=3．99,P＜0．05）。牛血清钩体抗体GMRT为1：29．97,优势菌群为拜伦群。结论三峡库区二期蓄水后未出现钩体病流行,蓄水前后鼠密度无明显变化,但优势鼠种发生了变化,主要流行菌群为澳洲群,人群自然感染免疫水平较低,是钩体病潜在的流行地区。

Surveillance on the dynamics of leptospirosis epidemics in the Chongqing Section of the Three Gorges dam area

OBJECTIVE: To analyze the changes of leptospirosis epidemic characteristics before and after the Phase 2 'reservoir store water project' in Chongqing section of the Three Gorges dam area and to provide prevention, control and intervention measures to prevent the spread of leptospirosis from infectious focus to the Three Gorges dam area and downstream region of Changjiang River. METHODS: Changshou district and Fengdu county were selected as surveillance sites. We monitored the source of infection through examining the serum antibody of patients, healthy groups together with farm cattle measured by micro agglutination test (MAT). RESULT: Sporadic cases were reported before and after the storage of water in the reservoir. There was no significant difference found between mouse density before and after the Phase 2 reservoir project (chi2 = 1.00, P > 0.05). The main species of rat were Sewer rat before and Insectivorea after the storage of water. The germ-carrying rate of rats was 1.72% (10/583) and positive carrying rate of rats was 16.51% (18/109) when using PCR. Results showed a significant difference when comparing it to culture method (chi2 = 51.80, P < 0.01). Positive rate of leoptopirosis appeared in the serum of patients was 73.33% (33/45) with the major serum group as the Australia group. The rate of infection among the healthy group was 26.84% (233/868). There was significant difference seen between the serum antibody positive rate of epidemic prophase (23.85%) and epidemic anaphase (29.86%) of the healthy group (chi2 = 3.99, P < 0.05). The GMRT of ox serum antibody of leoptopirosis was 29.97 with Bailen group as the predominant microbial population. CONCLUSION: There was no epidemics of leptopirosis occurred in the Three Gorges dam area. There was no significant difference between mouse density before and after the storage of water in the reservoir. However, the major species of rats had a change. The natural infection level of people living in the dam area was low, but there existed potential of leoptopirosis outbreak.