广州市2002年登革热爆发疫情流行病学特征分析

The Epidemic Situation Analysis on the Outbreak of Dengue Fever in Guangzhou in 2002

目的分析广州市2002年登革热疫情流行病学特征,为今后登革热预防控制提供依据。方法在全市建立和完善登革热疫情报告、监测和媒介监测网络;访视报告的每个病例或可疑病例,并在疫点周围展开病例搜索;采集登革热病例、疑似病例、疫点部分人群血作血清学或病原学检测;对非疫点、疫点蚊媒进行调查。结果广州市2002年共报告登革热病例1423例,发病率为20.14/10万,无死亡病例。疫情以城市居民区为主,随后向城郊、农村扩散,最后涉及全市12个区、县级市,共102个行政街(镇)。以街(镇)为单位计算,最高的发病率达212.4/10万。流行季节为5月中旬～11月下旬,高峰为7～9月;3～12月份全市平均布雷图指数为5.0～19.8;病毒为登革Ⅰ型;潜伏期为2～8d;爆发疫点人群隐性感染率达17%;各年龄组人群均易感,但低年龄组发病率略低。结论2002年广州市发生登革热大流行,其持续时间、波及范围为广州市历史之最,总体流行态势处于半自然状态。早期病例未及时诊断,疫情发现迟,疫情控制不力是疫情扩散的主要原因。广州市存在有利登革热流行的自然、社会因素;近3年连续流行同一型别病毒,登革热是否有本地化趋势应密切关注。

Objective To analysis the epidemic characters of the outbreak of dengue fever in Guangzhou in 2002 and provide the scientific bases for the prevention and control measures. Methods The networks for the surveillance and reporting dengue fever was established in Guangzhou. The serum samples were collected from the reported cases, suspected cases and ordinary population at epidemic spot for the detection of anti dengue virus antibodies and dengue virus. The mosquito vector at epidemic spot and non epidemic spot were investigated as well. Results There was 1423 reported cases of dengue fever in Guangzhou in 2002. The incidence rate was 2.01 per ten thousand and the mortality rate was zero. The epidemic situation involved 12 districts and city counties. Using street or twon as base, the incidence rate was 21.2 per ten thousand. The epidemic season was from mid of May to the third week of November. The peak epidemic season was from July to September. The BI of the whole city was from 5 to 20. The dengue virus isolated was belong to type I. The average incubation period was from 2 to 8 days. The rate of hidden infection of population nearby the epidemic spot was 17%. The whole population was suceptable to dengue virus infection, but the incidence rate of young age group was lower than other age groups. Conclusions The epidemic trend of the outbreak of dengue fever in Guangzhou in 2002 was semi natural. The epidemic period was the longest and the affected area was the widest of the record. The epidemic situation in Guangzhou was related to the local natural environment and social factors. The virus causing the outbreak in the past 3 years was typeⅠdengue virus. We should aware of the trend of localization of dengue virus in Guangzhou.