上海市闵行区1998—2007年麻疹流行病学特征分析与控制策略探讨

Study on epidemiological characteristics and control strategy of measles in Minhang district of Shanghai from 1998 to 2007

目的分析上海市闵行区1998—2007年麻疹流行病学特征变化规律，探讨麻疹控制策略，为加速控制麻疹提供科学依据。方法根据上海市常规传染病报告系统和人口学资料，对1998—2007年麻疹疫情资料进行描述流行病学分析。从疑似患者的咽拭子样本分离病毒，分析其基因特性及抗原性。结果麻疹年平均发病率为17．69／10万，主要是20岁以上成人和小于8月龄幼儿；发病季节高峰在3-5月，户籍人口麻疹流行无明显周期性，非户籍人口2～3年一个流行高峰。健康人群不同年龄组抗体水平差异有统计学意义（χ^2=86．06，P〈0．01），抗体水平在20—30岁最低。从10例疑似患者咽拭子样本中分离到4株麻疹病毒株，与麻疹疫苗株S191分属于不同的基因型，抗原性有一定的差异。结论麻疹流行特征已发生根本性改变，流行周期不明显，发病年龄呈双向移位，不典型症状增多。非户籍人口的发病特征更接近于自然感染，对全市麻疹流行病学特征产生了重要的影响。麻疹病毒株与疫苗株存在差异，因此监测地方性流行株的基因和抗原变化很有必要。现阶段应在对儿童保持高水平麻疹疫苗接种率的前提下，对特定人群开展麻疹疫苗强化免疫，采取针对性免疫策略和加强麻疹监测工作是减少麻疹发病的主要策略。

Objective To study the epidemiological characteristics and control strategy of measles in Minhang district of Shanghai from 1998 to 2007, and to provide scientific methods for measles controlling. Method Descriptive epidemiology study was conducted to analyse on the epidemiology of measles epidemics from the regular report system of infectious diseases and annual statistics of measles from 1998 to 2007. Collect laryngopharyngeal swabs from 10 suspect patients to separate measles virus, analyze its genotype and antigen variation. Rusults The incidence rate was 17.69/10^5 annually. The peak age of measles was adults above 20 years age and children below 8 months. And there was a seasonal peak between March and May. There was no periodical change in native population. However, it still existed in floating population with epidemiological peak of 2 to 3 years each. Antibody monitored results showed that it was the lowest at ages between 20 and 30 in healthy population which was accorded with the peak age. There was a statistical difference between ages （χ^2= 86.06, P 〈 0.01）. From 10 suspect measles patients, 4 measles strains were separated, the genotypes were different from vaccine strains. Conclusions The epidemiological characteristics of measles has been changed substantially, that is, the epidemic period is disappeared, and the age of onset is changed, the symptom is non-typical. The characteristics of measles in floating population in Minhang is more like natural infection that it exert an important influence on the epidemiological characteristics of measles in Shanghai. Monitoring variation in genes and antigens for endemic field strains become necessary. A high level of regular immunization should be maintained, while it should be strengthened to the specific groups. Specific immune strategy and measles monitoring should be taken to decrease the incidence rate of measles.