1998年水灾后受灾地区甲型肝炎血清流行病学调查

Seroepidemiology of Hepatitis A in Folld Stricken Areas in 1998 in China

为了解水灾后甲型肝炎（甲肝）的流行动态，在湖北和内蒙古等7个受灾省（自治区，下同）中，于1999年1～4月采集1～25岁正常人群血清14322人份。用酶联免疫吸附试验（ELISA）检测了甲肝抗-HAVIgG，部分抗-HAVIgG阳性血清过一步检查抗-HAVIgM。结果表明，灾区人群甲肝抗体平均阳性率（51.27％）明显高于非灾区（42.21％），首次证明甲肝流行与受灾有联系．甲肝抗体阳性率随年龄增长而升高．除湖北（72.7％）和江西（88.4％）两省外。其亡省的灾区和非灾区1～25岁人群甲肝抗体阳性率均＜50％，属甲肝抗体低屏障区．在松花江流域甲肝抗体水平明显低于1992年的调查结果．首次用检测抗-HAVIgM的方法，在正常人群中证明有散在的甲肝亚临床病例存在（1.1％），7个省无一例外，是隐蔽的传染源。

In order to investigate the seroepidemiology in hea1thy people after 1998 's floodin China, we made a survey in seven flood-stricken provinces (Jiangsu, Jiangxi, Anhui,Hubei, Jiling, Heilongiiang and Nei mingol). In each province, one flooded county and onenon-flooded county were selected. By the method of random stratified cluster sampling,7 347 healthy people of 1- 25 years old were se1ected from seven flooded counties and 6 957people of the same age from seven non- flooded counties. A total of 14 322 serum samplescollected from Jan-April,1999 were tested by ELISA for anti-HAV IgG and a part ofthese positive samples were further tested for anti -HAV IgM. The results showed: ① Theaverage anti-HAV IgG positive rate of 1-25 years old healthy people in seven floodedcounties were 51 .27%, signigicantly higher than that in seven non - flooded counties. Thismay indicate an association of HA prevalence with the flood; ② The HAV antibody posi-tive rate in Jiangxi Province was 88.74% in flooded counties and 72.21 % in non - floodcounties while that in Hubei Province was 72.70% and 73.01 % respectively. In other fiveprovinces, the HAV antibody positive rate were all <50%, ③ The HAV antibody positiverate increased along with the age, they were 31 .8%, 22.8% in 1 - 4 years old healthy peo-respectively, ④ When comparing HAVantibody level in < l5 year old people, threeprovinces (Jilin, Heilongiiang, Nei mongial)locating in the Songhuajiang Valley andNengiiang Valley showed a much more lowerlevel in 1999 than that in 1992, while the otherfour provinces (Jiangsu, Anhui, Jiangxi, Hubei)locating in Changriang Valley had no differences, @ 3OO serum samples randomly collectedfrom HAV-IgG positive samples of flooded and non -flooded counties of each provincewere all tested for HAV- IgM, the positive rate was 1 .1 %(23/2 095) indicating the subclinicalHAV infection scattering in seven provinces, they were the hidden source for HA transmission.