Kiyohara Tomoko, Sato Tomoko, Totsuka Atsuko, Miyamura Tatsuo, Ito Toshihiro, Yoneyama Tetsuo
Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan.
Microbiol Immunol. 2007;51(2):185-91. doi: 10.1111/j.1348-0421.2007.tb03900.x.
Hepatitis A infection is caused by hepatitis A virus (HAV) contracted through fecal-oral transmission. Life-long immunity is conferred after infection. Improved sanitary conditions have generally resulted in a significant decline in the incidence of hepatitis A. However, a low incidence of infection results in increased HAV susceptibility. The present study investigates the prevalence of anti-HAV antibody and clarifies the current HAV status and HAV susceptibility in Japan at 2003.
A total of 2,430 serum specimens collected during 2003 from Japanese individuals ranging in age from 0-92 years, were tested for anti-HAV antibody using an inhibition enzyme linked immunosorbent assay. All specimens were obtained from the WHO and the National Serum Reference Bank/National Institute of Infectious Diseases, Tokyo, Japan.
The overall seroprevalence was 12.2%. Anti-HAV antibodies were rarely detected in individuals between 0-44 years of age. Starting from the age of 45-49 years, seropositivity gradually increased through age 65 years and above. Seroprevalence was not affected by gender, and geographic distribution did not affect age-specific seroprevalence until the age of 60 years.
HAV susceptibility in Japan is increasing annually. Particularly, the prevalence of anti-HAV antibody in individuals older than 50 years in 2003 was 50.3%, which is significantly lower than that of corresponding studies in 1994 (74.3%), 1984 (96.9%) and 1973 (96.9%). The growing susceptible population of advanced age results in more frequent HAV infection among them. The surveillance of anti-HAV antibody prevalence is useful for implementing preventive measures and for controlling the spread of HAV.
甲型肝炎感染是由通过粪-口传播途径感染的甲型肝炎病毒（HAV）引起的。感染后可获得终身免疫。卫生条件的改善总体上导致甲型肝炎发病率显著下降。然而，低感染率导致甲型肝炎病毒易感性增加。本研究调查了抗-HAV抗体的流行情况，并阐明了2003年日本当前的甲型肝炎病毒状况和甲型肝炎病毒易感性。
2003年期间从年龄在0至92岁的日本人中收集了总共2430份血清标本，使用抑制酶联免疫吸附测定法检测抗-HAV抗体。所有标本均来自世界卫生组织以及日本东京国立传染病研究所国家血清参考库。
总体血清阳性率为12.2%。在0至44岁的个体中很少检测到抗-HAV抗体。从45至49岁开始，血清阳性率随着年龄增长至65岁及以上逐渐升高。血清阳性率不受性别影响，并且在60岁之前地理分布不影响年龄特异性血清阳性率。
日本的甲型肝炎病毒易感性逐年增加。特别是，2003年50岁以上个体中抗-HAV抗体的流行率为50.3%，显著低于1994年（74.3%）、1984年（96.9%）和1973年（96.9%）的相应研究结果。老年易感人群的增加导致他们中甲型肝炎病毒感染更为频繁。对抗-HAV抗体流行率的监测有助于实施预防措施并控制甲型肝炎病毒的传播。
