THE EPIDEMIOLOGY OF HEPATITIS C INFECTION IN THAILAND

拟议的研究计划将涉及泰国北部丙型肝炎病毒（HCV）感染的流行病学、生物学和自然史的综合合作研究。丙型肝炎病毒感染是一个全球性的健康问题，是慢性肝病、肝癌和肝硬化的主要原因。据估计，美国有400万人，全世界有1.8亿人感染丙型肝炎病毒。在感染后，80%的人将成为慢性携带者，其中20%将在未来15-20年内发展为慢性肝病或癌症。在一些人群中的流行病学研究发现，注射吸毒者的丙型肝炎病毒感染率很高，性传播和围产期传播的感染率较低，但有所上升。然而，许多个体的感染是隐源性的。丙型肝炎病毒感染在如此高比例的感染者中持续存在的原因尚不清楚。然而，该病毒具有相当多的遗传多样性，随着新准种的出现而出现的病毒变异通常发生在慢性感染者身上。此外，丙型肝炎病毒的流行病学和传播与艾滋病毒交织在一起，因此许多感染了这两种病毒的人可能免疫抑制。我们计划进行的研究将涉及对泰国北部不同人群中丙型肝炎病毒感染的流行病学、病毒学和自然史的全面调查，其中大多数人正在接受艾滋病毒感染评估。肝癌是泰国癌症的主要原因之一，献血者中丙型肝炎病毒的患病率是美国的8-10倍。研究人群将包括注射吸毒者、性工作者、性病患者、新兵、献血者及其配偶和一般社区人群。通过将HCV研究技术转让给我们的合作者，我们希望将重点放在了解HCV的生物学和流行病学以及开发更有效的HCV预防上。

The proposed research program will involve integrated collaborative studies of the epidemiology, biology and natural history of hepatitis C virus (HCV) infections in Northern Thailand. Infections with HCV are a worldwide health problem and are a major cause of chronic liver disease, liver cancer and cirrhosis. It is estimated that 4 million persons in the United States and 180 million persons worldwide are infected with HCV. After infection 80 percent of individuals will become chronic carriers and 20 percent of them will progress to chronic liver disease or cancer in the next 15-20 years. Epidemiologic studies in some populations have found high rates of HCV in injection drug users and lower but elevated rates from sexual and perinatal transmission. However, infections in many individuals are cryptogenic. The reasons for the persistence of HCV infection in such a high proportion of infected individuals is not clear. However, the virus is genetically quite diverse and viral variation with the emergence of new quasispecies usually occurs in chronically infected people. Furthermore the epidemiology and transmission of HCV is intertwined with HIV, so many persons who are infected with both viruses may be immunosuppressed. The studies we have planned will involve comprehensive investigations of the epidemiology, virology and natural history of HCV infections in various populations in Northern Thailand, most of whom are being evaluated for HIV infection. Liver cancer is one of the leading causes of cancer in Thailand and HCV prevalence in blood donors is 8-10 fold greater than in the U.S. The study populations will include injection drug users, sex workers, STD patients, military recruits, blood donors and their spouses and general community populations. Through the transfer of technology for HCV research to our collaborators, we hope to focus on understanding the biology and epidemiology of HCV and the development of more effective prevention of HCV.