自从1996年有了可以预防甲型肝炎的疫苗以来，美国加利福尼亚州正发生最大规模的甲型肝炎人与人之间的传染。
迄今加州已发现了600多个病例，其中21人死亡。加州公共卫生部说，大部分感染甲型肝炎的人是无家可归者和在卫生状况不佳的地方使用毒品的人。
洛杉矶市区有一个流浪人口聚集的地区。最近一项调查显示，那里的卫生状况低于联合国的难民营标准。根据联合国标准，每20人应有一个公共厕所。
分析人士说，糟糕的卫生状况成为甲型肝炎病毒流行的温床。
The U.S. state of California is experiencing the largest person-to-person outbreak of Hepatitis A in the United States since a vaccine to prevent the liver disease became available in 1996.
More than 600 cases have been reported in the state and 21 people have died. According to the California Department of Public Health, most of those infected are homeless or use drugs in places where sanitation has been a challenge.
An area in downtown Los Angeles is known for its homeless population. A recent study found that the area fell short of U.N. refugee camp standards calling for one public toilet for every 20 people.
Analysts say unsanitary conditions can become a breeding ground for the hepatitis A virus.