Epidemic trend of scrub typhus in the world.

Scrub typhus,infection with Orientia tsutsugamushi due to the bite by larvae of chigger mites,is an ancient vector-borne disease in Southeast Asia. During the World War Ⅱ,the disease occurred frequently in army in Southeast Asia and caused a lot of casualties,arousing great concern. After World War Ⅱ,reported scrub typhus cases gradually decreased, however,since 1980s,the incidence of scrub typhus has showed an upward trend,and the geographical distribution has also expanded. Currently,the incidence of scrub typhus is high in most traditional endemic counties in East Asia,South Asia, Southeast Asia and North Oceania(i.e. tsutsugamushi triangle). In recent years,scrub typhus cases and animal infection also emerged in Middle East,Africa,South America and even Europe. Given the increased incidence of scrub typhus in China,it is suggested to re-classified it as notifiable disease to reduce the disease burden in China.