恙虫病，又称丛林斑疹伤寒，顾名思义为一种恙虫所传播的发热出疹性疾病，带有恙虫东方体（Orientia tsutsugamushi）。被恙虫叮咬过后，并经由其唾液使宿主感染立克次体的急性发热性疾病。老鼠是恙虫最常见之宿主。

具体来说，恙虫病主要是经由某些恙螨的品种，特别是主要在浓密的灌木丛植被里生活的纤恙螨（Leptotrombidium deliense，又名「沙蚤」）；其他相关的品种还包括：L. akamushi, L. arenicola, L. fletcheri, L. pallidum 及 L. pavlovsky。一旦被这些恙螨咬过后，会在皮肤上留下具明显特征的黑色焦痂，对医生作出诊断非常有用。

Scrub typhus or bush typhus is a form of typhus caused by the intracellular parasite Orientia tsutsugamushi, a Gram-negative α-proteobacterium of family Rickettsiaceae first isolated and identified in 1930 in Japan.

Although the disease is similar in presentation to other forms of typhus, its pathogen is no longer included in genus Rickettsia with the typhus bacteria proper, but in Orientia. The disease is thus frequently classified separately from the other typhi.