An important genus of trombiculid mites, formerly considered a subgenus of the genus Trombicula, which includes all of the vectors of scrub typhus (tsutsugamushi disease). Members of Leptotrombidium that serve as vectors of scrub typhus are within the Leptotrombidium deliense group: Leptotrombidium akamushi is the classical vector in Japan; Leptotrombidium deliense is the primary vector, extending from New Guinea, Australia, the Philippines, China, and Southeast Asia to western Pakistan; Leptotrombidium fletcheri is found in Malaysia, New Guinea, and the Philippines. Some eight other species have also been implicated in scrub typhus transmission in more limited areas.