Infestation with Trombiculid Mite Larvae

Abstract

Harvest mites are the larvae of trombiculid mites (see Table 22.1 for other common names). They have been a known cause of skin irritation, often very severe, for a long time and have a worldwide distribution. The first species to be identified, now called Neotrombicula autumnalis, was described in 1790 by Shaw. In 1834 it was recognised by Duges as the larval form of a mite (Toomey 1921). The adult stages are seldom seen, although a great deal of investigation about them has been done. Womersley and Heaslip (1943), in their comprehensive review of Far Eastern trombiculids, noted that only two of 15 species were fully documented in larval, nymphal and adult forms. Because of this they are classified on the basis of the morphology of the larvae (Finnegan 1945). Certain species in the Far East (Leptotrombidium akamushi and L. deliense) are known to be vectors of Japanese river fever (scrub typhus, rickettsial typhus, tsutsugamushi fever).