This Publication Is Searchable The Merck Manual of Diagnosis and Therapy Section 13. Infectious Diseases Chapter 159. A mite-borne disease caused by Rickettsia tsutsugamushi and characterized by fever, a primary lesion, a macular rash, and lymphadenopathy. Etiology and Epidemiology R. tsutsugamushi is transmitted in nature by trombiculid mites, which feed on forest and rural rodents, including rats, voles, and field mice.
Scrub typhus occurs in the Asiatic-Pacific area bounded by Japan, India, and Australia.
Sporadic cases have occurred in Americans, particularly those who visit northern Thailand or India. At onset of fever, an eschar often develops at the site of the chigger bite. Headache is severe and common, as is conjunctival injection. A macular rash develops on the trunk during the 5th to 8th day of fever, often extending to the arms and legs. It may disappear rapidly or become maculopapular and intensely colored.