Disease/Syndrome

Typhus, mite-borne scrub

Category

Infection, Occupational

Acute/Chronic

Acute-Severe

Synonyms

Tsutsugamushi disease; Miteborne typhus fever; Orientia tsutsugumushi infection; Scrub typhus

Biomedical References

Search PubMed

Comments

INITIAL SYMPTOMS: Flu-like illness with fever, headache, myalgia, conjunctivitis, transient rash, eschar or eschars, and lymphadenopathy; [CCDM] FINDINGS: "Punched out" skin lesions (papules then eschars) appear at the sites of attachment of the infected mites. A rash appears on the trunk one week after onset of the fever in about 1/2 of patients. Pneumonitis is common and may progress to ARDS. Confusion or hearing loss may occur. In untreated cases, fever lasts for 14 days, and the case-fatality rate varies from 1% to 60%. [CCDM, p. 666] The rash starts on the trunk and spreads to the extremities, sparing palms/soles. Hepatosplenomegaly is common. [ID, p. 1488-9] Regional lymphadenopathy is usually present when the eschar appears. In a typical case, there is fever, rash, eschar, lymphadenopathy, and transient hearing loss in a patient 5-20 days after visiting an endemic area. Hematemesis and melena occur frequently. [Guerrant, p. 336] Some patients have elevated liver enzymes. Lymph nodes may be tender. Leukopenia occurs. Some patients have relapses. [Cecil, p. 1960] EPIDEMIOLOGY: Workers are infected in scrub-overgrown terrain or other mite-infested areas. In military operations in "typhus islands," a large percentage of troops may become infected. [CCDM, p. 667] Infected mites live in rural areas suitable for rodent populations. The chiggers feed on rodents, but do not infect them with O. tsutsugumushi.. [Guerrant, p. 334] Case-fatality rate is about 7%, but would be lower if all mild cases were diagnosed. [Harrison ID, p. 735] COMPLICATIONS: Rare complications are meningoencephalitis, convulsions, and coma. Pericarditis may develop. [Guerrant, p. 336] Findings may include delirium and myocarditis. [Merck Manual, p. 1285] The pale and transient, macular rash is reported in only about 30% of cases. In severe cases, the disease causes hemorrhages and multiple organ failure. Fatal complications include ARDS, shock, renal failure, DIC, and encephalitis. [PPID, p. 2498, 2529-30, 3643]

Latency/Incubation

6-21 days, usually 10-12 days; [CCDM]

Diagnostic

Serology (IFA, indirect immunoperoxidase, and enzyme immunoassays): PCR analysis of eschars and blood; [Harrison, p. 676]

ICD-9 Code

081.2

Effective Antimicrobics

Yes

Reference Link

CDC Travel - Rickettsial Infections

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