Epidemiologic, clinical and laboratory features of scrub typhus in thirty Thai children.

BACKGROUND: Scrub typhus, a potentially fatal rickettsial infection, is common in Asia. Although serologic surveys suggested that as many as one-fourth of cases of scrub typhus might be in children, very few reports of childhood scrub typhus are available in the medical literature. OBJECTIVES: To document the clinical, laboratory and epidemiologic characteristics of pediatric patients with scrub typhus. METHODS: From January 1, 2000 to December 31, 2001, all pediatric patients at Chiang Mai University Hospital who had obscure fever for >5 days were tested for indirect immunofluorescent antibody (IFA) against Orientia tsutsugamushi, the causative organism of scrub typhus. Scrub typhus was diagnosed on the basis of either a single IFA titer against O. tsutsugamushi > or =1/400 or a 4-fold or greater rise in IFA titer to at least 1/200. RESULTS: Thirty children with scrub typhus were enrolled. Most were diagnosed during the rainy months of June to November. Common physical signs included lymphadenopathy (93%), hepatomegaly (73%), eschar (68%), conjunctival hyperemia (33%), maculopapular rash (30%) and splenomegaly (23%). Eleven patients had interstitial pneumonitis and 1 patient had meningitis. All patients responded well to doxycycline or chloramphenicol. The average interval to defervescence after treatment was 29 h (range, 6 to 72). CONCLUSIONS: Clinical and epidemiologic features of 30 pediatric patients with scrub typhus are reported in a prospective study. The presence of eschar was helpful in making the diagnosis. Complications included pneumonitis and meningitis. All cases responded well to treatment with antibiotic.