Milder clinical manifestation of scrub typhus in Kinmen, Taiwan.

BACKGROUND/PURPOSE: Kinmen, an offshore island of Taiwan, is a popular location for sightseeing and an important entry port between Taiwan and China. Kinmen is also highly endemic for scrub typhus. The authors aimed to investigate the disease characteristics there, which remained largely unknown.

METHODS

The authors conducted a retrospective study on patients with scrub typhus in Kinmen during 2005-2008. The clinical information was reviewed from medical records for statistical analysis.

RESULTS

There were 261 patients with scrub typhus included with a bimodal summer-autumn type of distribution, with most patients (40%) age 20-29 years and a large proportion of patients (26%) older than 60 years. The disease manifestation, laboratory examinations, and treatment outcomes were comparable in summer and autumn. Fever (97%), eschar (93%), and relative bradycardia (67%) were the most common presentations, whereas lymphadenopathy (18%) and skin rash (8%) were infrequent. Elevated liver function, C-reactive protein levels, and low to normal platelet counts were frequent findings. A correct diagnosis was made made in an average 3.7 days after fever or 1.6 visits of medical consultation, and minocycline was prescribed in a timely manner. Most patients had good recovery and only 12 patients (5%) had severe infection with acute renal failure, shock, gastrointestinal bleeding, or respiratory failure; no mortality was found. Older age, longer fever duration, thrombocytopenia, abnormal liver and renal function, hyponatremia, and elevated C-reactive protein levels were significantly associated with severe complications and prolonged treatment duration.

CONCLUSION

A unique summer-autumn type of scrub typhus with milder disease manifestations is identified in Kinmen. The younger patient population, rapid diagnosis, and prompt treatment may be associated with a shortened disease course and lead to a better outcome.