The difference in clinical characteristics between acute Q fever and scrub typhus in southern Taiwan.

Objective: To identify the differences in clinical characteristics between acute Q fever and scrub typhus in southern Taiwan.

Methods: A prospective observational study was conducted in which serological tests for acute Q fever and scrub typhus were performed simultaneously regardless of which disease was suspected clinically. From April 2004 to December 2007, 80 and 40 cases of serologically confirmed acute Q fever and scrub typhus, respectively, were identified and included in the study for comparison.

Results: By univariate analysis, being male (p<0.001) and having an alanine aminotransferase (ALT) >88U/l (p=0.015) were more common in acute Q fever, whereas residence or travel in a mountainous region or offshore island of Taiwan (p<0.001), skin rash (p<0.001), eschar (p<0.001), lymphadenopathy (p=0.04), leukocytosis (p=0.002), and pulmonary involvement on chest X-ray (p=0.003) were more common in scrub typhus. In the multivariate analysis, being male (odds ratio (OR) 10.883, 95% confidence interval (CI) 2.079-56.441, p=0.005) was an independent characteristic of acute Q fever, while residence or travel in a mountainous region or offshore island (OR 0.073, 95% CI 0.019-0.275, p<0.001) and skin rash (OR 0.152, 95% CI 0.024-0.945, p=0.043) were independent characteristics of scrub typhus. The response to doxycycline treatment was not different.

Conclusions: In southern Taiwan, sex, area of residence, travel history, and physical examination are important in the differentiation of acute Q fever from scrub typhus.