Encephalitis in Taiwan: a prospective hospital-based study.

To investigate encephalitis in Taiwan, a multicenter study was conducted with patients who had acute severe neurological dysfunction and suspected encephalitis from May 2000 to December 2001. Demographic data such as age, sex, and seasons were analyzed. Polymerase chain reaction analyses were performed to determine the microbiologic diagnosis. The patients included 73 males and 54 females, with a peak age of 10-40 years old. Microbiologic diagnoses in 86 (69%) of 124 cases involved herpes simplex virus (HSV, 45 cases), varicella zoster (16 cases), Mycobacterium tuberculosis (10 cases), cytomegalovirus (8 cases), adenovirus (5 cases), influenza (1 case), and enterovirus (1 case). Pathogens were found in 69% of the cases. Encephalitis was most likely to occur in June and July. Based on the results, HSV is still the major viral cause of encephalitis in Taiwan.