Epidemiologic and clinical features of non-polio enteroviral infections in northern Taiwan in 2008.

Background: Non-polio enteroviruses may cause different diseases, including herpangina, hand-foot-mouth disease (HFMD), meningitis, and nonspecific febrile illness; and cause epidemic outbreak annually. This study delineates the diversity of clinical presentations based on different serotypes and different groups [human enterovirus (HEV)-A and HEV-B] of enteroviruses (EVs) during the 2008 epidemic in National Taiwan University Hospital (NTUH).

Methods: We retrospectively identified patients younger than 18 years who had positive isolates of non-polio EV in throat swabs, rectal swabs, or cerebrospinal fluid, in NTUH from January 1 to December 31, 2008. For serotyping, immunofluorescence assay and polymerase chain reaction followed by viral structure protein-1 sequencing were applied. We analyzed and compared their clinical features among different serotypes and different groups of EVs.

Results: Among 172 patients who were enrolled, 16 serotypes were identified. The major serotype in NTUH was EV71 (25.6%) followed by coxsackievirus A (CA)16 and coxsackievirus B (CB)4. EV71 manifested mostly as HFMD (89%) and was complicated with encephalomyelitis in three patients. Serotypes of HFMD included EV71 (70%), CA16 (27%), CA4, and CA6. Serotypes of herpangina were heterogeneous, and the major serotype was CA2 (35.7%) followed by CB4 (23.8%). Aseptic meningitis was entirely caused by HEV-B and mostly infected by echovirus 30 (50%). Among children with EV-related respiratory tract infection, CB4 (32%) was dominant in upper respiratory tract infection, whereas echovirus 4 (71%) was the major cause of lower respiratory tract infection. Cases of HEV-A were significantly younger than the cases of HEV-B (p = 0.04). Multivariate analysis revealed that the most significant factor associated with hospitalization is HEV-B (odds ratio, 2.2; 95% confidence interval, 1.1-4.2; p = 0.02).

Conclusions: At least 16 serotypes circulated in northern Taiwan in 2008. EV71 is the predominant strain in this outbreak. All patients with HFMD were infected by HEV-A, but HEV-B was associated with a higher rate of hospitalization and aseptic meningitis, which should be a cause of alert regarding public health.