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Clinical features and phylogenetic analysis of Coxsackievirus A9 in Northern Taiwan in 2011

Yi-Chuan Huang1, Ying-Hsia Chu2, Ting-Yu Yen3, Wen-Chan Huang4, Li-Min Huang4, Ai-Ling Cheng4, Hurng-Yi Wang5 and Luan-Yin Chang4*

Author Affiliations

1 Division of Pediatric Infectious Disease, Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan

2 Department of Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan

3 Department of Pediatrics, China Medical University Hospital, China Medical University, Taichung, Taiwan

4 Department of Pediatrics, National Taiwan University Hospital, College of Medicine, National Taiwan University, No. 8 Chung-Shan South Road, Taipei, 10002, Taiwan

5 Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan

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BMC Infectious Diseases 2013, 13:33  doi:10.1186/1471-2334-13-33

Published: 24 January 2013



Coxsackievirus A9 (CA9) was one of the most prevalent serotype of enteroviral infections in Taiwan in 2011. After several patient series were reported in the 1960s and 1970s, few studies have focused on the clinical manifestations of CA9 infections. Our study explores and deepens the current understanding of CA9.


We analyzed the clinical presentations of 100 culture-proven CA9-infected patients in 2011 by reviewing their medical records and depicted the CA9 phylogenetic tree.


Of the 100 patients with culture-proven CA9 infections, the mean (SD) age was 4.6 (3.4) years and the male to female ratio was 1.9. For clinical manifestations, 96 patients (96%) had fever and the mean (SD) duration of fever was 5.9 (3.4) days. Sixty one patients (61%) developed a skin rash, and the predominant pattern was a generalized non-itchy maculopapular rash without vesicular changes. While most patients showed injected throat, oral ulcers were found in only 19 cases (19%), among whom, 6 were diagnosed as herpangina. Complicated cases included: aseptic meningitis (n=8), bronchopneumonia (n=6), acute cerebellitis (n=1), and polio-like syndrome (n=1). Phylogenetic analysis for current CA9 strains is closest to the CA9 isolate 27-YN-2008 from the border area of mainland China and Myanmar.


The most common feature of CA9 during the 2011 epidemic in Taiwan is generalized febrile exanthema rather than herpangina or hand, foot, and mouth disease. Given that prolonged fever and some complications are possible, caution should be advised in assessing patients as well as in predicting the clinical course.

Coxsackievirus A9; Enterovirus; Viral exanthema; Phylogenetic tree