Volume 17, Number 8–August 2011
Research
Enterovirus 68 among Children with Severe Acute Respiratory Infection, the Philippines
Author affiliations: Tohoku University Graduate School of Medicine, Sendai, Japan (T. Imamura, N. Fuji, A. Suzuki, H. Oshitani); Tohoku-Research Institute for Tropical Medicine Collaborating Research Center on Emerging and Reemerging Diseases, Muntinlupa City, the Philippines (R. Tamaki, M. Saito, R. Aniceto); Eastern Visayas Regional Medical Center, Tacloban City, the Philippines (R. Aniceto); and Research Institute for Tropical Medicine, Muntinlupa City (H. Galang, L. Sombrero, S. Lupisan)
Suggested citation for this article
Abstract
Enterovirus 68 (EV68) is a rare enterovirus associated with respiratory illness that, unlike other enteroviruses, has been identified only from respiratory specimens. We identified EV68 from respiratory specimens of children hospitalized with a diagnosis of severe pneumonia in Leyte, Republic of the Philippines. Twenty-one samples showed high similarity with EV68 by sequencing of 5′ nontranslated region; 17 of these samples were confirmed as EV68 by sequencing of viral protein 1 capsid coding region. Most previously reported EV68 cases had been identified as sporadic cases. All 21 patients we identified had severe illness, and 2 died, possibly the first reported fatal cases associated with EV68 infection. Our study suggests that EV68 may be a possible causative agent of severe respiratory illnesses.
The genus Enterovirus (family Picornaviridae) contains 10 species: Human enterovirus (HEV) A, HEV-B, HEV-C, HEV-D, Simian enterovirus A, Bovine enterovirus, Porcine enterovirus B, Human rhinovirus (HRV) A, HRV-B, and HRV-C. To date, only 3 serotypes have been found for HEV-D: enterovirus 68 (EV68), EV70, and EV94. EV70 is associated with acute hemorrhagic conjunctivitis (1), and EV94, a newly found serotype in HEV-D, was identified among enteroviruses associated with acute flaccid paralysis (2,3). The first EV68 was isolated from hospitalized children with lower respiratory infection in California in 1962 (4). Since then, EV68 has been identified sporadically from respiratory specimens (5,6). EV68 is one of the most rarely isolated enteroviruses; only 26 strains were identified during 36 years of enterovirus surveillance in the United States (7). All documented EV68 to date have been reported from the United States and Europe (3–6); little epidemiologic information is available from Asia and nonindustrialized countries. The clinical significance of EV68 is also not well defined.
Enteroviruses are normally acid resistant and grow at an optimal temperature of ≈37°C, which enables enterovirus to amplify efficiently in the alimentary tract. However, EV68 shares the main characteristics of HRV, which is acid sensitive and grows at a lower optimal temperature (5,8). These characteristics may explain why EV68 had been isolated only from the respiratory tract (5). EV68 and HRV also share high similarity in the 5′ nontranslated region (5′ NTR) (5,8,9). We report a cluster of EV68 infections among hospitalized children with severe acute respiratory illness in the Eastern Viasayas Region of the Philippines during 2008–2009.
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Suggested Citation for this Article
Imamura T, Fuji N, Suzuki A, Tamaki R, Saito M, Aniceto R, et al. Enterovirus 68 among children with severe acute respiratory infection, thr Philippines. Emerg Infect Dis [serial on the Internet]. 2011 Aug [date cited]. http://www.cdc.gov/EID/content/17/8/101328.htm
DOI: 10.3201/eid1708.101328
Comments to the Authors
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Hitoshi Oshitani, Tohoku University Graduate School of Medicine, Department of Virology, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan; email: oshitanih@med.tohoku.ac.jp
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