Community Outbreak of Adenovirus, Taiwan, 2011

Tsung-Pei Tsou¹, Boon-Fatt Tan¹, Hsin-Yu Chang¹, Wan-Chin Chen, Yuan-Pin Huang, Chen-Yin Lai, Yen-Nan Chao, Sung-Hsi Wei, Min-Nan Hung, Li-Ching Hsu, Chun-Yi Lu, Pei-Lan Shao, Jung-Jung Mu, Luan-Yin Chang, Ming-Tsan Liu

, Li-Min Huang, and The Unknown Pathogen Discovery/Investigation Group

Author affiliations: Centers for Disease Control, Taipei, Taiwan (T.P. Tsou, W.C. Chen, Y.P. Huang, Y.N. Chao, S.H. Wei, M.N. Hung, L.C. Hsu, J.J. Mu, M.T. Liu); and National Taiwan University Hospital, Taipei (B.F. Tan, H.Y. Chang, C.Y. Lai, C.Y. Lu, P.L. Shao, L.Y. Chang, L.M. Huang)

Abstract

In 2011, a large community outbreak of human adenovirus (HAdV) in Taiwan was detected by a nationwide surveillance system. The epidemic lasted from week 11 through week 41 of 2011 (March 14–October 16, 2011). Although HAdV-3 was the predominant strain detected (74%), an abrupt increase in the percentage of infections caused by HAdV-7 occurred, from 0.3% in 2008–2010 to 10% in 2011. Clinical information was collected for 202 inpatients infected with HAdV; 31 (15.2%) had severe infection that required intensive care, and 7 of those patients died. HAdV-7 accounted for 10%, 12%, and 41% of infections among outpatients, inpatients with nonsevere infection, and inpatients with severe infection, respectively (p<0 .01=".01" 2="2" a="a" absence="absence" an="an" and="and" are="are" caused="caused" china="china" circulating="circulating" detected="detected" dv7-hz="dv7-hz" emerging="emerging" factors="factors" hadv-7="hadv-7" identical="identical" in="in" introduction="introduction" is="is" of="of" outbreak.="outbreak." outbreak="outbreak" p="p" people="people" previous="previous" recently="recently" reported="reported" republic="republic" s="s" strain="strain" that="that" the="the" this="this" to="to" years="years">

Human adenoviruses (HAdVs) are DNA viruses that can cause a variety of human diseases. Since the discovery of these viruses in 1953, more than 50 types have been isolated, some directly linked to specific human diseases, e.g., infantile diarrhea (HAdV 40, 41), epidemic keratoconjunctivitis (HAdV 8, 19, 37, 54), and hemorrhagic cystitis (HAdV 11, 21) (1–3). Adenoviruses also are common causes of lower respiratory tract infections in children (4), but surveillance for these infections is lacking in most countries. Pneumonia caused by adenoviruses cannot be easily differentiated from other types of viral pneumonia, and culturing and typing of adenoviruses is not routinely performed in hospital or public health laboratories. Therefore, community-wide outbreaks of adenovirus are not easily detected; previous reports are limited to those occurring in hospital, school, or military settings (5–7).
In 1999, after a 1998 enterovirus 71 epidemic, the Taiwan Centers for Disease Control established a nationwide surveillance system using contract virologic laboratories (CVLs) to perform continuous virologic surveillance for respiratory viruses, especially influenza and enteroviruses (8). The network consists of 12 CVLs located in the northern, central, southern, and eastern regions of Taiwan (9). Early in 2011, the percentage of adenovirus isolated among all respiratory virus isolates evaluated by the CVLs increased from a baseline of 0%–5% to 10% and remained high in the following weeks, indicating a community-wide adenovirus outbreak. The apparent outbreak prompted us to use several existing surveillance systems to describe the characteristics of this outbreak.