Human Rhinovirus Infections in Rural Thailand: Epidemiological Evidence for Rhinovirus as Both Pathogen and Bystander

et al. (2011) Human Rhinovirus Infections in Rural Thailand: Epidemiological Evidence for Rhinovirus as Both Pathogen and Bystander. PLoS ONE 6(3): e17780. doi:10.1371/journal.pone.0017780 Human Rhinovirus Infections in Rural Thailand: Epidemiological Evidence for Rhinovirus as Both Pathogen and Bystander Alicia M. Fry 0 Xiaoyan Lu 0 Sonja J. Olsen 0 Malinee Chittaganpitch 0 Pongpun Sawatwong 0 Somrak Chantra 0 Henry C. Baggett 0 Dean Erdman 0 Benjamin Cowling, University of Hong Kong, Hong Kong 0 1 Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America, 2 Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America, 3 Division of Emerging Infections and Surveillance Services, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America, 4 National Institute of Health, Thailand Ministry of Public Health , Nonthaburi , Thailand , 5 International Emerging Infections Program, Thai MOPH-U.S.CDC Collaboration , Nonthaburi , Thailand Background: We describe human rhinovirus (HRV) detections in SaKaeo province, Thailand. Methods: From September 1, 2003-August 31, 2005, we tested hospitalized patients with acute lower respiratory illness and outpatient controls without fever or respiratory symptoms for HRVs with polymerase chain reaction and molecularlytyped select HRVs. We compared HRV detection among hospitalized patients and controls and estimated enrollment adjusted incidence. Results: HRVs were detected in 315 (16%) of 1919 hospitalized patients and 27 (9.6%) of 280 controls. Children had the highest frequency of HRV detections (hospitalized: ,1 year: 29%, 1-4 year: 29%, $65 years: 9%; controls: ,1 year: 24%, 1-4 year: 14%, $65 years: 2.8%). Enrollment adjusted hospitalized HRV detection rates were highest among persons aged ,1 year (1038/100,000 persons/year), 1-4 years (457), and $65 years (71). All three HRV species were identified, HRV-A was the most common species in most age groups including children aged ,1 year (61%) and all adult age groups. HRV-C was the most common species in the 1-4 year (51%) and 5-19 year age groups (54%). Compared to controls, hospitalized adults ($19 years) and children were more likely to have HRV detections (odds ratio [OR]: 4.8, 95% confidence interval [CI]: 1.5, 15.8; OR: 2.0, CI: 1.2, 3.3, respectively) and hospitalized children were more likely to have HRV-A (OR 1.7, CI: 0.8, 3.5) or HVR-C (OR 2.7, CI: 1.2, 5.9) detection. Conclusions: HRV rates were high among hospitalized children and the elderly but asymptomatic children also had substantial HRV detection. HRV (all species), and HRV-A and HRV-C detections were epidemiologically-associated with hospitalized illness. Treatment or prevention modalities effective against HRV could reduce hospitalizations due to HRV in Thailand. - Human rhinoviruses (HRVs) are members of the family Picornaviridae, genus Enterovirus, and comprise 3 species, HRV-A, HRV-B and the recently recognized HRV-C [1,2,3]. HRVs are a well established cause of the common cold, an upper respiratory illness characterized by rhinorrhea, nasal congestion, cough, sore throat and sneezing; more than half of upper respiratory illnesses are caused by HRVs [4]. Recently, several studies have suggested that HRVs may be associated with more severe illness, including hospitalized lower respiratory disease and asthma exacerbations [5,6] [7,8,9,10,11,12,13,14,15]. Also, some studies suggest that infection with HRV-C may result in more severe illness compared to illness with other species [1,2,16,17]. HRVs have also been identified among asymptomatic persons (detection in the nasopharynx in the absence of respiratory symptoms) as an innocent bystander virus [18]. The reported prevalence of HRV detection among asymptomatic persons ranges from 1222% among children and 9% among adults with immunocompromising conditions [19,20,21,22]. Consequently, the clinical relevance of detection of HRV among hospitalized patients can be difficult to interpret and better studies are needed to ascertain the role of HRVs as pathogens to spur efforts to develop treatment and prevention modalities. To that end, we took advantage of a study in rural Thailand that concurrently enrolled hospitalized patients with acute lower respiratory illness, a sample of outpatients with influenza-like illness, and control outpatients without fever or respiratory symptoms from the same hospitals to better define the etiologic role of HRV infection and associated disease burden in this community. The surveillance system and laboratory procedures have been published previously [23]. Briefly, residents of Sa Kaeo province, Thailand who were identified in active population-based surveillance for hospitalized acute respiratory illness were approached for enrollment into a pneumonia etiology study during September 1, 2003 through August 31, 2005. Enrollment occurred in all 8 (...truncated)