title: Human coronavirus infections in rural Thailand: a comprehensive study using real-time reverse-transcription polymerase chain reaction assays.
abstract: BACKGROUND
  We sought to determine whether infections with human coronaviruses (HCoVs) 229E, OC43, HKU1, and NL63 are associated with pneumonia and to define the epidemiology of HCoV infection in rural Thailand.
  
  
  METHODS
  We developed a real-time reverse-transcription polymerase chain reaction (RT-PCR) assay panel for the recognized HCoV types and compared HCoV infections in patients hospitalized with pneumonia, outpatients with influenza-like illness, and asymptomatic control patients between September 2003 and August 2005.
  
  
  RESULTS
  During study year 1, 43 (5.9%) of 734 patients with pneumonia had HCoV infections; 72.1% of the infections were with OC43. During study year 2, when control patients were available, 21 (1.8%) of 1156 patients with pneumonia, 12 (2.3%) of 513 outpatients, and 6 (2.1%) of 281 control patients had HCoV infections. Compared with infection in control patients, infection with any HCoV type or with all types combined was not associated with pneumonia (adjusted odds ratio for all HCoV types, 0.67 [95% confidence interval, 0.26-1.75]; P=.40). HCoV infections were detected throughout both study years; 93.6% of OC43 infections in the first year occurred from January through March.
  
  
  CONCLUSIONS
  HCoV infections were infrequently detected in rural Thailand by use of sensitive real-time RT-PCR assays. We found no association between HCoV infection and illness. However, we noted year-to-year variation in the prevalence of HCoV strains, which likely influenced our results.
authors.affiliation: Respiratory and Gastroenteritis Viruses Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Dare
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Fry
authors.forename: Malinee
authors.initials: M
authors.lastname: Chittaganpitch
authors.forename: Pathom
authors.initials: P
authors.lastname: Sawanpanyalert
authors.forename: Sonja J
authors.initials: SJ
authors.lastname: Olsen
authors.forename: Dean D
authors.initials: DD
authors.lastname: Erdman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D018352:Coronavirus Infections / Q000453:epidemiology* / Q000821:virology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011024:Pneumonia, Viral / Q000453:epidemiology / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012424:Rural Population; D012680:Sensitivity and Specificity; D013785:Thailand / Q000453:epidemiology