title: Distribution and seasonality of rhinovirus and other respiratory viruses in a cross-section of asthmatic children in Trinidad, West Indies.
abstract: BACKGROUND
  Childhood asthma in the Caribbean is advancing in prevalence and morbidity. Though viral respiratory tract infections are reported triggers for exacerbations, information on these infections with asthma is sparse in Caribbean territories. We examined the distribution of respiratory viruses and their association with seasons in acute and stable asthmatic children in Trinidad.
  
  
  METHODS
  In a cross-sectional study of 70 wheezing children attending the emergency department for nebulisation and 80 stable control subjects (2 to 16 yr of age) in the asthma clinic, nasal specimens were collected during the dry (n = 38, January to May) and rainy (n = 112, June to December) seasons. A multitarget, sensitive, specific high-throughput Respiratory MultiCode assay tested for respiratory-virus sequences for eight distinct groups: human rhinovirus, respiratory syncytial virus, parainfluenza virus, influenza virus, metapneumovirus, adenovirus, coronavirus, and enterovirus.
  
  
  RESULTS
  Wheezing children had a higher [chi(2 )= 5.561, p = 0.018] prevalence of respiratory viruses compared with stabilized asthmatics (34.3% (24) versus (vs.) 17.5% (14)). Acute asthmatics were thrice as likely to be infected with a respiratory virus (OR = 2.5, 95% CI = 1.2 - 5.3). The predominant pathogens detected in acute versus stable asthmatics were the rhinovirus (RV) (n = 18, 25.7% vs. n = 7, 8.8%; p = 0.005), respiratory syncytial virus B (RSV B) (n = 2, 2.9% vs. n = 4, 5.0%), and enterovirus (n = 1, 1.4% vs. n = 2, 2.5%). Strong odds for rhinoviral infection were observed among nebulised children compared with stable asthmatics (p = 0.005, OR = 3.6, 95% CI = 1.4 - 9.3,). RV was prevalent throughout the year (Dry, n = 6, 15.8%; Rainy, n = 19, 17.0%) and without seasonal association [chi(2 )= 0.028, p = 0.867]. However it was the most frequently detected virus [Dry = 6/10, (60.0%); Rainy = 19/28, (67.9%)] in both seasons.
  
  
  CONCLUSIONS
  Emergent wheezing illnesses during childhood can be linked to infection with rhinovirus in Trinidad's tropical environment. Viral-induced exacerbations of asthma are independent of seasons in this tropical climate. Further clinical and virology investigations are recommended on the role of infections with the rhinovirus in Caribbean childhood wheeze.
authors: Department of Para-Clinical Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago.
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