The association between respiratory viruses and symptoms in 2-week-old infants at high risk for asthma and allergy.
OBJECTIVE
The role of viral respiratory tract infections in the onset of childhood asthma and allergy is controversial, partly because of limited understanding about postnatal viral exposures. We investigated the prevalence of 3 common respiratory viruses and associated respiratory symptoms in 2-week-old infants at high risk for having asthma and allergy.


METHODS
Frozen nasal specimens from 2-week-old children at high risk (n = 495) underwent reverse transcription-polymerase chain reaction (RT-PCR) for picornavirus-, parainfluenza-, and respiratory syncytial virus-specific nucleic acid. RT-PCR findings were related to respiratory symptoms (cold, cough, and wheeze) and to characteristics implicated with increased risk for asthma and allergy.


RESULTS
Viral RT-PCR was positive in 199 (40.2%) of 495 specimens examined, with picornavirus and parainfluenza significantly associated with respiratory symptoms. Viral prevalence was significantly higher in children born during the winter and summer months.


CONCLUSIONS
A high percentage (40.2%) of infants at high risk for asthma and allergy had been exposed to common respiratory viruses at 2 weeks of age. RT-PCR is a powerful diagnostic method that can be used in epidemiologic studies examining the role of viral respiratory tract infections in the pathogenesis of pediatric asthma and allergy.
Hegele
R G
RG
McDonald Research Laboratories, Department of Pathology and Laboratory Medicine, St Paul's Hospital, 1081 Burrard St., Vancouver, BC, Canada, V6Z 1Y6.
Ahmad
H Y
HY
Becker
A B
AB
Dimich-Ward
H
H
Ferguson
A C
AC
Manfreda
J
J
Watson
W T
WT
Chan-Yeung
M
M
D001249:Asthma / Q000209:etiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010849:Picornaviridae / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012130:Respiratory Hypersensitivity / Q000209:etiology*; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000150:complications*; D018108:Respirovirus / Q000302:isolation & purification; D012306:Risk; D014777:Virus Diseases / Q000150:complications*