Epidemiology and molecular characterization of co-circulating influenza A/H3N2 virus variants in children: Houston, Texas, 1997-8.
Co-circulating variants of influenza A/H3N2 viruses in children were studied in Houston, Texas between October 1997 and March 1998 to assess the effects of a new variant strain on the severity of clinical illness. Influenza A virus was isolated from the nasal wash or nasal aspirate specimens collected from children at two tertiary care hospitals, and 271 isolates were available for variant-specific subtyping using RT-PCR and restriction fragment length polymorphism (RFLP) analysis. We classified 124 (46%) influenza viruses as A/H3N2/Wuhan/359/95-like and 137 (50%) as A/H3N2/Sydney/05/97-like. Ten (4%) virus isolates could not be classified. Ill contacts in the household were reported more frequently in patients infected with A/Sydney-like viruses than in those infected with A/Wuhan-like viruses (85% vs. 71%, respectively, P=0.02). There were no differences in other demographic variables among children infected with these strains. This study found no increase in illness severity in children infected with a newly emerging strain.
O'Donnell
F T
FT
The University of Texas-Houston School of Public Health, 1200 Hermann Pressler Street, Houston, TX 77030, USA.
Munoz
F M
FM
Atmar
R L
RL
Hwang
L Y
LY
Demmler
G J
GJ
Glezen
W P
WP
D002648:Child; D002675:Child, Preschool; D021821:Communicable Diseases, Emerging / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D015897:Comorbidity; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000145:classification* / Q000235:genetics*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D008297:Male; D017720:Molecular Epidemiology; D015999:Multivariate Analysis; D016017:Odds Ratio; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D016016:Proportional Hazards Models; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology