Economical laboratory support system for influenza virus surveillance.

When increases in influenzalike illnesses were first detected during the 1984 to 1985 and 1985 to 1986 influenza seasons, throat swab specimens were mailed by physicians across the United States to one hospital laboratory, and each specimen was inoculated into a single tube of cell culture. Of 165 specimens, 52 (32%) were positive for influenza A or B virus within 3 days of receipt when tested by fluorescence microscopy, permitting positive results to be received by the physicians within 1 week on the average. Approximate direct cost was $16 per specimen.