Maintenance of viability and comparison of identification methods for influenza and other respiratory viruses of humans

Abstract

A comparison of Hanks balanced salt solution, veal infusion broth (VIB) and charcoal viral transport medium for maintaining viability of type A influenza virus indicated approximately equal survival of virus on all 3 media at -70.degree. and 4.degree. C, but at 25.degree. C virus survived best in VIB. VIB supplemented with bovine serum albumin was used as transport medium in a community-wide surveillance of febrile respiratory disease for influenza viruses. Unfrozen [human] throat swab specimens were placed in VIB and stored at 4.degree. C for up to 5 days without effect on isolation frequencies of type A or type B influenza virus or type 1 or type 3 parainfluenza virus. Comparison of indirect immunofluorescence with hemadsorption for detection of type A influenza virus in rhesus monkey kidney cultures revealed a requirement for at least 5 fluorescing cells to eliminate false positive indirect immunofluorescence tests and at least 3 days of incubation to eliminate false negative tests when compared with hemadsorption at later times. Detection frequencies for the 2 methods after 2 and 3 days of incubation were not significantly different.