New York City (NYC) now has the largest number of confirmed cases in the U.S. The NYC Department of Health recommends testing only when people experience severe symptoms or fall sick in clusters. A negative rapid antigen, immunofluorescence or viral culture test does not rule out swine flu, according to the Centers for Disease Control and Prevention (CDC). Conversely, a suspected patient who tests positive for influenza A in a rapid antigen or immunofluorescent test, is considered a probable case of swine influenza A.
Confirmation requires a positive viral culture or a positive result of the molecular real-time polymerase chain reaction test (RT-PCR) for influenza A, B, H1 and H3 available in State Public Health Laboratories. This confirmatory test is indirect since even though the swine flu virus is type A(H1N1), the results are negative for H1. The direct confirmation test is currently only available at the CDC.
The nasal/pharyngeal swab used for the rapid flu antigen test might not be appropriate for the RT-PCR test. The later requires synthetic swab materials, viral transport media and transport at refrigerated or freezing (- 70 C) temperatures.
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Hello Sam R,
ReplyDeleteHow does this outbreak of the swine flu differ from the one in 1976?
Is it possible that the current viral strand is more resistant than in previous years?
I don't think we know enough about the current strain to compare it to other pandemic strains. The current swine flu virus seems to be sensitive to neuraminidase inhibitors, but there is always the possibility of emerging resistance after extensive use of these drugs.
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