Most Common Causative Agents of Respiratory Disease

URI Parainfluenza, adenovirus, influenza, rhinovirus

Pharyngitis Adenovirus, parainfluenza, coxsackie

Croup Parainfluenza, respiratory syncytial

Bronchitis Parainfluenza, respiratory syncytial

Bronchiolitis Respiratory syncytial, parainfluenza

Pneumonia Respiratory syncytial, parainfluenza, adenovirus,influenza

Fry et al, CID 2006

The latest graph of virus activity in the Bay Area, asof November 19, as measured by identifications inthe UCSF Clinical Virology Laboratory, is attached;it can also be found at the following website:

http://labmed.ucsf.edu/images/graphs/viruses.gif

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Influenza A Virus Structure

Natural History of Influenza Viruses

Topley and Wilson’s Microbiology and Microbial Infections. 9th ed, Vol 1, Virology. Mahy and Collier, eds, 1998, Arnold, page 387, with permission.

1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

B

H3N2

H1N1

H2N2

H3N8

H2N?

H1N1

Serum antibody prevalenceVirus isolation

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Diagnostic Approaches for Influenza

Type of Test Indications for Use Lab Turnaround Time

Symptoms + epidemiology

“Classical symptoms” during influenza season -

Antigen-based rapid tests

Nonclassical symptoms, in season Classical symptoms, shoulder season (point of care)

<30 minutes

Direct fluorescent antibody (DFA) As antigen-based tests 0.5-3 hours

PCR When maximal sensitivity desired 6-24 hours

Culture Confirm antigen/DFA; obtain isolates for surveillance 24-48 hours

Ison, et al. Antiviral Res. 2002(55):227-278.

Positive Direct Fluorescent Antibody Test

Direct FA for Respiratory Viruses

Virus # Sens %Spec %PPV NPV

RSV 86 97 94 93

Flu A 86 99 97 99

Flu B 65 98 90 89

Para 1 52 100 100 99

Para 3 85 99 79 99

Respiratory PCR PanelInfluenza A - H3 N2

H1 N1 B

RSV A B

Para 1-4

AdenoMetapneumoRhinoEnteroCoronaSars

Covalciuc, et al.; J. Clin Micro 1999.

Weinstock and ZucottiJAMA, 2009

Antiviral Resistance in “Swine” Influenza H1N1

Adamantanes - Resistant

Oseltamivir - Susceptible (202/202, US, 3 resistant isolates outside US)

Zanamivir - Susceptible (including 3 oseltamivir resistant)

Recommended Rx - oseltamivir or zanamivir

     Isolates tested (n)

Resistant Viruses,Number (%)

Isolates tested (n)

Resistant Viruses,

Number (%)

    Oseltamivir Zanamivir   Adamantanes

Influenza A (H1N1) 88 86 (98%) 0 (0) 88 0 (0%)

Influenza A (H3N2) 14 0 (0) 0 (0) 14 14 (100%)

Influenza B 40 0 (0) 0 (0) N/A* N/A*

*Data from CDC, last updated 1/3/09