RESPIRATORY VIRUSES
TECHNICAL UPDATE

DESCRIPTION/BACKGROUND INFORMATION:

Respiratory viruses are responsible for a significant portion of illness in the human population. Some viruses, such as influenza, are seasonal, while others predominantly affect specific age groups, such as RSV and Adenovirus. The rapid spread and high infectivity rates of respiratory viruses have been the trademark of many epidemics throughout the centuries. Respiratory viruses are of greatest concern in the young, aged, and immunocompromised patients where complication can potentially be severe.

CLINICAL APPLICATION:

Rapid and early diagnosis of respiratory disease is desirable. Antiviral therapy, if appropriate, can be instituted and antimicrobial therapy avoided. The two most widely used antiviral agents for respiratory viruses are amantadine/rimantadine and ribavarin.

Specific virus types are identified in the epithelial cells that line the nasal/bronchial passages using direct immunofluorescence. The DFA methodology uses fluorescin-labeled monoclonal antibody which binds to the viral antigen if present. Unbound antibody is removed by washing, and the remaining antibody-antigen complex is read microscopically.

Nasal washes and nasopharyngeal or tracheal aspirates should be collected from patients suspected of having a viral respiratory infection. Viral cells are best recovered from nasopharyngeal/nasal washes or tracheal aspirates. Viral transport media is kept for two weeks after DFA results are reported to allow viral culturing upon request. A negative result does not rule out presence of virus. The negative result may be due to factors such as: inadequate sample, improper collection or handling. Negative results should be carefully interpreted with regard to patient's clinical evaluation and other diagnostic tests.

Tests can be ordered individually or as a panel. Please see individual tests for preferred collection requirements.

TEST NAME & NUMBER:

• Adenovirus [DFA] (2471)
• Influenza A and B [Rapid] (2467)
• Influenza A and B [DFA] (2472)
• Parainfluenza 1, 2 and 3 [DFA] (2473)
• Respiratory Syncytial Virus (RSV) [Rapid] (2438)
• Respiratory Syncytial Virus (RSV) [DFA] (2464)
• Respiratory Virus Panel [DFA] (2470)

REFERENCES:

1. Murray, P.R., E.J. Baron, M.A. Pfaller, F.C. Tenover, and R.H. Yolken, editors. 1995. Chs. 70, 76-80. Manual of Clinic Microbiology, 6th edition. ASM, Washington, D.C.
2. Couch, R.B. and Six, H.R. (1986). The anti-viral spectrum and mechanism of action of amantadine and rimantadine. In: Anti-vrial Chemotherapy: New Directions for Clinical Application and Research. Mills, J., and Corey, I., (eds.). Elsevier Press, New York, p. 50.
3. Horwit, M. Adenoviruses. Ch. 61. In: Fields Virology, Second Edition, B.N. Fields, D.M. Knipe, et al. (eds.). Raven Press, New York, p. 1723.
4. Henderson, F.W., et al. (1982). A longitudinal study of respiratory viruses and bacteria in the etiology of acute otitis media with effusion. N. Engl. J. Med. 306:1377-1383.
5. McIntosh, K., et al. Enzyme linked immunosorbent assay for detection of respiratory syncytial virus infection: application to clinical samples. J. Clin. Microbiol. 16:329.