Saturday, August 13, 2011

Laboratory diagnosis of Rhinovirus

• Collection of specimens, viral isolation and cell culture
Specimens containing nasopharyngeal secretions are best for virus isolation. Maximal isolation frequencies were obtained on day 1-2 days of illness. Cell cultures of human origin are preferred; human embryonic fibroblast cell cultures, WI-38 strain and the MRC-5 strain of diploid fibroblasts, and HeLa cells have been used most extensively. Organ cultures of nasal and tracheal epithelium are required for growth of some fastidious rhinoviruses, but routine use of such cultures is impractical. Use of more than one type of cell culture is required for optimal isolation. Tissue cultures are observed frequently for CPE which are usually detected in the 1st week (Arruda et al., 1996).
• Serology
Serological diagnosis by demonstrating rising Ab titers is practicable only when the serotype of the infecting virus is known. The neutralization test has been widely used. The HI test is particularly useful for rapid screening of volunteers for Abs but can be used only for serotypes that hemagglutinate. This restriction does not apply to ELISA or CF tests (Minor, 2005).
• Molecular detection
Reports from a number of sources have now documented the fact that use of RT-PCR for detecting rhinoviruses invariably leads to higher numbers of proven infections. The increased proportion attributable to PCR has varied considerably, presumably because of varying sensitivity of the culture and PCR methods used

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