ABSTRACT
Many studies in the past 8 years have used the PCR assay to detect respiratory virus infections. Many of the earlier studies used the assay to detect virus in laboratory cell cultures, and a few tested for virus infections in large numbers of clinical samples. The sensitivity of in vitro amplification of viral nucleic acid generally compares favorably with virus cell culture and other methods of antigen detection such as IF assays for many respiratory viruses. Nucleic acid amplification does not require virus viability, whereas many viruses cannot be grown in cell culture or may grow slowly, requiring days or weeks for identification. In the long run, in vitro amplification by PCR is cost effective and has recently been shown to reduce overall health costs in detecting RS virus in children admitted to hospital with acute respiratory illnesses (54). Genomic sequence variation, detectable because of the specificity of nucleotide base pairing during hybridization, can provide useful information about virus strain specificity, useful for both early diagnosis and epidemiological surveillance. DNA is generally resistant to organic solvents and other extreme physical conditions and can therefore be used to test for infection in stored samples several years after they are first collected.
