Detection of Human Influenza Viruses in Nasopharyngeal Samples by RT-PCR vs Tissue Culture

Influenza virus is a major pathogen involved in respiratory illnesses during winter seasons. A variety of diagnostic methods have been developed to identify influenza viruses in clinical specimen. Nasal and pharyngeal samples taken from patients were inoculated into Madin-Darby canine kidney (MOCK) cells and embryonated chicken eggs (ECEs). The culture media was assayed for hemagglutination (HA). Tissue culture supernatant and clinical specimens were used for RNA extraction, followed by reverse transcriptase-polymerase chain reaction (RT-PCR) using specific primers for influenza virus typing and subtyping. 21% of the samples were positive by RT-PCR while only 8.7% and 3.5% were positive by culturing in MOCK and ECE respectively. This study demonstrated that RT-PCR is more effective and sensitive than tissue culture for the diagnosis of influenza virus infection.