Typing and subtyping clinical isolates of influenza virus using reverse transcription-polymerase chain reaction

Background: Influenza virus infections are a major cause of morbidity and the identification of the type or subtype of a clinical isolate has important clinical and epidemiological implications.

Objectives: To evaluate the ability of a reverse transcription-polymerase chain reaction (RT-PCR) assay to type and subtype clinical human isolates of influenza virus.

Study design: Reference strains of influenza $\text{A}\text{H1N1}$, $\text{A}\text{H3N2}$, and B viruses and human clinical isolates of influenza virus representing antigenic variants from the last 15 years were evaluated using an RT-PCR assay.

Results: Amplicons of 325, 198 and 365 base pairs in length were obtained from RNA extracted from influenza $\text{A}\text{H1N1}$, $\text{A}\text{H3N2}$ and B viruses, respectively. All human-derived $\text{A}\text{H1N1}$, $\text{A}\text{H3N2}$, and B reference strains and antigenic variants tested were correctly identified.

Conclusions: RT-PCR is an effective alternative to traditional methods for typing and subtyping influenza viruses.