INTRODUCTION: From March through April of 2009, Mexico notified outbreaks of respiratory illness, due to a new influenza virus of swine origin, which spread over rapidly via human-to-human transmission. The molecular methods currently in use were not suitable because the genome composition based on gene segments of swine, avian and human origin was quite different from the influenza A virus (H1N1) circulating at that time. OBJECTIVE: Based on the published sequences, a set of specific primers for the HA gene was designed to evaluate a new RT-PCR assay. METHODS: The RT-PCR assay processed 3 197 clinical samples from suspected cases of pandemic influenza A (H1N1) infection. RESULTS: The novel optimized method obtained a 262 pb segment, without unspecific reactions. The new method proved to be useful in the diagnosis and subtyping of pandemic HINI influenza virus. The amplified product was verified by nucleotide sequencing, thus confirming the virus. CONCLUSIONS: The introduction of this new assay for the laboratory surveillance of influenza virus strengthens the diagnostic capacity of the National Reference Laboratory.
INTRODUCTION: From March through April of 2009, Mexico notified outbreaks of respiratory illness, due to a new influenza virus of swine origin, which spread over rapidly via human-to-human transmission. The molecular methods currently in use were not suitable because the genome composition based on gene segments of swine, avian and human origin was quite different from the influenza A virus (H1N1) circulating at that time. OBJECTIVE: Based on the published sequences, a set of specific primers for the HA gene was designed to evaluate a new RT-PCR assay. METHODS: The RT-PCR assay processed 3 197 clinical samples from suspected cases of pandemic influenza A (H1N1) infection. RESULTS: The novel optimized method obtained a 262 pb segment, without unspecific reactions. The new method proved to be useful in the diagnosis and subtyping of pandemic HINI influenza virus. The amplified product was verified by nucleotide sequencing, thus confirming the virus. CONCLUSIONS: The introduction of this new assay for the laboratory surveillance of influenza virus strengthens the diagnostic capacity of the National Reference Laboratory.