H9N2 Influenza A Viruses Found to be Enzootic in Punjab Pakistan´s Bird Markets with Evidence of Human H9N2 Nasal Colonization

Objective: This study sought to detect and characterize influenza A (IAV) and influenza D (IDV) viruses circulating among commercial birds and shop owners in Pakistan´s live bird markets.

Methods: Oropharyngeal swabs (n=600; n=300 pools) collected from poultry and nasopharyngeal swabs (n=240) collected from poultry workers were studied for molecular evidence of IAV and IDV using real-time and conventional RT-PCR protocols.

Results: Nineteen (6.3%) poultry pools were positive for IAV and 73.9% of these were positive for H9N2 subtypes. Two (0.83%) poultry workers had evidence of IAV, and both were also H9N2 subtypes. The poultry and human influenza A-positive specimens all clustered phylogenetically by Sanger and next-generation sequencing with previously detected H9N2 poultry isolates. No field specimens were positive for IDV.

Conclusion: H9N2 IAV is likely enzootic in Punjab Province Pakistan´s live bird markets and may be colonizing the noses of workers and market visitors. Regular monitoring for avian influenza-associated human illness in Punjab seems to be a needed public measure.