Serological and Molecular Survey of Avian Influenza H9N2 Subtype in Live Birds Markets- 2016

Avian influenza is one of the most important diseases both economically and from a public health viewpoint.

To investigate the serological and molecular prevalence of AI-H9N2 in live bird markets, bird gardens, parks and zoos.

This cross-sectional study was conducted from August to December 2016.  In each unit, 40 blood samples from different bird species and 60 cloacal samples from waterfowl (ducks and geese) were taken. All sera samples were tested by HI for detection of antibodies against H9N2 virus. The birds with sera titer =>4 (log2) and units with at least one positive bird were considered as positive. Swab samples were tested by RT-PCR method using two pairs of primers to detect M and H9 gene of H9N2 virus.

2638 sera samples from birds in 127 units in 22 provinces and 3001 swab samples from duck and goose were taken. 73 units out of 127 (57.48 %; 95 % confidence interval, 66.2 % - 48.4 %) and 720 birds from a total of 2638 birds (27.29 %: 95 % confidence interval, 29.6 % - 25.6 %) were sero-positive. Among the bird species, the highest seroprevalence was 47.6 % and 45.3 % in turkey and chicken, respectively and the lowest seroprevalence was 13.8 % and 16.3 % for ducks and geese, respectively. 39 pooled samples from 18 units (14.75 %) were positive.

The results of this study showed high prevalence and circulation of avian influenza H9N2 viruses among poultry in these markets. Organizing the markets by improving the health and biosecurity of the markets, and it is necessary to educate the people and continuously surveillance the birds that offered in the markets to control the disease.