Avian influenza at animal-human interface: One-health challenge in live poultry retail stalls of Chakwal, Pakistan

Background Live poultry retail stalls (LPRSs) are believed to be the source of human infection with avian influenza viruses (AIVs); however, little is known about epidemiology of these viruses in LPRSs of Pakistan. Objectives The current study was conducted to estimate the virological and serological prevalence of AIVs in humans and poultry and associated risk factors among seropositive butchers. Methods A field survey of LPRSs of Chakwal District was conducted between December 2015 and March 2016. In total, 322 samples (sera = 161 and throat swab = 161) from butchers and 130 pooled oropharyngeal swabs and 100 sera from birds were collected. Baseline sera (n = 100) from general population were also tested. Data were collected by structured questionnaires. Sera were tested by hemagglutination inhibition (HI) test further confirmed by micro-neutralization test (MN). Swabs were processed by real-time RT-PCR. Logistic regression analyses were conducted to identify risk factors. Results In butchers, 15.5% sera were positive for antibodies against H9 virus using a cutoff of >= 40 in HI titer; 6% sera from general population were positive for H9. Seroprevalence in poultry was 89%, and only 2.30% swabs were positive for H9. Presence of another LPRS nearby and the number of cages in the stall were risk factors (OR > 1) for H9 seroprevalence in butchers. Conclusions This study provides evidence of co-circulation of H9 virus in poultry and exposure of butchers in the LPRSs, which poses a continued threat to public health. We suggest regular surveillance of AIVs in occupationally exposed butchers and birds in LPRSs.