Unusual crow (Corvus splendens) mortality event in Jessore, Bangladesh 2018

Background: Based on the national media report on unusual crow mortality in the premise of a secondary school, in Jessore district of Bangladesh. Country has reported crow deaths of Influenza A/H5, a multidisciplinary team investigated the outbreak from December 21st to 27th, 2018 to identify the etiologic agent, characterize the extent of the outbreak, and identify the source and recommended control measures.
Methods & Materials: We surveyed crow roosts around the school and observed the crows feeding and roosting behavior. We interviewed and evaluated live bird traders and workers, school teachers, students for fever and cough symptoms in last the 15 days. Team also evaluated the poultry waste disposal and cleaning practices in Live Birds Markets (LBMs). We collected cloacal and oropharyngeal swabs from moribund and dead crows and roost fecal samples under beneath the crow roosts, and environmental feces samples from five LBMs within five kilometers radius of the infected crow roost. All the samples were tested by real-time RT-PCR for Influenza-A (M gene) and for H5, H7 and H9.
Results: We found 24/31(77.4%) dead, and moribund crow swabs were positive for Influenza A/H5 virus, and 1/17(6%) environmental feces samples were positive for flu A/untypable. We found 2/18(11%) feces samples of LBMs were positive for A/H5 and 5.5% had influenza A H5/H9 co-infection. None of the crow samples were positive for H7 or H9 and LBMs samples for H7. We did not find any human cases among 234 participants during our investigation period. We observed the poultry sellers thrown offal and poultry wastage in a nearest water body like river, pond, and crows feed on poultry offal and waste materials from there.
Conclusion: The study reveals that the influenza virus is circulating in the contaminated LBMs environment and crows; and may be transmitted to crows through feeding on dead poultry and waste in LBMs. Continuous surveillance in wild birds and LBMs is recommended to know the virus evolution, transmission pathways and potential source of infection in crows, as well as, improved waste management practice of LBMs, public awareness is needed to reduce the risk of influenza virus spillover to human in Bangladesh.