Abstract Title
High pathogenicity avian influenza A (H5N1) clade 2.3.2.1a virus in Indian flying fox (Pteropus medius) bats in Bangladesh
Abstract
High pathogenicity avian influenza (HPAI) outbreaks raise concerns due to pandemic potential, socioeconomic impact, and wildlife conservation risks. Here, we report unusual mortality of Indian flying fox (Pteropus medius) bat populations due to spillover of H5N1viruses. We monitored house crow (Corvus splendens) mortality events in Dhaka city between 2017 and 2024. During investigation, we observed crows and Indian flying fox bats cohabiting in the same roost and occasionally observed dead bats in the affected roosts. Aside from house crows, we found 16 Indian flying foxes infected with HPAI H5N1. We detected the H5N1 virus in tissue samples (trachea, kidney, liver, lungs, and brains) of these bats, indicating the systemic infection with H5N1 and could be the reason for the bats’ mortality, and potential risk of HPAI viruses to mammalian hosts. Phylogenetic analysis revealed that bat sequences belonged to the 2.3.2.1a clade, closely related to sequences from house crows and ducks in Bangladesh. The 2.3.2.1a clade comprises two major lineages: G1 and G2 and the bat sequences cluster within the G2 lineage indicating continuing evolution that has resulted in segregating multiple distinct subclusters in Bangladesh. We found bat H5N1 sequences contain several amino acid mutations and genetic markers of mammal adaptation. We report the first detection of H5N1 in bats in Bangladesh, concurrent with H5N1 in sympatric wild birds. Our findings suggest acute disease caused by the virus is likely cause of mortality events in bats cohabiting with infected crows. This underscores the potential of HPAI virus to cross host barriers and infect mammals, posing a significant public health concern.
Co-Author(s)
Ariful Islam1,5, Mohammad Enayet Hossain2, Emama Amin3 , Shariful Islam3, Md Arif Khan3, Abdullah Al-Mamun3, Sarah Munro4, Tahmina Shirin3, Mohammed Ziaur Rahman2, Marcel Klaassen5, Jonathan H Epstein4
1Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; 2One Health Laboratory, International Centre for Diarrheal Diseases Research, Bangladesh (icddr,b), Bangladesh; 3Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh; 4EcoHealth Alliance, New York, NY 10018, USA; 5School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
Abstract Category
Avian influenza in mammals, pandemic preparedness, and one health