|KWON, JUNGHOON - Consultant|
|LEE, DONG-HUN - University Of Connecticut|
|CRIADO, MIRIA FERREIRA - Consultant|
|ALI, MD ZULFEKAR - Bangladesh Agricultural Research Institute|
|GIASUDDIN, MOHAMMAD - Bangladesh Agricultural Research Institute|
Submitted to: Virus Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2020
Publication Date: 6/13/2020
Citation: Kwon, J., Lee, D., Criado, M., Killmaster, L.F., Ali, M., Giasuddin, M., Swayne, D.E. 2020. Genetic evolution and transmission dynamics of clade 220.127.116.11a highly pathogenic avian influenza A/H5N1 viruses in Bangladesh. Virus Evolution. 6(2):veaa046. https://doi.org/10.1093/ve/veaa046.
Interpretive Summary: The deadly H5N1 form, high pathogenicity, of avian influenza viruses (HPAIVs) have been caused continuous poultry outbreak in Bangladesh since 2007, despite the use of vaccine. In this study, we analyzed gene information and mutations of the HPAIVs, to better understand how the viruses changed. Our analysis suggests that the major genotype has been replaced and domestic ducks in Bangladesh played a major role in persistence, spread, evolution and genotype replacement of HPAIVs in Bangladesh.
Technical Abstract: Asian lineage A/H5N1 highly pathogenic avian influenza viruses (HPAIVs) have been responsible for continuous outbreaks in Bangladesh since 2007. Although clades 2.2.2 and 18.104.22.168 HPAIVs have disappeared since poultry vaccination was introduced in 2012, clade 22.214.171.124a viruses have continued to be detected in Bangladesh. In this study, we identified A/H9N2 (n¼15), A/H5N1 (n¼19), and A/H5N1-A/H9N2 (n¼18) mixed viruses from live bird markets, chicken farms, and wild house crows (Corvus splendens) in Bangladesh from 2016 to 2018. We analyzed the genetic sequences of the H5 HPAIVs, to better understand the evolutionary history of clade 126.96.36.199a viruses in Bangladesh. Although seven HA genetic subgroups (B1–B7) and six genotypes (G1, G1.1, G1.2, G2, G2.1, and G2.2) have been identified in Bangladesh, only subgroup B7 and genotypes G2, G2.1, and G2.2 were detected after 2016. The replacement of G1 genotype by G2 in Bangladesh was possibly due to vaccination and viral competition in duck populations. Initially, genetic diversity decreased after introduction of vaccination in 2012, but in 2015, genetic diversity increased and was associated with the emergence of genotype G2. Our phylodynamic analysis suggests that domestic Anseriformes, including ducks and geese, may have played a major role in persistence, spread, evolution, and genotype replacement of clade 188.8.131.52a HPAIVs in Bangladesh. Thus, improvements in biosecurity and monitoring of domestic Anseriformes are needed for more effective control of HPAI in Bangladesh.