Disentangling the role of Africa in the global spread of H5 highly pathogenic avian influenza
Alice Fusaro, Bianca Zecchin, Bram Vrancken, Celia Abolnik, Rose Ademun, Abdou Alassane, Abdelsatar Arafa, Joseph Adongo Awuni, Emmanuel Couacy-Hymann, M.’ Bétiégué Coulibaly, Nicolas Gaidet, Emilie Go-Maro, Tony Joannis, Simon Dickmu Jumbo, Germaine Minoungou, Clement Meseko, Maman Moutari Souley, Deo Birungi Ndumu, Ismaila Shittu, Augustin Twabela, Abel Wade, Lidewij Wiersma, Yao P. Akpeli, Gianpiero Zamperin, Adelaide Milani, Philippe Lemey & Isabella Monne
The role of Africa in the dynamics of the global spread of a zoonotic and economically-important virus, such as the highly pathogenic avian influenza (HPAI) H5Nx of the Gs/GD lineage, remains unexplored. Here we characterise the spatiotemporal patterns of virus diffusion during three HPAI H5Nx intercontinental epidemic waves and demonstrate that Africa mainly acted as an ecological sink of the HPAI H5Nx viruses. A joint analysis of host dynamics and continuous spatial diffusion indicates that poultry trade as well as wild bird migrations have contributed to the virus spreading into Africa, with West Africa acting as a crucial hotspot for virus introduction and dissemination into the continent. We demonstrate varying paths of avian influenza incursions into Africa as well as virus spread within Africa over time, which reveal that virus expansion is a complex phenomenon, shaped by an intricate interplay between avian host ecology, virus characteristics and environmental variables.