Di Genova, C.; Warren, C. J.; Johnson, S.; Riccio, S.; Roper, K.; Thomas, S. S.; Schlachter, A.-L.; Jorge, D.; Ralh, K.; Hassan, J.; Billington, E.; Brown, I. H.; Slomka, M. J.; Banyard, A. C.; James, J.

The ongoing panzootic of H5N1 high pathogenicity avian influenza virus (HPAIV) has caused the deaths of over half a billion wild birds and poultry, and has led to spillover events in both wild and domestic mammals, alongside sporadic human infections. A key driver of this panzootic is the apparent high viral fitness across diverse avian species, which facilitates an increased interface between wild and domestic species. Columbiformes (pigeons and doves) are commonly found on poultry premises and are highly connected to humans in urban settlements, yet relatively little is known about their potential role in contemporary HPAIV disease ecology. Here we investigated the epidemiological role of pigeons (Columba livia) by determining their susceptibility using decreasing doses of clade 2.3.4.4b H5N1 HPAIV (genotype AB). We investigated infection outcomes and transmission potential between pigeons and to chickens for each dose. Following direct inoculation, pigeons did not develop clinical signs, and only those inoculated with the highest dose shed viral RNA or seroconverted to H5N1-AB, revealing a MID50 of 10^5 EID50. Even in the high dose group, only low-level shedding and environmental contamination was observed, and low-level viral RNA were present in the tissues of directly inoculated pigeons, with no distinct pathological lesions. Pigeons did not transmit the virus to naive pigeons or chickens placed in direct contact. Overall, these findings suggest that pigeons have a low susceptibility to clade 2.3.4.4b H5N1 HPAIV and are less likely to significantly contribute to disease ecology, incursions into poultry, or pose a significant zoonotic threat.