Do contrasting patterns of migration movements and disease outbreaks between congeneric waterfowl species reflect differing immunity?

Long-distance migrations influence the dynamics of host pathogen interactions and understanding the role of migratory waterfowl in the spread of the highly pathogenic avian influenza viruses (HPAIV) is important. While wild geese have been associated with outbreak events, disease ecology of closely related species has not been studied to the same extent. The swan goose (Anser cygnoides) and the bar-headed goose (Anser indicus) are congeneric species with distinctly different HPAIV infection records; the former with few and the latter with numerous records. We compared movements of these species, as well as the more distantly related whooper swan (Cygnus cygnus) through their annual migratory cycle to better understand exposure to HPAIV events and how this compares within and between congeneric and non congeneric species. In spite of their record of fewer infections, swan geese were more likely to come in contact with disease outbreaks than bar-headed geese. We propose two possible explanations: i) frequent prolonged contact with domestic ducks increases innate immunity in swan geese, and/or ii) the stress of high -elevation migration reduces immunity of bar-headed geese. Continued efforts to improve our understanding of species-level pathogen response is critical to assessing disease transmission risk.

Automated summary

By comparing the migration patterns and infection records of different species, it was found that despite having fewer infection records, swan geese were more likely to come in contact with disease outbreaks, while bar-headed geese were the opposite. This may be due to swan geese having frequent contact with domestic ducks, increasing their innate immunity, or the stress of high-elevation migration reducing the immunity of bar-headed geese.