Utilizing citizen science data to rapidly assess changing associations between wild birds and avian influenza outbreaks in poultry

Abstract

High pathogenicity avian influenza virus (HPAIV) is a rapidly evolving virus causing significant economic and environmental harm. Wild birds are a key viral reservoir and an important source of viral incursions into animal populations, including poultry. However, we lack a thorough understanding of which species drive incursions and whether this changes over time. We explored associations between the abundances of 152 avian species and outbreaks of highly pathogenic avian influenza (HPAI) in poultry premises across Great Britain between October 2021 and January 2023. Spatial generalized additive models were used, with species abundance distributions sourced from eBird. Associations were investigated at the species-specific level and across species aggregations. During autumn/winter, associations were generally strongest with waterbirds such as ducks and geese; however, we also found significant associations in groups such as non-native gamebirds and rapid change in species-specific associations over time. Our results demonstrate the value of citizen science to rapidly explore wild species as potential facilitators of disease incursions into well-monitored populations, especially in regions where viral surveillance in wild species is limited. This can be a critical step towards prioritizing targeted surveillance that could inform species-specific biosecurity measures; particularly for HPAIV, which has undergone sudden shifts in host range and continues to rapidly evolve.

Keywords: HPAIV; disease vector; eBird; spillover; viral incursion.

Figure 1.

HPAI cases in captive avian premises in Great Britain between 19 October 2021 and 20 January 2023. (a) Epidemic curve split into three distinct EPs (EP1 = 19 October 2021–9 February 2022; EP2 = 10 February 2022–16 August 2022; EP3 = 17 August 2022–20 January 2023). Number of cases per period were 86, 40 and 186, respectively. (b) Map of cases (red points) against a map of premises (black points) as listed in the Great British Poultry Register (jittered here to maintain anonymity).

Figure 2.

Estimated first-order group-level means for LM coefficients describing effects of weighted relative species abundance on probability of HPAI cases in premises. Estimated means derived from a GLM assessing group effects across EPs (EP1 = 19 October 2021–9 February 2022; EP2 = 10 February 2022–16 August 2022; EP3 = 17 August 2022–20 January 2023). N values above points indicate the number of species within each grouping. Error bars indicate the 95% confidence interval.

Figure 3.

Estimated second-order group-level means for LM coefficients describing effects of weighted relative species abundance on the probability of HPAI cases in premises. Estimated means derived from a GLM assessing group effects across EPs (EP1 = 19 October 2021–9 February 2022; EP2 = 10 February 2022–16 August 2022; EP3 = 17 August 2022– 20 January 2023). N values above points indicate the number of species within each grouping. BOP refers to the Birds of Prey grouping.

Figure 4.

Change in species-specific slope coefficient for the effect of weighted relative species abundance on case probability in premises across Great Britain. (a) EP2 compared with EP1. (b) EP3 compared with EP2. (c) EP3 compared with EP1. The dashed black line has a slope of 1 and indicates the relationship if there was no change between EPs. Solid black line is the actual line of best fit through points based on a LM. Error bars around points indicate standard error.

Figure 5.

Estimated means for change between EPs in the LM coefficients describing effects of weighted relative species abundance on the probability of HPAI cases in premises. Estimated means derived from a GLM assessing group effects (separate model for grouping 1 and grouping 2). Change is calculated as slope coefficient in EP3 minus slope coefficient in EP1. Bold text and thicker error bars indicate models under the coarsest species grouping (grouping 1).