Assessing the spatial risk of wild birds in avian influenza transmission using global risk score

Accumulated evidence supports the critical role of migratory wild birds in highly pathogenic avian influenza virus (HPAIV) spread and evolution. An effective surveillance strategy to study HPAIV dispersal in wild birds and identify critical interfaces between wild birds and poultry on the landscape for potential interspecies transmission and virus evolution will be essential. This study integrates conditional likelihood with epidemiological research designs to investigate the risk of poultry farm outbreaks due to the introduction of HPAIV by migratory birds from the Taiwan citizen scientist dataset. The prediction accuracy of poultry farm outbreaks was evaluated by employing the global risk score (GRS) of multiple species of wild birds under different significance level. Although 11 wild bird species demonstrated significant associations (P < 0.05) with HPAIV poultry farm outbreaks, the bird species with P < 0.1 yielded the optimal area under the receiver operating characteristic curve. Without prior adjustment of environmental factors, the posterior adjusted likelihood results suggested that the agricultural wetlands yield notably strong positive odds ratio estimates for all species. The GRS under adjustment of environmental factors, a linear combination of the 27 migratory species and 27 resident species, was 0.320, yielding a sensitivity of 0.81 and specificity of 0.77. The framework of GRS developed in this study can be applied to different countries for enhanced surveillance of HPAIV.