High pathogenicity avian influenza H5N1 clade 2.3.4.4b has caused a panzootic of devastating impact to poultry and wildlife globally. The Australian continent and broader Oceania until recently remained the last major region without confirmed detections. Here we report the first H5N1 clade 2.3.4.4b detections from two live seabirds - a brown skua and a southern giant petrel - found on the south coast of Western Australia in June 2026. Virus genome sequencing showed that both viruses were most closely related to H5N1 viruses detected recently on sub-Antarctic islands in the Southern Indian Ocean. In time-calibrated phylogeographic analyses, both viruses sampled in Western Australia clustered with viruses from Heard Island, a sub-Antarctic external territory of Australia. Ancestral location reconstruction also identified Heard Island as the most probable source location, although unsampled intermediate locations cannot be excluded. The two Western Australian detections were estimated to be independent incursions from Heard Island, rather than local transmission on mainland Australia. There was no evidence of reassortment with endemic avian influenza viruses in Australia, and both virus sequences retained key avian-like genetic markers and lacked known substitutions for reduced antiviral susceptibility. These detections revealed a Southern Ocean pathway of recurrent H5N1 incursions into Australia, highlighting the risk of potential establishment on the mainland and the need for heightened surveillance and rapid, nationally-coordinated, virus genomic characterisation.
Matthew J. Neave, S. Hair, Patrick Mileto et al.· bioRxiv· 0 citations
BACKGROUND
Rodent-borne pathogens pose important global health risks, yet national-scale assessments linking host-pathogen ecology with disease dynamics remain limited, particularly in China.
METHODS
We compiled global (>29,000 records) and China-specific (2,235 records; 1950-2023) rodent-pathogen datasets to characterize host-pathogen networks, identify hyperreservoirs, and quantify prevalence heterogeneity using hierarchical meta-regression. We applied a two-layer framework integrating 1-km host suitability surfaces (stacking ensemble of boosted regression trees and random forest models) with province-level disease inference using generalized linear models for hemorrhagic fever with renal syndrome (HFRS), leptospirosis, and plague. Human exposure was estimated by overlaying suitability with gridded population data.
RESULTS
Globally, 116 pathogens of concern were identified across 206 host species, including 30 spillover-risk viruses and 34 hyperreservoirs. Meta-regression identified sample source as the only consistently robust moderator of prevalence heterogeneity; other moderators (e.g., rodent family, region, and habitat type) showed inconsistent or non-robust associations. Host suitability was positively associated with HFRS incidence (incidence rate ratio = 1.36, P < 0.01) but negatively or not significantly associated with leptospirosis and plague. In China, the three diseases showed contrasting suitability patterns, with approximately 404 million people (29.3%) exposed to at least one high-suitability area.
CONCLUSIONS
Our analysis elucidates disease-specific ecological drivers and identifies spatial priorities to inform targeted One Health surveillance and integrated interventions.
Hongyan Wu, Kang Yu, Yurun Xue et al.· Journal of Infection· 0 citations