Limited Detection of Influenza A Antibodies in Sandhill Cranes (Antigone canadensis) Wintering in the California Central Valley, USA

The emergence of clade 2.3.4.4b highly pathogenic H5N1 has led to unprecedented mortality events in crane populations globally. Despite increasing concern, little is known about the prevalence of influenza A virus (IAV) and resulting antibodies in Sandhill Cranes (Antigone canadensis). To address this knowledge gap, we sampled 31 Greater and two Lesser Sandhill Cranes (Antigone canadensis tabida and Antigone canadensis canadensis, respectively) wintering in California’s Central Valley during the 2023–2024 and 2024–2025 seasons to assess active infection with IAV. None of the sampled individuals tested positive for infection with IAV via rRT-qPCR. We also sampled 29 Greater and two Lesser Sandhill Cranes for serological evidence of prior exposure to IAV; four Greater Sandhill Cranes tested positive for IAV antibodies via bELISA and antibodies specific to H5 were detected in two individuals. These findings suggest prior exposure, potentially on breeding grounds where crane mortalities related to highly pathogenic H5 have been documented. However, the low seroprevalence observed in this study suggests that the Staten Island, California, wintering population may remain largely vulnerable to future outbreaks, though small sample size does limit the broader applicability of these findings.