An international investigation concluded that the mass mortality of Adélie penguins and other seabirds, recorded in March 2024 on the Danger Islands, Antarctica, was caused by avian cholera, and not by the H5N1 avian influenza, as scientists initially suspected.
The team analyzed tissue samples and swabs collected from 49 carcasses and identified the bacterial disease as the cause of death for the majority of the animals examined. The finding suggests that avian cholera may be a more frequent cause of mortality among Antarctic wildlife than previously thought.
Genetic analyses also revealed that the bacterial strain responsible for the outbreak has circulated in Antarctica for more than two decades. This result indicates that the disease was already present in the region long before the mortality event observed in 2024.
The researchers underscore the importance of maintaining surveillance of diseases that affect birds and other wildlife in Antarctica, as well as of deepening the investigation into their transmission and impact on populations. Accurate identification of the agents responsible for mass mortality events is essential to understand biodiversity threats and to improve wildlife monitoring in a region that is particularly vulnerable.
