29 April 2026
A recent study published in Emerging Infectious Diseases details a devastating mass mortality event among Eurasian cranes (Grus grus) during the autumn of 2025. The outbreak, caused by the highly pathogenic avian influenza (HPAI) A(H5N1) virus, represents a significant blow to the Western European migrating subpopulation, with an estimated 10% of the flyway population perishing within months.
The mortality event began in early October 2025 at Lake Galenbeck in Germany. Germany: Reported 18,164 deceased cranes between October and December 2025. France: Estimated fatalities reached between 15,000 and 20,000 birds. Spain: Reported an estimated 1,000 to 1,500 deaths, primarily around the Gallocanta lagoon. By early November, mortality rates in Germany began to subside as the surviving birds continued their migration south. The HPAI strain responsible was identified as clade 2.3.4.4b, genotype EA-2024-DI.2.1. The study highlights that the cranes' gregarious behavior at feeding and resting sites facilitated rapid viral spread. Night roosts in shallow, communal waters were identified as critical transmission points, where even minimal environmental viral loads in the water could infect susceptible birds. Phylogenetic analysis suggests that once the virus entered the population, the cranes acted as efficient amplifiers, driving the spread along their migratory route.
Günther et al. (2026) EID Volume 32, Number 5 - May 2026.
