Published 20.19
The outbreak of bird flu killed 700 laughing gulls in the Kalmar area in the summer of 2023. But the birds that survived have developed long-term protection against the virus, a new study shows.
Researchers at Linnaeus University have followed the outbreak with the help of GPS-tagged laughing gulls, which provided an opportunity to study how the virus affected both the survival and behavior of wild birds.
“At each affected colony, you could see chicks with disease symptoms at the water’s edge, while dead chicks floated in the water. Adult birds showed neurological symptoms such as the inability to use their legs properly and convulsive head movements,” says Jonas Waldenström, professor of microbiology, in a press release.
The infected colonies exhibited altered behavior. The gulls moved significantly less during the breeding season than normal and began the autumn migration almost two weeks earlier than expected. According to the researchers, the infection is a likely cause.
After the outbreak, the researchers recaptured laughing gulls that survived the infection to analyze their immunity. A year after the outbreak, they had high levels of antibodies against the virus. Two years later, the proportion of protected birds had not decreased, even though antibody levels had decreased.
“The results indicate that laughing gulls that survive the infection can be protected against the virus for at least two years,” says PhD student Alessia Ostolani.
