Emerging Infectious Diseases magazine reports on an infection and mortality event involving both birds and mammals at a UK wildlife rehabilitation center late last year. While in captivity, five swans were infected by the H5N8 virus, a highly pathogenic variety that causes bird flu and in this case made the jump to other animals. After the appearance of the outbreak, a fox and five seals died (or were euthanized), and after their death, the H5N8 virus was determined as the cause of the disease.
In seals, the disease manifested in the form of seizures, and immunohistochemical and molecular tests on post-mortem samples detected a neurological distribution of viral products. The fox died overnight after the sudden onset of inappetence, and postmortem tissues also revealed a neurological and respiratory distribution of viral products. Live virus was isolated from swans, seals, and foxes, and a single genetic change was detected as a possible adaptive mutation in the mammalian-derived viral sequences. No human flu-like illness was reported in the weeks following the event, the study authors note.
“Although genetic analyzes did not indicate an increased risk of human infection with H5N8 viruses in this outbreak, the research shows how these viruses may pose unexpected and serious health risks to mammalian species,” the authors wrote in their report. The findings “further highlight the importance of wildlife disease surveillance,” they conclude.
Reference: Floyd T, Banyard AC, Lean F, et al. Encephalitis and Death in Wild Mammals at a Rehabilitation Center after Infection with Highly Pathogenic Avian Influenza A (H5N8) Virus, United Kingdom. Emerging Infectious Diseases. 2021; 27 (11): 2856-2863. doi: 10.3201 / eid2711.211225.
