On Mar. 15, 2023, the United Kingdom Animal and Plant Health Agency reported that the carcesses of Common dolphins and Harbour porpoises were discovered on beaches in East Riding of Yorkshir England, Devon, England and Pembrokeshire, Wesal that test positive for avian influenza (HPAI) A(H5N1) virus.

It is thought that these cases have been caused by the dolphins eating infected birds. There is very limited evidence of mammal-to-mammal transmission in the wild. Avian influenza primarily affects poultry and wild birds, but there are an increasing number of avian influenza cases in mammalian animals, including both terrestrial and aquatic.

Since 2021, the total number of confirmed cases in non-avian wildlife in the UK comes to 23. Previous cases have been confirmed in red foxes, grey seals, harbour seals and Eurasian otters, but these are the first confirmed cases in common dolphins. Avian flu has been found in dolphins in other parts of the world, including Florida and Peru.

APHA cannot confirm that avian influenza was the sole cause of death with these two dolphins, it is possible that there were other contributing factors. A spokesperson for APHA said: “Samples taken as part of routine wildlife surveillance have detected the presence of influenza of avian origin in two dolphins and one porpoise. “The animals were found dead, and it is very likely they had predated on infected wild birds.

“The presence of influenza of avian origin in mammals is not new, although it is uncommon, and the risk of the H5N1 strain to non-avian UK wildlife remains low.”