Researchers at Cummings School of Veterinary Medicine at Tufts University (US), in a study published on March 15 in Emerging Infectious Disease, associated a deadly 2022 outbreak of H5N1 with the deaths of New England harbor and gray seals in June and July 2022 along the US’s New England coast. The outbreak was connected to “a wave of avian influenza in birds in the region,” according to a March 15, 2023 report in Science Daily. Here is some of the report’s data on the disturbing toll of H5N1, a strain of highly pathogenic avian influenzaH (HPAI), known commonly as bird flu.
The deadly H5N1 has led to the destruction of 60 million US farmed birds since October 2020.
The Tufts study is among those to first connect HPAI directly to a deadly event in wild animal populations.
H5N1 recently killed many sea birds in Peru—notably 60,000 pelicans, penguins, and gulls.
Peru has also reported the deaths of 3,500 sea lions from the virus.
The Tufts research team identified at least three strains of bird flu that crossed the Atlantic to the US from Europe.
The deadly seal event in New England—330 animals perished—coincided with the deaths of gulls in the region.
H5N1 is almost 100% fatal for domestic and wild birds (except waterfowl). The same lethality held true for all the New England seals that tested positive, though it is unknown if some survivors in the seal population were asymptomatic.
Fewer than 10 human cases* of H5N1 have been reported globally since December 2021—all were associated with direct human exposure to infected poultry.
A total of 868 cases of human infection with H5N1 have been reported worldwide since 2003, according to the World Health Organization. Some 457 of these infections were fatal—about a 50% mortality rate.
*According to the Science Daily report, no documentation exists for human transmission of H5N1.