Global strategies to control mammal-to-mammal avian flu transmission aren't working and pose an ongoing threat to people, especially as the viruses become entrenched in Europe and the Americas, according a team of virologists led by the United Kingdom's Pirbright Institute.
The scientists examined outbreaks in European fur farms, South American marine mammals, and US dairy cattle, noting the diversity of the species, along with changes in the ecology and molecular evolution of H5N1 in wild and domestic birds that increase the chances for spillover to a variety of mammals.
Their analysis comes as H5N1 outbreaks continue in US dairy cattle and as health officials in Missouri try to pin down the source of a recent human infection with no known animal or raw milk exposure and discern whether three other contacts with symptoms may have been infected with the same virus.
Tom Peacock, PhD, first author of the paper and a zoonotic flu specialist at Pirbright, said in a news release that influenza A viruses have triggered more pandemics than any other pathogen, and pigs have historically been considered the intermediary hosts. "However, the altered ecology of H5N1 has opened the door to new evolutionary pathways," he said.