Many of these detections have been seemingly one-off events that have not persisted,” Dr. “And despite being well over a year into this wildlife disease outbreak in North America, continued emphasis on research and surveillance to answer these sorts of questions is critically important.”Īlso unknown is just how virulent HPAI is to wild animals and if an infected animal can transmit the virus to offspring or other animals. “Spillover of HPAI from wild birds to mammals is not a simple process, with host, virus, and environmental factors at play,” she said. Behavior, diet, and previous exposure to influenza virus are among a complex set of factors to take into account. Wild mammals in which HPAI has been detected include many mesocarnivores that likely contracted the virus by eating HPAI-infected prey, Dr. Susceptibility to HPAI varies by mammalian species and even by individual animal, as is the case for wild birds, explained Rebecca Poulson, PhD, assistant research scientist with the Southeastern Cooperative Wildlife Disease Study at the University of Georgia College of Veterinary Medicine. The H5N1 virus subtype was detected in numerous species: bobcat, black and brown bears, bottlenose dolphin, harbor and grey seals, mountain lion, red fox, raccoon, striped skunk, and more. On March 29, the USDA first published its data on cases of HPAI infections in mammals from 2022 to late March 2023. Sporadic human cases of H5N1 reported with H5N1 viruses circulating in birds since 2021 have occurred following exposure to infected poultry. and globally, according to the Centers for Disease Control and Prevention (CDC).

No known human-to-human spread has occurred with the H5N1 virus that is currently circulating in birds in the U.S.

Influenza type A viruses include the highly pathogenic avian flu subtypes, such as H5N1, H7N9, and H9N2, as well as the swine flu subtypes H5N1 and H9N2. Of the four influenza virus types-A, B, C, and D-all can infect animals and type D is known to only infect humans.

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The spillover book