Pathogenicity of High Path Avian Influenza Varies from One Species to Another

Farmscape for June 4, 2024

The executive Director of the Swine Health Information Center says the pathogenicity of high path avian influenza varies dramatically from species to species.
In response to the identification of highly pathogenic avian influenza H5N1 in dairy cattle and goats in the U.S. in March, the Swine Health Information Center and American Association of Swine Veterinarians hosted a webinar to discuss the implications for pork.
SHIC Executive Director Dr. Megan Niederwerder says domestic poultry face the most extreme risk.

Quote-Dr. Megan Niederwerder-Swine Health Information Center:
When we see H5N1 in wild birds, often times that infection can be completely asymptomatic so those birds can appear healthy, they may not have any clinical signs.
Then when we see the H5N1 in domestic poultry, as the name suggests, we see a very high pathogenicity or high death loss, very severe infection of that H5N1 in domestic poultry.
Then, what we've seen with regards to the recent introduction into dairy cattle is that the symptoms are fairly mild in dairy cattle.
We see that the primary clinical signs that we notice and have been reported in dairy cattle primarily have to do with milk production.
What we'll see is that the cows may have decreased activity with a drop in rumination and a decline in feed intake but often times those dairy cattle are recovering from those infections fairly quickly, within 10 to 14 days.
So, the symptoms of infection from species to species can differ quite dramatically.

Dr. Niederwerder says, while there have been no incidents of pigs being infected by the virus, biosecurity measures that address the possible exposure of pigs to wild birds and wild scavengers remains important.
The Swine Health Information Center-American Association of Swine Veterinarians webinar can be accessed at
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Bruce Cochrane.

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