A genetic mutation in the H5N1 avian influenza virus — a mutation associated with increased infectivity and disease severity — has been discovered in two cats, and scientists have been found to say it is another indication of the risk posed by the virus.
“These are the most common microbiologist at Emory University in Atlanta,” said Sheema Rakdawala.
Henry Niman, founder of vaccine research firm Recombinomics Inc., reviewed the sequence data and reported the results to The Times.
The gene identified by Niman in sequencing data known as PB2 E627K is associated with increased mammal-to-mammal transmission in experimental animals and disease severity.
This is a mutation similar to that found, but has a slightly different origin. The cows have been infected with the B3.13 strain of H5N1, which has been widely circulating in dairy cows since March last year. The cat has been infected with the new strain of D1.1, which is spreading in wild birds, and is now also appearing in several cattle herds in Nevada and Arizona.
Niman said he believes the two cats are based in New Jersey and have been infected last month based on the scientific nomenclature used to label genetic sequences.
New Jersey Public Health and Raritan Township, which reported a cluster of infected cats in Hunterdon County last month, could not be immediately contacted for comment.
Since the beginning of 2025, the USDA has reported cats infected with 51 H5N1. They include both household pets and wild cats and have been found in 13 states since the beginning of the year, including California, Montana, Colorado, Oregon, Washington and New Jersey. Over 100 cases have been reported since the outbreak was first reported in dairy cows in March last year.
According to the report, all infected cats lived in the same property. . The living conditions of the remaining four cats are unknown.
On Thursday, a genetic sequence of the H5N1 virus, taken from two infected cats, was added to GISAID. This is a global initiative to share all your influenza data.
Richard Webbby, an infectious disease expert at St. Jude Hospital in Memphis, Tennessee, said the discovery of the mutation was not surprised in itself.
“This mutation has appeared sporadically in other mammalian infections over the past few years,” he said. “The H5 virus makes is a simple change and can be done relatively frequently.”
If it spreads more widely, he said it would be of concern.
There have been no reports of people infected in New Jersey, and state A said those who interacted with infected cats were asymptomatic.
According to that February 28 release, the infected cat said it did not report exposure to infected poultry, livestock, or raw (unpasteurized) milk or meat consumption, but “but it is unknown that it will be exposed to wild birds and other animals as they roam freely outdoors.”
Since the outbreak began in March last year.
