Bird flu is spreading across
species—birds, cats, cows, and potentially humans. A new study warns that
without surveillance, we may be heading toward the next pandemic.
The
first major global review of bird flu in cats reveals an emerging threat of a
potential human pandemic.
Spring is here,
birds are on the move, and a new threat is spreading alongside them: bird flu
(H5N1). This virus is changing fast and
could be on the path to becoming a human pandemic. Scientists from the University of Maryland School of
Public Health have recently published a major study in Open Forum Infectious
Diseases highlighting a surprising new concern. They found
that cats are catching bird flu more often, and they’re calling for urgent
monitoring to help stop the virus before it can spread between people.
“The virus has evolved, and the way
that it jumps between species – from birds to cats,
and now between cows and cats, cats and humans – is very concerning. As summer
approaches, we are anticipating cases on farms and in the wild to rise again,”
says lead and senior author Dr. Kristen Coleman, assistant professor in UMD
School of Public Health’s Department of Global, Environmental and Occupational
Health and affiliate professor in UMD’s Department of Veterinary Medicine.
“Bird flu is very deadly to cats, and
we urgently need to figure out how widespread the virus is in cat populations
to better assess spillover risk to humans,” she said. “We want to help protect
both people and pets.”
Looking at data from 2004 to 2024,
researchers uncovered 607 cases of bird flu in cats around the world, including
302 deaths. These cases spanned 18 countries and involved 12 different types of
cats, from household pets to big cats like tigers. Despite the growing threat,
cats are not routinely tested for bird flu. In most cases, testing only happens
after the animal has died. Because of this limited surveillance, the real
number of infections is likely much higher, according to lead researcher Dr.
Kristen Coleman.
Increasing
Transmission Pathways
Yet the ways cats are getting bird flu are
multiplying. The study shows cats contract bird flu directly by eating infected
birds or contaminated raw chicken feed, and indirectly through other mammals –
for example, farm cats fed raw milk from infected cows, pet cats to other pet
cats, tigers to other tigers.
Infected cats often suffer from acute encephalitis
(brain swelling) and other severe symptoms, which are mistaken for rabies,
according to the study. The most deadly strain of bird flu is highly infectious
and makes up the majority of cases in domestic cats, with a current 90% case
fatality rate.
In humans, bird flu is slightly less deadly, but still has killed around half of the
950 people infected with it globally. Between April 28, 2022 (when
cumulative data on humans in the U.S. started being collected) and January 6,
2025, the United States has seen 66 confirmed cases in humans and one
death.
Human
Implications
Coleman and her
team are particularly concerned about the potential for bird flu getting into
animal shelters which could result in large outbreaks, potentially involving
humans – similar or worse to what happened in New York City with a different
strain of bird flu in 2016.
There are no reported cases of human-to-human
transmission of bird flu, but researchers are concerned that as the virus
spreads and evolves, it could become easily transmissible through the air.
“Our future research will involve studies to determine the prevalence of HPAI and other influenza viruses in high-risk cat populations such as dairy barn cats. Our research seeks to protect people and our vulnerable pet cats from the emerging threat of H5N1,” said Ian Gill Bemis, coauthor of the paper and doctoral student studying bird flu in cats.
No comments:
Post a Comment