Two decades of avian influenza in cats: A systematic review
A systematic review published in Open Forum Infectious Diseases examines the epidemiology and distribution of avian influenza virus (AIV) infections in felines over the past two decades, from 2004 to 2024. Given the susceptibility of cats to AIV and their potential role as hosts for viral adaptation and cross-species transmission to humans, understanding the scope and dynamics of these infections is critical for public health and animal health surveillance.
The review identified a total of 607 AIV infections in felines, including 302 associated deaths, across 18 countries and 12 cat species. The majority of cases involved domestic cats, with a notable increase in reported infections occurring in 2023 and 2024, likely linked to the emergence of the H5N1 clade 2.3.4.4b. A total of 92.3% of feline cases were identified as highly pathogenic avian influenza (HPAI), and 7.7% were low-pathogenic avian flu. Among the PCR-positive infections, HPAI made up 99.7% of deaths. The review also highlighted that infections can be both subclinical and fatal, with cats preying on wild birds and mammals potentially serving as intermediaries for viral adaptation to mammals and possibly humans. Documented instances include feline-to-human transmission in Thailand and outbreaks in U.S. shelters, emphasizing the zoonotic and epidemiological significance of these cases.
