The H5N1 Avian influenza, commonly known as bird flu, is causing significant impacts on bird populations globally. In the United States alone, over 136 million birds have been affected since the virus’s arrival in 2022. The disease has also shown potential to mutate and become more infectious to mammals, with cases reported in cats, zoo animals, people, and over 900 dairy herds.
David J. Cennimo, an associate professor of medicine and pediatrics at Rutgers New Jersey Medical School, shared insights about the disease with Rutgers Today. He explained that avian influenzas are viruses that spread easily among birds. The current strain of concern is H5N1 due to its possible human transmission risk. “This virus is similar to human-adapted influenza currently circulating (H1N1 and H3N2) but, to date, has not infected many humans or transmitted from human to human,” Cennimo noted.
Fewer than 100 human cases have been documented so far, mostly involving individuals who had close contact with sick birds. Recently, infections have increased in dairy herds with some secondary infections in humans from cows. Other mammals have also been infected. “In general, infections in other mammals are more concerning because…the virus could be adapting and becoming more infectious for humans,” Cennimo stated.
Infections typically occur through contact with sick animals or their droppings. However, there is no known risk from consuming cooked poultry or eggs as cooking eliminates the virus. There have been reports of sick cats believed to be infected by raw chicken pet food. While avian flu has been detected in milk from infected cows, pasteurization effectively neutralizes it.
The risk remains primarily for those working directly with sick animals or raw animal products. As seen with human influenza strains, individuals most susceptible to severe infection include those at extreme ages or with existing health conditions. “To date, we have not seen human-to-human transmission of avian influenza,” Cennimo emphasized.
Symptoms of infection mirror those of other influenza types: fever, cough, and upper respiratory issues. An increased occurrence of conjunctivitis has also been observed as a common symptom that may be confused with other viral infections.
Preventative measures include avoiding contact with sick birds or livestock and using personal protective equipment when necessary. Properly cooking food and pasteurizing milk can help reduce infection risks related to H5N1.
