A type of flu that sickens chickens, turkeys and wild birds has spread to all states, hurting commercial farms and boosting egg prices. It's part of a global outbreak that began in 2022. Public health risks are low, experts say, though a few cases among U.S. dairy and poultry workers and veterinarians appeared recently. The influenza variety, known as the H5N1 virus, spreads from wild ducks, geese and swans to poultry, cattle and even cats. People can catch it from infected cows, but don't get seriously ill or spread it to other humans – so there's no threat of another pandemic.

Farms with infected hens have to destroy their entire flocks, which is why some stores have empty egg shelves and limit purchases to one carton per buyer. Contaminated eggs are unlikely to reach grocers, experts say. Federal regulations require that commercial eggs to be washed and sanitized, which helps remove virus particles from the outside of shells. In addition, sick birds usually die before laying tainted eggs. Plus, cooking kills any virus. Milk and other dairy products that have been pasteurized also are safe.

Since the virus emerged in this country three years ago, outbreaks have led to the loss of a record 159 million birds at poultry farms across all 50 states and Puerto Rico. It also has affected cattle in at least 16 states, though most recover quickly and few are lost. Poultry and cattle farm employees are encouraged to wear protective equipment and take other safeguards.

Professor says: "The more it circulates, the more animals it infects, the more people that are exposed. There's all these opportunities for there to be potential mutations and ultimately adaptations." -- Benjamin Anderson, University of Florida College of Public Health

State specialist says: "The best advice we can give is to avoid handling wild birds." -- Jasmine Batten, Wisconsin Department of Natural Resources wildlife supervisor

Federal agency says: "While the current public health risk is low, CDC is watching the situation carefully and working with states to monitor people with animal exposures." – Centers for Disease Control