The H5N2 bird flu that’s killed or forced the slaughter of 49 million birds and driven up the price of eggs is being spread by poor hygiene practices and might even be spread in windstorms, U.S. agriculture officials said Monday.
The new U.S. Department of Agriculture report doesn’t pinpoint the precise sources of spread, but says there’s enough evidence to show many different sources.
Scientists from the USDA’s Animal and Plant Health Inspection Service (APHIS) believe wild birds were responsible for introducing the flu to commercial poultry, but now think the virus is spreading “in other ways as well,” according to the report.
“For example, APHIS has observed the following: sharing of equipment between an infected and noninfected farm; employees moving between infected and noninfected farms; lack of cleaning and disinfection of vehicles moving between farms; and reports of rodents or small wild birds inside the poultry houses,” it says.
“APHIS found that air samples collected outside of infected poultry houses contain virus particles, indicating that the virus could be transmitted by air,” USDA says. “In addition, preliminary analysis of wind data shows a relationship between sustained high winds and an increase in the number of infected farms approximately five days later.”
Officials have previously told NBC News these methods of transmission were being studied. The outbreak has spread to 15 states, although USDA says there’s evidence the spread has slowed.
Highly pathogenic bird flu is common in Asia and Europe but it’s extremely unusual in the U.S. and this is by far the worst outbreak ever. It’s not only bad for poultry; H5N1 and H7N9 bird flu viruses have infected and killed people. The Centers for Disease Control and Prevention has warned U.S. hospitals and doctors to be on the lookout for people who may have been infected with H5N2.
H7N9 avian influenza has infected more than 620 people since 2013 and killed 227 of them. H5N1 has infected 784 people in 16 countries since 2003, and killed 429 of them.
