Bird flu typically spreads among birds, but there have been recent outbreaks among cattle in the U.S., and one Texas man contracted the virus from sick cows. Here’s why so many experts are worried about a possible new pandemic.

Even as the H5N1 virus evolves, gaps remain in the nation’s contingency plans for human testing, scientists say.

According to CNN, “Genetic analysis of the virus from one of the recent human cases involved in the poultry culling was reassuring, Shah said, because it didn’t show any mutations that might indicate the virus is spreading more readily to people. Testing also showed that the virus was closely related to the strain spreading in cattle.”

Since May, a number of poultry farms around Australia have faced outbreaks of avian influenza, or bird flu. These outbreaks have been devastating for the poultry farms affected, necessitating large-scale culls,

Beholden to the profit interests of the poultry and dairy industries, federal and state agencies with the authority and technology to contain H5N1 and prevent it from becoming the next pandemic are not doing what is both within their means and required.

U.S. cases of bird flu have been relatively mild and limited to farm workers who handled sick animals – a sign the virus may not be well suited to infecting humans in its current state.

Bird flu appears to have spread from a Colorado dairy farm to a nearby poultry farm, infecting five human workers who had been tasked with culling the affected birds. The highly infectious virus, avian influenza H5N1,