The risk that a highly infectious strain of avian flu virus named H5N2 will infect humans is "low at this time," CDC officer Alicia Fry said during a press conference earlier today. The virus, which infects turkeys and chickens, is different from previous flu strains that have been able to infect humans, she said. So far, it has "not caused infections in humans anywhere in the world."

This virus has "not caused infections in humans anywhere in the world."

The H5N2 strain was first detected in the US in mid-December. So far, it has been detected in wild birds and commercial birds in 16 US states, including Arkansas, California, Kansas, Montana, Oregon, Utah, Washington, and Wisconsin. Commercial birds like chickens and turkeys were most likely infected via wild birds — namely geese, guinea fowl, and ducks. As a result, the USDA is reviewing biosecurity protocols in these areas to try to keep the virus out of commercial flocks.

Meanwhile, the CDC has been studying the virus to find out more about how it works. "So far, genetic analysis has not shown any of the markers that are known to be associated with increased severity in people or an increased ability to spread among people," Fry says. Still, the CDC is taking routine precautions that include trying to develop a vaccine that could be used in humans, should it ever be needed. "While we are cautiously optimistic that there will not be human cases, we must be prepared for that possibility," Fry says.

The CDC is developing a human vaccine, just in case

Despite the fact that the H5N2 flu virus hasn't infected humans, the CDC warns that people should try to avoid wild birds. They should also avoid domestic chickens and turkeys that show signs of illness. "Most human infections with avian influenza viruses have occurred with people in direct and prolonged contact with infected birds," Fry says. Birds that are sick stop eating and drinking. Within a few hours, they become extremely lethargic — a symptom that's followed rapidly by death. The flu can kill an entire flock within 48 hours; in Minnesota, measures used to prevent the flu's spread have cost turkey farmers over 1.6 million birds.