Roughly 53 million poultry have died as a result of the deadliest outbreak of bird flu in U.S. history, a virus scientists say is acting "like a kid in a candy store".

So far, avian influenza, or HPAI, has swept through 46 states, with the Midwest being hit the hardest. According to the Department of Agriculture, the 11 states spanning from Utah to Delaware each saw 1 million bird deaths. Iowa alone lost more than 5 million animals.

Unlike prior outbreaks, this virus is being spread by migratory wild birds rather than farm-to-farm transmission.

"We don't know exactly what it is about it, but it does seem just to be able to grow and transmit better in wild birds," the director of the World Health Organization's Collaborating Center for Studies on the Ecology of Influenza in Animals, Dr. Richard Webby, told NPR. "Wild birds are the perfect mechanism to spread a virus because they, of course, fly everywhere."

The Centers for Disease Control and Prevention (CDC) notes on its site that avian influenza has a mortality rate of "up to 90% to 100%", but "ducks can be infected without any signs of illness."

The majority of the deaths so far haven't actually been caused by the virus but were instead the result of culling efforts meant to prevent the illness from spreading. While Webby says it's possible that the birds could build up an immunity, the virus has been mutating rapidly.

"The bird populations haven't seen viruses like this before," Webby said, "so in terms of their immune response, they're all immunologically naïve to this."

With viruses so present in everyone's lives in the past few years, the first answer that comes to mind might be vaccines. However, due to the short life span of most birds, there isn't enough time to vaccinate the birds before they need to be ready for harvesting. Vaccines can also make it more difficult to identify infected chickens which may no longer show symptoms thanks to a stronger immune response.

In the meantime, the avian flu shouldn't have an impact on food safety. According to the CDC, regular cooking methods for eggs and chicken should kill any HPAI viruses that may be present. The only American that has reportedly been infected by this avian flu recovered after a few days of fatigue.

In addition, the illness has been more common among egg-laying poultry, not chickens raised for their meat.

"For whatever reason, turkeys and layer birds tend to be more susceptible" Amy Hagerman, an assistant professor at Oklahoma State University, told NPR. "The chicken that most people think of, their chicken tenders, their chicken sandwiches, all of those things haven't tended to have the same kinds of impact."

With that in mind, egg prices could soon be affected, and turkey prices were up during the holiday season. In fact, Hagerman says that egg and turkey producers are actually more vulnerable to price increases relative to other types of poultry products because their operations are typically smaller.

Usually, the heat of the summer can be relied upon to kill any viruses that crop up among the poultry population in the spring, but Hagerman said that didn't happen this year. The virus wasn't completely wiped out, and the cold of the winter months has led to a resurgence.

"If we look at Europe, we can see that they are on two years of HPAI outbreaks," Hagerman said.