Wildlife biologists say chronic wasting disease is spreading fast among deer in Iowa.The disease, also called zombie deer disease, infects the nervous systems of deer and elk, and is always fatal. The condition creates holes in an animal's brain, making its outward appearance like that of a zombie, and it's spread through deer-to-deer contact.No human cases have ever been recorded.The disease has been identified in at least 24 states, including Iowa, according to the Centers for Disease Control and Prevention. It's also been detected in Norway, Finland, Canada and South Korea."They lose all fear of humans," said Dale Garner, who leads the Iowa Department of Natural Resources Wildlife Bureau. "They're lethargic. They salivate."The first case of chronic wasting disease was discovered in Colorado in 1967. It then spread to Wisconsin, where thousands of deer have since contracted the illness.The fatal disease first appeared in a wild deer herd in Iowa in 2013. Since then, there have been 44 confirmed cases of chronic wasting disease, and 17 of those cases came in just the past year."It's a disease that you can't get rid of," Garner said. "There's no cure so far. As long as you have deer on the landscape and it continues to spread from animal to animal, you'll probably have more."RELATED: Here's what you need to know about the 'zombie’ deer disease Scientists worry that 'zombie deer disease' could infect humansIowa DNR officials advise against feeding wild deer and throwing carcasses in landfills, to prevent the spread of the disease. They also advise against eating any deer that has tested positive for the disease."Until we find a silver bullet, we just want to control the spread of the disease to the best of our ability," Garner said. "Hunting does that by eliminating some of those animals, and that's what controls populations."According the CDC, signs of an infected deer include drastic weight loss, drooling, lack of coordination and aggression.