I was on Inside Edition last week to talk about zombies.

That’s a weird sentence to type.

While the story was dramatic, television clips are notoriously difficult to discuss anything of real significance. I had two main messages I wanted to get across. One, that we can’t be sure what these animals are suffering from just by appearance (this message kind of got missed in the clips they chose) and because of that, message two: you shouldn’t approach a potentially diseased animal yourself, but instead call animal control or your local wildlife professionals to come help (at least they did include me saying not to approach these animals).

In all likelihood, most of the animals they showed and that have been recently been “terrorizing” individuals in Youngstown, Ohio are suffering from infection with Canine Distemper Virus. This is a virus related to human measles, and like measles, is very contagious. From the name, it obviously affects dogs, but isn’t limited to only dogs. It can also infect raccoons, foxes, opossums, ferrets, and even wild tigers. Among animals, the distemper virus can be transmitted by bites or simple close contact, so it can spread quickly within groups of animals living together. The infected animals then either recover and develop immunity, or pass away from the infection.

The animals exhibiting “zombie” symptoms like those shown in the clip are just the tip of the iceberg. It’s likely that many other animals in the local population are also ill, but perhaps not dramatically so; like any infectious disease, there will be a spectrum of symptoms in infected individuals, so not every wild animal infected with Canine Distemper will “go zombie.”

Wildlife authorities have noted that these outbreaks of animals acting like “zombies” happen every few years: the virus will sweep through a population lacking herd immunity, infect many of the individuals, and those who are infected but recover will be immune. A few years later, when the population again contains large numbers of susceptible individuals due to births of new animals, the virus can again cause an outbreak—and the cycle continues over and over.

While canine distemper infection doesn’t cause symptoms in humans, rabies absolutely does—and that’s a key reason people need to avoid these animals and leave them to the professionals. Based on the symptoms alone, you can’t tell if an aggressive, strangely-behaving animal is suffering from distemper or rabies. And while distemper isn’t harmful to humans (though it definitely could be to your dog if they’re not up-to-date on their vaccinations), rabies is almost 100% fatal if not quickly treated with anti-rabies immunoglobulin and prophylactic vaccination. In the rare cases who have survived after symptoms developed, it was only with extreme interventions which are not always able to be replicated.

Expect to see these epidemics of “zombie animals” on a regular basis in different locations around the country—but don’t try to be a hero. That never turns out well in the movies.