Most wildlife diseases are caused by bacteria, viruses, fungi, or parasites. Those that can be transmitted to people are called “zoonotic diseases” or “zoonoses.” A person can become infected in a number of ways. Most often, this happens when an infected animal bites or scratches you, or you inhale or touch contaminated “hot spots” of disease. Disease agents may enter your body through wounds, or through your eyes, nose, or mouth.

You can also pick up diseases indirectly, when you’re bitten by a mosquito, tick, or flea that fed on an infected animal. Mosquitoes spread West Nile virus, ticks spread Lyme disease, and fleas carry plague and typhus.

Some diseases are transmitted through the air, such as hantavirus or histoplasmosis. You can inhale them, especially while stirring up dust in a confined space. Touching your mouth after you’ve touched something that’s contaminated, or eating infected meat that hasn’t been properly cooked may also cause an infection. This is a significant problem for young children, especially when they play outdoors. Their sandboxes, play areas, or toys may become contaminated by the droppings or urine of wildlife. Kids may put soil, wood chips, or droppings into their mouths. Raccoon roundworm is spread in this way if the parasite’s eggs are present in contaminated soil.