The US is home to several types of squirrels. Because they don’t usually attack or bite us, squirrels and humans generally coexist peacefully. There are, however, a few diseases that squirrels are unfortunately susceptible to which they can spread to humans.
This disease caused by the bacterium Leptospira is common in many wildlife species including squirrels. In humans, symptoms of Leptospirosis include headaches, fever, weakness, rash and an array of symptoms that are often mistaken for other conditions. Severe cases of Leptospirosis can cause kidney damage and liver failure and could be life-threatening.
We generally associate Lyme disease with ticks, but since squirrels often host ticks, they can contract the disease and spread it to humans as well. If Lyme disease is left untreated, it can cause an inflammatory disorder which affects the nervous system, joints, and heart.
It is rare to contract this viral disease in the US because of our awareness and preventative measures for it. However, a squirrel infected with rabies can pass it on to a human through biting or scratching. A rabid squirrel or other forms of wildlife in the late stages of the disease will act in a strange manner. It may be aggressive and hyper, or lethargic and not alert, or it could be unable to walk and move around normally. This virus attacks the nervous system. It starts at the point of the bite and travels to the brain where it rapidly multiplies and spreads through the body. Once symptoms appear, the disease is fatal.
Salmonella is a bacteria that can be found in the droppings of most all wildlife species including squirrels. Salmonellosis can lead to symptoms similar to food poisoning such as stomach cramps, diarrhea, nausea, and vomiting.
Tularemia is caused by the bacterium called Francisella tularensis. It can be spread to humans through the bite of an infected squirrel or through physical contact with a living or dead infected squirrel or contaminated food, water, or droppings. The bacterium spreads easily and can enter the undamaged skin. The bacteria grows in the blood and causes a high fever. It can be a deadly disease if left untreated.
In order to avoid contracting a disease from a squirrel, refrain from coming in contact with wildlife, especially animals that seem sick.