While any mammal can contract rabies, the risk of an opossum carrying the virus is remarkably low. This article clarifies this common misconception by explaining the biological reasons and typical opossum behaviors.
Rabies Risk in Opossums
The primary reason opossums rarely contract rabies is their naturally lower body temperature, typically 94-97°F (34.4-36.1°C). This is several degrees cooler than most other mammals, and this cooler internal environment makes it difficult for the rabies virus to survive and replicate effectively.
Less than 1% of tested opossums are found to be rabies positive. Their lower body temperature often prevents the virus from completing its cycle and reaching the brain. Some research also suggests opossums have a robust immune system contributing to their resistance. These factors make them poor hosts for the rabies virus, significantly reducing their role in its transmission.
Understanding Possum Behavior
Opossums are primarily nocturnal, meaning they are most active at night while foraging for food. Seeing an opossum during the day does not automatically indicate illness; they may simply be searching for food or moving to a new den site.
When threatened, opossums often display defensive behaviors such as hissing, growling, and baring their teeth. They might also drool excessively, which is a stress response and not necessarily a sign of rabies.
Their most well-known defense mechanism is “playing possum,” an involuntary, catatonic state where they appear to be dead. During this state, they become limp, their breathing and heart rate decrease, their eyes may glaze over, and a foul-smelling fluid might be released from their anal glands, all to deter a predator.
Signs of a truly sick opossum, possibly with rabies or another illness, include disorientation, stumbling, paralysis, unusual aggression, non-stress-related excessive drooling, skin lesions, fur loss, labored breathing, or agitated behavior.
What to Do After a Possum Encounter
If you are bitten or scratched by an opossum, immediate action is important, even though the risk of rabies is low. Thoroughly wash the wound with soap and water for at least 15 minutes. Then, apply an antiseptic solution to the cleaned wound.
Seek prompt medical attention, especially if the bite is deep, bleeding persists, or if you notice signs of infection such as increased pain, swelling, redness, or discharge. Your doctor can assess the wound and determine if a tetanus booster or antibiotics are medically necessary.
If you encounter an opossum that appears sick or is behaving unusually, avoid approaching or attempting to handle the animal yourself. Instead, contact your local animal control, wildlife rehabilitation center, or health department. These professionals are equipped to safely assess and manage sick or injured wildlife. Observing opossums from a distance is typically the best course of action.