Any mammal can theoretically contract the rabies virus, but cases involving the North American opossum are statistically the lowest among common wildlife species. While the answer to whether an opossum can carry rabies is yes, it is extremely rare, making it an unlikely source of infection. Less than one percent of all reported rabies cases in the United States involve opossums, placing them at the bottom of the statistical risk list.
The Biological Reason for Low Risk
The primary factor contributing to the opossum’s low infection rate is its unique internal physiology, particularly its body temperature. Unlike most placental mammals, the Virginia opossum has a lower average core body temperature, typically ranging from 94 to 97 degrees Fahrenheit (34.4–36.1°C). This range is significantly cooler than the internal temperature of most other North American mammals.
The rabies virus, a type of lyssavirus, requires a higher optimal temperature to successfully replicate and thrive within a host’s central nervous system. The opossum’s naturally lower temperature creates a difficult environment for the virus to multiply effectively enough to cause a full-blown, transmissible infection.
This physiological resistance means that even if an opossum is bitten by a rabid animal, the virus frequently fails to complete its journey to the brain. It also fails to reach a concentration high enough to be shed in the saliva. Scientific surveillance consistently shows that opossums are not considered a major reservoir species for the virus.
Common Rabies Carriers and Transmission
To provide context for the low risk posed by opossums, it is important to recognize the actual primary carriers of rabies in North America. Wildlife accounts for over 90 percent of all reported animal rabies cases in the U.S., with a few species acting as main reservoir hosts. These include raccoons, skunks, foxes, and bats, which maintain distinct variants of the virus within their populations across different geographical regions.
Raccoons are frequently the most reported rabid wild animal in the United States, followed closely by bats and skunks. Bats, in particular, are responsible for the majority of human rabies deaths in the U.S. because their bites can be very small and sometimes go unnoticed. Understanding these common vectors helps the public focus their caution on the animals that pose the highest risk of transmission.
The transmission of rabies occurs when the virus-laden saliva of an infected mammal enters the body of another animal or human. This typically happens through a bite, where the virus is inoculated directly into the muscle tissue. Transmission can also occur if infectious saliva contacts an open wound or a mucous membrane, such as the eyes, nose, or mouth. Once the virus reaches the central nervous system and symptoms appear, the disease is nearly always fatal.
Safety Guidelines for Wildlife Encounters
Because rabies is a serious neurological disease, maintaining a safe distance from all wild animals is the best practice for prevention. Never attempt to approach, feed, or handle any wild mammal, even if it appears harmless or injured. Securing outdoor garbage cans and keeping pet food indoors eliminates attractants that draw wildlife, including reservoir species, closer to human residences.
If a pet has an encounter with a wild animal, ensure its rabies vaccination is current, as this protects the entire household. If a human is bitten or scratched by any wild or unfamiliar animal, the wound should be immediately washed thoroughly with soap and water for 10 to 15 minutes. Following this first aid, promptly contact a healthcare provider and local health authorities to determine the need for post-exposure prophylaxis.