Rabid animals behave abnormally, and since rabies cannot be confirmed without laboratory tests, strange behavior is often the only way to identify potential rabies exposure. Rabies causes animals to foam at the mouth or drool excessively. This is a common way to identify an animal that may be infected. Other signs of rabies include chewing at old wounds, trouble eating or swallowing and difficulty walking.
Abnormal behavior is the first clue of a rabid animal. Nocturnal animals may be seen during the day. Wild animals may act tame and allow humans to get much closer to them than normal. Domestic animals may seem aggressive or mean.
A definitive rabies diagnosis requires samples to be sent to a lab for testing. Brain tissue is required, so the animal must be euthanized prior to testing. Two samples are needed, preferably one from the brain stem and one from the cerebellum. The samples are analyzed for the rabies virus.
Another way to identify rabies in animals is to rule out the disease. This prevents the unnecessary euthanizing of an uninfected animal. A quarantine period of 10 days is usually sufficient to rule out rabies. If symptoms appear or worsen during that time, lab testing of the animal's brain is required.