Best practices for nuisance wildlife control operators in New York State

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Ch 4: Section four: What you need to know about wildlife diseases

Rabies

Symptoms

An animal may be infected with rabies for a long time before it shows symptoms, anywhere from two weeks to many months. (The incubation period is usually two to three weeks.)

Different species show different signs of the disease. Expect variations even within the same species, because few animals show all of the signs of rabies. Some signs are subtle and easily missed.

Unfortunately, you can't tell whether or not an animal is rabid just by its behavior. Other diseases, such as distemper or toxoplasmosis, can also cause similar symptoms. An animal that's been poisoned by lead, mercury, or antifreeze may also act "rabid." The only way to prove that an animal is rabid is to test its brain tissue in a laboratory. That's why it's smart to take precautions.

Here are the rabies symptoms you may see in wild animals:

1. unprovoked aggression ("furious" rabies). Some animals may attack anything that moves, or even inanimate objects.
    
2. unusual friendliness ("dumb" rabies).
    
3. animal may stumble, fall, appear disoriented or uncoordinated, or wander aimlessly.
    
4. paralysis, often beginning in the hind legs or throat. Paralysis of the throat muscles can cause the animal to bark, whine, drool, choke, or froth at the mouth.
    
5. vocalizations ranging from chattering to shrill screams.
    
6. nocturnal animals may become unusually active during the day (remember, some daytime activity is normal, especially when nocturnal animals are feeding their young).
    
7. raccoons walk as if they're on very hot pavement.

Skunks, raccoons, foxes, and dogs usually display furious rabies. Bats often display dumb rabies, and may be found on the ground, unable to fly. This can be very risky for children, who are more likely to handle wild animals than adults. In domestic animals, rabies should be suspected if you see a sudden change in disposition, failure to eat or drink, or if the animal becomes paralyzed or runs into objects.

You may become aware of another similarity between rabies and distemper. Both are "density dependent" diseases. That means they spread more easily when wildlife populations are higher, because there's more contact between individual animals. When enough animals die from rabies or distemper, these viruses can't spread as easily. That's why the number of cases spikes and then drops off; this rollercoaster pattern repeats over time.

Next Section (Rabies: protection on the job)