Rabies is a virus and is one of the most devastating diseases to affect mammals. Despite all of the resources of modern medicine, rabies is nearly always untreatable once symptoms begin, and it is important to take its threat seriously.
How is rabies transmitted?
The infection is transmitted when one infected animal bites another. In North America the skunk, fox, raccoon, and bat are the most important sources of infection.
How widespread is Rabies?
Every year the U.S. reports several human deaths, as well as hundreds of dog and cat deaths, from rabies. It is for this reason that most municipalities have licensing requirements to ensure that the community's dogs and cats are vaccinated against rabies.
What happens when an infected animal bites a person or another animal?
Virus in the infected animal's saliva enters the victim's tissues during a bite. The virus attaches to the local muscle cells for a few days before penetrating local nerves and beginning its slow ascent to the brain. Once in nervous tissue, the virus is not accessible to the body’s immune system and will proceed unchecked to the brain. This journey is slow, taking up to one year (the average time between bite and detectable virus in the brain is 20 to 30 days). The virus ultimately reaches the brain and two to three days later is evident in all body secretions, including saliva. At this point, the disease becomes transmissible and symptoms begin.
While it may take a long time for the virus to incubate, once even mild symptoms begin, death occurs within 10 days. There is no treatment for animals or humans once clinical signs appear.
Clinical signs progress through multiple stages (animals may sometimes skip either the excitative or the paralytic stage):
- Prodromal stage: (the first few days after symptoms have started)
A change in personality is noted. Friendly animals become shy, etc. The throat begins to spasm, and a voice change may be noted. Most infected animals will actively lick or scratch the site of the original bite.
- Excitative stage: (The next 2-3 days)
Classically, this would be the "mad dog" stage. The animal has no fear and suffers from hallucinations. If confined, the animal often attacks the bars of the cage. Dogs may display evidence of a depraved appetite, eating and chewing stones, earth, and rubbish. Hydrophobia (fear of water) is not a sign of rabies in dogs and cats. This is a feature of human rabies. - Paralytic or “dumb” stage (The next 2 days)
Weakness/paralysis sets in. The larynx is paralyzed resulting in an inability to swallow, thus drooling and "foaming at the mouth" result. It is from animals in this stage where most human exposure occurs. In this stage, owners will frequently think the animal has something stuck in the mouth or throat. Care should be taken in examination since rabies may be transmitted by saliva. Ultimately the animal becomes comatose and dies.
When human exposure to the animal in question is involved, what happens next depends on an assortment of criteria. If the animal in question is dead, its brain can be tested for rabies. There is no test for rabies in a living animal, but since we know that death follows quickly after the virus becomes contagious, a living animal can be confined for 10 days. If the animal is still alive 10 days after biting a person, then the bite could not have transmitted rabies.
Is it possible to survive a bite from a rabid animal?
There are isolated and poorly documented reports of both animals and people surviving. In some cases, there may have been very little rabies virus present in the saliva at the time the rabid animal bit its victim. In this situation, the victim may not develop rabies.
However, it is possible to interrupt the progression from an infected bite to the onset of signs by the early post-bite use of anti-rabies serum. This antiserum contains specific immune antibodies to the virus. The most important method for preventing the progression of rabies is by administering a dose of rabies vaccine. The vaccine stimulates the bitten person or animal to develop its own neutralizing antibodies to the rabies virus. Without vaccination and rapid post-exposure treatment, the chances of survival are poor.
What is the treatment for rabies?
There is no treatment for an animal with rabies. If rabies is suspected, the animal has to be kept in isolation and prevented from escaping or injuring someone. Your veterinarian is required by law to notify the local and state or provincial animal disease regulatory authorities. These authorities will determine the steps necessary to properly protect the public.
Can I catch rabies?
Yes, the disease can be transmitted from an animals to humans. It is only transmitted by the bite of a rabid animal. The virus is present in the saliva of the infected animal only for a limited time.
If any animal that may be suspicious for rabies bites you, immediately wash and flush the wound thoroughly with soap and water, and seek immediate medical assistance.
Post exposure rabies treatment with serum or vaccine may be recommended and is very successful if begun quickly.
Is it possible to vaccinate my dog or cat?There are several rabies vaccines approved for dogs and cats. The laws regarding rabies revaccination is dependent on state or provincial law. Your veterinarian will advise you on the appropriate revaccination intervals and can assist you in obtaining any necessary licenses for your pet.