Rabies is a deadly disease caused by a virus that usually spreads from an infected animal to a human through a bite. Early symptoms of rabies are rather vague and can take a while to develop. Once the disease progresses, though, it is nearly always fatal. According to the World Health Organization, tens of thousands of people worldwide die from rabies annually. It is important to know the signs and symptoms of this disease in animals and humans to avoid a worst-case scenario.

Transmission

The rabies virus spreads through direct contact. The most common mode of transmission is a bite, but there are rare cases when non-bite exposures can lead to the disease. Because saliva carries the virus, it is possible for people to get rabies through a scratch, wound, or abrasion licked by a rabid animal. Rabies is not spread through blood, feces, or urine.

Incubation Period

One of the most unpredictable things about rabies is the incubation period. The virus has to reach the brain before any symptoms develop. The typical incubation period is two to three months, but the effects of the disease can take as little as a week or as long as a year to appear. The severity and location of the bite, the strain of the virus, the innervation of the wound, and whether the person is treated after exposure all contribute to the length of the incubation period.

Early Symptoms of Infection

Early symptoms of rabies are vague and similar to those of the flu. They include fever, weakness, general discomfort, headache, vomiting, and nausea. The person may also experience itching, prickling, or general discomfort at the bite site. These symptoms can easily be written off as signs of other illnesses but should be taken very seriously if they develop after an animal bite.

Symptoms of Encephalitic vs. Paralytic Rabies

There are multiple strains of the rabies virus but only two variations in how the disease presents. Encephalitic, also called the “furious” form of rabies, is most common, hallmarked by aggression, excessive salivation, and agitation. This is the stereotypical presentation that comes to mind when thinking of rabies. Another less common presentation is paralytic or “dumb” rabies. Those infected with this second type are lethargic and experience muscle weakness and progressing paralysis. It is important to remember that the presentation does not change the severity of the disease. Encephalitic usually progresses faster, but paralytic is just as deadly.

Progression

The rabies virus is like a bullet, designed to make its way through the peripheral nervous system and into the brain. Once it gets to the brain, it replicates inside the nerve cells, destroying them in the process. After attacking the brain, the virus next travels to the salivary glands, which causes increased saliva production and foaming at the mouth.

Neurological Symptoms

The effect of rabies on the brain is devastating. Within days of the virus reaching the central nervous system, a person or animal infected with rabies experiences seizures, anxiety, confusion, delirium, aggression, and hallucinations plus difficulty walking, breathing, and swallowing. They may also experience hydrophobia. This part of the disease usually lasts between two and 10 days and results in death, in most cases.

Animals Who Transmit Rabies

Any mammal can transmit the rabies virus to another mammal. This includes pets, such as cats, dogs, and horses, and wild animals, like bats, raccoons, monkeys, skunks, and foxes. Observe pets and farm animals that bite but show no signs of rabies for 10 days to see if symptoms develop. Capture wild animals that bite someone, if possible, for testing. If someone is bitten by an animal they cannot find or one that has gotten away, it is often best to assume that the animal had rabies and proceed with treatment.

Prevention

One of the best things any pet owner can do to prevent rabies is get their animals vaccinated. When pets are outdoors, keep them confined to lower the risk of contact with a wild animal. Small pets, like rabbits and guinea pigs, cannot receive a rabies vaccination; keep them indoors or in cages to protect them from wild animal attacks. Report and avoid strays and wild animals that appear friendly. Finally, keep bats out of your home. Bats, whose bites do not hurt and often go unnoticed, are one of the most common carriers of rabies.

After a Bite

If you have been bitten, the first thing you should do is wash the wound with soap and water to try to wash away the virus. Capture the animal if possible but do not shoot it in the head, as technicians need brain tissue to confirm a rabies diagnosis. Go to the emergency room immediately. If you were able to capture the animal, the hospital will likely contact the health department. Anyone who has not received a rabies vaccination will receive human rabies immune globulin (HRIG), injected in the area of the wound, as an immediate response to the virus.

Outlook

Getting immediate treatment is important because it is the only chance to prevent the virus from establishing itself in the central nervous system. Once the virus spreads to the brain, the result is usually fatal. Very few people have survived an infection without vaccination.