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Rabies

Overview

Rabies is a serious disease caused by a deadly virus. The virus is transmitted to human beings after being bitten by an infected animal. It is present in the saliva of infected animals, including stray dogs, cats, rabbits, bats, raccoons, skunks, foxes, and coyotes. This disease can manifest itself with serious symptoms, the primary concern of which is neurological issues. If the disease continues to progress, it is most likely fatal. Due to the advent of the rabies vaccine for both humans and animals, the incidence of rabies has decreased in the United States. 

Causes

Rabies is spread by the rabies virus. This virus belongs to the Rhabdoviridae family. Once it infects animals, it is present in their saliva. Getting bitten by an infected animal is the most common mode of transference of the rabies virus. In the United States, the animals involved in spreading the rabies virus are usually wild animals such as bats, raccoons, foxes, coyotes, etc. Stray dogs are a leading cause of spreading rabies in underdeveloped countries. 

Risk Factors And Epidemiology

The risk of rabies is higher for those who frequently travel to different parts of the world. Traveling to regions with active cases of rabies or where the risk of rabies is high can be dangerous. People who like to explore the habitat of wild animals or caves with bats are also at a higher risk. Camping at a risky site without proper precautionary measures can put you in danger of being attacked by an infected animal. Veterinarians or research scientists that work closely with infected animals are also at high risk. The fatality risk is much higher if you get wounded near the head and neck area because the virus can easily spread to the brain. 

 

According to World Health Organization (WHO), rabies has been reported across 150 countries worldwide. The United States has a lower incidence of rabies, with almost 2 to 3 cases reported every year. Vaccination of both humans and dogs has decreased the number of cases considerably. 

Signs And Symptoms

The signs and symptoms of rabies usually progress in stages. The first stage is the incubation period which is the duration before the symptoms appear. It can last from a few weeks to a year. Vaccination during this period can prevent the disease from spreading to the brain. If the symptoms begin to appear, that stage is called prodrome. Flu-like symptoms develop in the initial period, including fever, headache, generalized discomfort, sore throat, nausea/vomiting, etc. After this stage, the disease enters into an acute neurological period. You may develop confusion, aggression, partial paralysis, neck rigidity, muscle twitching, convulsions, hypersalivation, and severe breathing issues. It is nearly impossible to revert from this stage. This stage progresses towards coma and eventual death. 

Diagnosis

If a rabid animal has bitten you, there is no way to tell whether you carry the virus or not until your symptoms start to develop. After the onset of symptoms, the rabies virus can be detected in blood, saliva, or tissue samples. One of the tissue tests is the direct fluorescent antibody (DFA) test. These tests can only be helpful after the incubation period is over, and the virus becomes activated. In majority of the cases, the presence of history with an infected animal and appearance of symptoms is enough for diagnosis of rabies. 

Differential Diagnosis

Rabies needs to be differentiated from other diseases that can cause neurological symptoms. Examples include encephalitis, meningitis, poliomyelitis, neurosyphilis, herpes simplex virus infection, etc. It should be done quickly before the symptoms of rabies progress. 

Treatment

Rabies is a highly fatal disease. There has been no cure developed for rabies yet. However, if you get bitten by a suspected animal, you should immediately get vaccination shots to prevent the disease as much as possible. Rabies immunoglobulin is injected into your body, providing antibodies to fight the rabies virus. If you have already been vaccinated for rabies, you’ll still have to receive two shots over the first three days after being bitten. If you have not been vaccinated earlier, you’ll receive four shots over the period of 14 days. In case the animal that bit you can be caught, that animal is kept under observation as well to confirm whether it has rabies or not. If not possible, it is safest to assume that the animal had rabies and proceed with vaccination shots.

Medications

 

There are no medications available for the treatment of rabies. Only early vaccination or post-exposure prophylaxis (PEP) can give you a chance to prevent the development of full-blown disease. 

Prognosis

Those who receive PEP within the first ten days after being bitten by an animal have a high chance of preventing the development of rabies. If PEP is delayed or not given, the risk of fatality increases. The appearance of neurological symptoms shows that the disease has progressed out of control and will lead to death eventually. 

Prevention

Rabies is a deadly but preventable disease. If you are a frequent traveler, consider getting a rabies vaccination before traveling to areas with a risk of rabies. Veterinarians, research scientists, and others who have to work or monitor animals should also get vaccinated. Ensure to vaccinate your pets against rabies or check that they were vaccinated when you got them. Do not adopt a stray animal without following necessary preventive measures. Also, make sure to keep your pets within a safe living space and do not allow them to mingle with wild animals that may be possible carriers of the disease.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 27, 2023.

 

References

Rabies | CDC

https://www.cdc.gov/rabies/index.html

Rabies (who.int)

https://www.who.int/news-room/fact-sheets/detail/rabies

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