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Rabies In Humans: Causes, Symptoms, Risk Factors, Treatment And Prevention

Rabies is a preventable yet common viral disease caused due to Rabies lyssavirus. It gets inside the human body through an animal bite. The disease has made its presence in more than 150 countries around the world. Normally, rabies occurs in warm-blooded mammals like dogs, bats, foxes, raccoons, cats, jackals and mongoose.

The virus then gets secreted in a larger amount in the saliva of the infected animal and gets transferred to humans through a bite or saliva exposure. Rabies is more common in remote rural areas where people reside near vulnerable animals [1] .

According to the WHO, rabies accounts for around 59000 deaths across the globe every year. India alone makes up for 36% of deaths worldwide caused due to rabies per year. The spread depends on the area where the maximum number of rabid mammals are found.

Among other animal-based diseases, rabies is the neglected one but people should be aware of the fact that if the condition remains untreated for long, it may cause coma or death of a person.

World Rabies Day 2019: Date, History, Theme And Significance

Causes Of Rabies In Humans

Rabies virus from rabid animals gets transmitted to humans through a bite, saliva exposure to open wounds and contact of infected saliva with the mucous membrane like eyes, mouth and nose. The infection also spreads when a rabid animal licks the open wound of humans [2] .

When a rabid animal bites, the virus enters a human body, travels to the brain and the spinal cord through nerves and starts causing symptoms. This takes 20-60 days after the bite [3] .

In Africa, stray dogs are the main cause of rabies in humans while in the US, raccoons, bats, coyotes, skunks, and foxes spread the disease.

Symptoms Of Rabies In Humans

There are two forms of rabies and accordingly, the symptoms are observed in humans. Common symptoms of rabies include the following [3] :

  • Pain
  • Fever [4]
  • tingling and burning sensation in the bitten area
  • Anxiety [5]
  • Headache
  • Sore throat [2]
  • Nausea
  • Cough
  • Vomiting [6]

Once the virus affects the central nervous system, it causes inflammation and damage to the brain. The symptoms of rabies according to their types are as follows:

1. Furious rabies: This occurs in 80% of people. When furious rabies occurs, people start getting symptoms like the following:

  • Hydrophobia, fear of water [7]
  • Confusion
  • Severe abdominal pain [6]
  • Aggressive behaviour [8]
  • Difficulty in swallowing [4]
  • Excess saliva production [9]
  • Hallucinations
  • Nightmares
  • Photophobia, fear of light [10]

2. Paralytic rabies: This occurs in around 20% of people and recognized by the following symptoms [11] :

  • Paralysis
  • Coma
  • Death

Risk Factors Of Rabies In Humans

  • Residing in a bat populated area [12] .
  • Camping in areas where most of the wild animals are found.
  • Staying in rural remote areas where wildlife exposure is more and access to vaccines is low.
  • Travelling to continents where rabies is endemic [13] .
  • Being under age 15.

Note: Rabies is not contagious. In rare cases, the virus gets transmitted through an organ transplant.

Diagnosis Of Rabies In Humans

The symptoms of rabies usually take 2 months to show after a bite. Therefore, there are no tests made available to date to diagnose the symptoms before its onset. Hence, whenever a person gets bitten by a rabid animal, medical experts don't wait for symptoms to come and start vaccinating the person [14] .

In case when the bitten animal is dead, tissue samples from their brain is collected to identify the infection.

Treatment Of Rabies In Humans

A rabid-infected person should seek immediate medical attention because once the symptoms are developed, it becomes critical to stop the spread of the virus and save the person. The treatment includes a series of 2 vaccination shots of rabies which are as follows:

  • Wound Cleaning: This involves cleaning of the wounds by ethanol or iodine aqueous solution.
  • Human rabies immunoglobulin (HRIG): It is a fast-acting shot of vaccine given shortly after an animal bite. HRIG contains immune antibodies that provide our body with immunity it requires to fight against the rabies virus. The vaccine is used as a passive immunization and injected into the bitten area as the first dose of the vaccine [15] .
  • Active immunization: This includes 4 or 5 doses of vaccine administered in a patient on 0, 3, 7, 14 and 28 days. The vaccine is injected mainly on arms. The multiple shots of the vaccine cause side effects like stomach pain, nausea, swelling, muscle ache and dizziness [16] .

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Prevention Of Rabies

  • Keep your pets vaccinated.
  • Before travelling abroad, do take pre-exposure vaccinations of rabies [13] .
  • If there are many stray animals in your area, report to animal control to check their numbers and prevention methods.
  • Prevent bats from nesting or entering into the areas of your home [12] .
  • Don't let your pets come in contact with wild animals.
  • Don't approach wild animals intentionally and stay at a safe distance from them.
  • Don't bring wild animals at home.
  • Teach your child about rabies and animals that are responsible for the spread.
View Article References
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  2. [2] Rupprecht CE. Rhabdoviruses: Rabies Virus. In: Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996.
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