Fatal as soon as symptoms appear

This disease is not well known, yet it is present around us. Both domestic and wild animals can carry the disease and infect people through saliva bites and scratches. More than 29 million people worldwide receive a post-bite vaccination. As soon as symptoms of rabies appears, it is always ends with death.

Rabies causes about 56 000 deaths worldwide per year. More than 95% of human deaths from rabies occur in Africa and Asia. About 40% of deaths occur in children under the age of 15. Rabies is present in more than 150 countries and on all continents but Antarctica.

What causes Rabies

Rabies is caused by rabies virus and lyssaviruses. It is spread when an infected animal deep bites or scratches a human or other animal. Saliva from an infected animal can also transmit rabies if the saliva comes into contact with the eyes, mouth, or nose. Though, 99% of the cases are mainly infected by dog’s bite, in America, bats are now the major source of human rabies deaths. Also in Australia and Western Europe, bat rabies is an emerging threat.

Other animals that can carry the disease are coyotes, foxes, raccoons and skunks. Cats can carry rabies but rarely infect humans.

Photo: cat and dog playing.

Where is Rabies found

Rabies is found in almost every country in the world, particularly in Central and South America, Africa and Asia. Bat rabies is an emerging threat in Australia and Western Europe. Rabies is estimated to cause 59 000 human deaths annually out of which 90% occur in Africa and Asia.

Approximately 80% of the human cases occur in rural areas of Asia and Africa. Most of the deaths reported are of the children between ages of 5 to 14 years. One of the reasons associated with the high number of deaths or affected in rural areas is the cost associated with managing rabies exposure. Treatment is costs on average US$ 108 and poses a substantial financial burden to the families leaving in a condition of hand-to-mouth incomes.

Image: Countries with rabies risk.

What are the symptoms of Rabies

When symptoms start to develop rabies is always fatal.

Initial symptoms of rabies include a fever with pain and unusual or unexplained tingling, pricking, or burning sensation (paraesthesia) at the wound site. Depending on the factors such as the location of virus entry and viral load, the incubation period may vary from two to three months. In some cases, it may take up to one year. Fatal inflammation of the brain and spinal cord develops as soon as the virus spreads and starts affecting the central nervous system.

Rabies affected may experience dizziness, fatigue, fever, loss of appetite, delirium, fear, hallucination, muscle spasms, sensitivity to light, anxiety, brain death, coma, difficulty swallowing, dilated pupils, drooling, headache, hypersalivation, mental confusion, seizure, or stiff neck.

Furious rabies results in signs of hyperactivity, excitable behavior, fear of water and sometimes fear of drafts or of fresh air followed by death in a few days due to cardio-respiratory arrest.

Paralytic rabies often misdiagnosed, contributing to the under-reporting of the disease, runs a less dramatic and usually longer course than the furious form. Muscles gradually become paralyzed, starting at the site of the bite or scratch. A coma slowly develops, and eventually death occurs.

In animals rabies causes aggressive behavior.

How can Rabies be prevented

Rabies is a vaccine-preventable disease and 100% preventable through prompt appropriate medical care, awareness and education. Vaccinating dogs is the most cost-effective strategy for preventing rabies in people. Vaccine can also be used to immunize people after an exposure or before exposure to rabies. Pre-exposure immunization is recommended for people in occupations which require handling or bringing them in direct contact with dogs, bats or other mammals that may be infected and carry rabies related viruses.

Pre-exposure immunization is also recommended to outdoor travelers and people living in remote areas with a high rabies exposure risk and limited local access to rabies biologics.

Besides vaccination, wound washing is lifesaving in case of a suspected contaminated scratch. Wash immediately with soap and water for at least 5 minutes.

Given how deadly this disease is, pets should always be vaccinated. Handling of stray animals should be avoided.

How is Rabies diagnosed

Rabies can be difficult to diagnose because, in the early stages, it is easily confused with other diseases or with aggressiveness. The differential diagnosis in a case of suspected human rabies may initially include any cause of encephalitis, in particular infection with viruses such as herpesviruses, enteroviruses, and arboviruses such as West Nile virus. The most important viruses to rule out are herpes simplex virus type one, varicella zoster virus, and (less commonly) enteroviruses, including coxsackieviruses, echoviruses, polioviruses, human enteroviruses 68 to 71 and Nipah virus.

In animals, rabies is diagnosed using the direct fluorescent antibody (DFA) test, which looks for the presence of rabies virus antigens in brain tissue. Human rabies can be confirmed intra-vitam and post mortem by various diagnostic techniques that detect whole viruses, viral antigens, or nucleic acids in infected tissues (brain, skin or saliva).

One of the most significant developments in recent years is the development and evaluation of a rapid immunohistochemical test called Direct Rapid Immunohistochemical Test (dRIT). The whole test procedure takes less than one hour and has the advantage of applicability under field conditions where fluorescence microscope is not available.

How is Rabies treated

Treatment after exposure can prevent the disease if given within 10 days. The rabies vaccine is 100% effective if given early, and still has a chance of success if delivery is delayed. It is recommended that people receive one dose of human rabies immunoglobulin (HRIG) and four doses of rabies vaccine over a 14-day period. As much as possible of the dose should be injected around the bites, with the remainder being given by deep intramuscular injection at a site distant from the vaccination site.

For symptomatic rabies, there is no treatment. Though a very small number of people have survived, the disease usually causes death.

If a person develops symptoms of viral encephalitis following an animal bite, they should be treated as if they may have rabies.

Edited by: Himanshu Arvind Kapadia

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