The mention of the word rabies brings mental images of a fierce, aggressive dog frothing in its mouth ready to go for the kill. Rabies is a viral infection that spreads among people from the saliva of animals. Not just dogs, but animals like bats, foxes, coyotes, skunks, and raccoons also transmit the virus in the United States. Animals infected with rabies transmit the virus by biting or scratching humans.
By the time the signs and symptoms of rabies start to show, it is too late to save the person. The best way to prevent the disease is to get vaccinated against it. In the United States, between 1 and 3 people are infected by rabies annually. Several medical advancements, awareness and vaccination drives have reduced the incidence of the disease significantly. Effective treatment of the disease is possible only before the symptoms appear.
Symptoms of rabies
By the time the symptoms of rabies appear, it may have progressed to a fatal condition. Rabies affects humans in two ways:
- Entering the peripheral nervous system (PNS) and progressing to the brain
- Enters the muscle tissue and from here it enters the nervous system via neuromuscular junctions
Once the virus invades the nervous system, it causes inflammation of the brain. This inflammation results in coma and eventually, death. There are two types of the disease: paralytic or dumb rabies, in which the main symptom is paralysis; and furious or encephalitic rabies, in which the main symptoms are hyperactivity and hydrophobia.
Symptoms of rabies are classified into different stages described below:
- Incubation stage: At this stage, there will be no symptoms. This phase lasts up to 12 weeks. The effect of the bite is more pronounced if the bite is closer to the brain.
- Prodrome stage: People experience flu-like symptoms like fever, headache, anxiety, sore throat, cold, nausea, vomiting, and a general feeling of being unwell.
- Acute neurologic period: Neurologic symptoms like convulsions, partial paralysis, hyperventilation, hypersalivation, priapism, photophobia, nightmares, and hallucinations are experienced. At the end of this stage, breathing becomes rapid and inconsistent.
- Coma and death: At this stage, the person enters into a coma, and death happens within a few hours if they are not kept on ventilator. Recovery at this stage is not possible.
Causes of rabies
Rabies is a viral infection spread by the rhabdovirus family. Infected animals can spread the virus by biting another animal or a human. In very rare incidences, it may spread when the infected saliva comes in contact with an open wound or mucous membranes. Pet and farm animals like cats, dogs, cows, goats, horses, and ferrets can spread the virus. Wild animals like bats, beavers, monkeys, raccoons, skunks, woodchucks, and foxes can also spread it.
Rabies remains a major issue at the global level with tens of thousands of deaths resulting from the disease every year. Most rural areas of South Asia and Africa are affected by this disease. In these areas, rabies is caused by stray dogs. Without early treatment, rabies is a fatal disease.