Rabies is a viral zoonotic disease that causes progressive and fatal inflammation of the brain and spinal cord. Clinically, it has two forms:
- Furious rabies – characterized by hyperactivity and hallucinations.
- Paralytic rabies – characterized by paralysis and coma.
Although fatal once clinical signs appear, rabies is entirely avoidable; vaccines, medicines and technologies have long been available to prevent death from rabies. Nevertheless, rabies still kills tens of thousands of people each year. Of these cases, approximately 99% are acquired from the bite of an infected dog.
Dog-mediated human rabies can be eliminated by tackling the disease at its source: infected dogs. Making people aware of how to avoid the bites of rabid dogs, to seek treatment when bitten and to vaccinate animals can successfully disrupt the rabies transmission cycle.
Rabies is estimated to cause 59 000 human deaths annually in over 150 countries, with 95% of cases occurring in Africa and Asia. Due to underreporting and uncertain estimates, this number is likely a gross underestimate. The burden of disease is disproportionally borne by rural poor populations, with approximately half of cases attributable to children under 15 years of age.
Symptoms
Early symptoms of a rabies infection can include a fever with pain and unusual or unexplained tingling, pricking or burning sensation (paraesthesia) at the wound site. In later states, the virus spreads to the central nervous system, causing fatal inflammation of the brain and spinal cord. The incubation period of the disease can vary from 1 week to 1 year, though it is typically 2–3 months.
The two types of rabies show different symptoms. Furious rabies causes signs of hyperactivity, excitable behaviour, hydrophobia (fear of water) and sometimes aerophobia (fear of drafts or of fresh air). Death occurs after a few days due to cardio-respiratory arrest.
Paralytic rabies, which accounts for about 20% of the total number of human cases, runs a less dramatic and usually longer course than the furious form. Muscles gradually become paralysed, starting at the site of the bite or scratch. A coma slowly develops and eventually death occurs. The paralytic form of rabies is often misdiagnosed, contributing to the under-reporting of the disease.
Treatment
The most cost-effective method to prevent rabies in humans is by vaccinating dogs. Pre-exposure immunization for humans also exists. In case of an animal bite, especially from a dog, it is important to immediately wash the wound with soap or detergent and flush it with water for 15 minutes. After washing and flushing, an iodine-containing or anti-viral medication can be applied to the wound. It is advised to avoid applying irritants or covering the wound with dressings. Seeking medical attention is important, and the biting animal should be safely confined and observed for 10 days. WHO advocates for rabies prevention through the eradication of rabies in dogs, implementing strategies to prevent dog bites, and using the intradermal route for post-exposure prophylaxis, which reduces vaccine volume and cost.
