What you need to know about Rabies
cherrelRabies virus they belong to the family Rhabdoviridae, genus Lyssavirus and include 16 different officially recognized species, of which the prototype species is the rabies virus. It is a disease caused by a virus spread by wild animals such as raccoons, skunks and bats. Domestic animals, dogs, cats and horses can get rabies. It can also be spread to humans. If left untreated; rabies is fatal. This disease is fatal. Rabies is a vaccine-preventable viral disease which occurs in more than 150 countries and territories.
Characteristics of rabid animals:
Rabid animals may behave in ways that are abnormal behavior. They may appear tame and friendly or be very aggressive and attack humans. In addition, they may drool a lot and have difficulty walking and walking and moving. Finally, rabid animals eventually die.
What to do after a bite?
This process should be done immediately after exposure. After being bitten or potentially exposed to the exposed to the rabies virus, the wound should be washed thoroughly with soap and water for ten minutes, then seek medical attention immediately. A doctor will assess the risk and determine if preventive treatment is necessary. These treatments are very effective.
Rabies is present on all continents, except Antarctica, with over 95% of human deaths occurring in the Asia and Africa regions. Dogs are the main source of human rabies deaths, contributing up to 99% of all rabies transmissions to humans. Interrupting transmission is feasible through vaccination of dogs and prevention of dog bites. Infection causes tens of thousands of deaths every year, mainly in Asia and Africa. 40% of people bitten by suspect rabid animals are children under 15 years of age.
Every year, more than 29 million people worldwide receive a post-bite vaccination. This is estimated to prevent hundreds of thousands of rabies deaths annually.
Three epidemiological cycles can be distinguished:
- Street or canine rabies: stray dogs in developing countries;
- Sylvatic rabies or wild animal rabies: red fox in Europe, raccoon in the United States, mongoose in United States, mongoose in South Africa, skunk in the USA (Arizona), bear in Romania;
- Rabies in chiropterans: vampires in Central and South America (Brazil), bats insectivores and frugivores in the whole world, including Australia.
Worldwide, approximately 59,000 people die of rabies each year, which means that one person dies of rabies every 9 minutes. Africa bears a disproportionate burden of this disease: in sub-Saharan Africa alone, an estimated 21,000 people still die of rabies each year. (https://www.fao.org/africa/news/detail-news/en/c/1310256/)
Case definitions:
- Suspect case:
Any person with a rash and/or fever and at least one of the following signs or symptoms: Arthralgia; or Arthritis; or Conjunctivitis (non-purulent/hyperemic).
- Probable case:
Suspect case in which IgM antibodies to Zika virus are detected and an epidemiological link is established (without evidence of infection with other flaviviruses).
- Confirmed case:
Any person with recent laboratory-confirmed infection with Zika virus:
- Detection of Zika virus RNA or antigen in serum or other specimens (e.g. saliva, urine, tissue, whole blood); or
- Detection of IgM antibodies to Zika virus and PRNT90 for Zika virus with titre ≥20 and PRNT90 titer ratio for Zika virus ≥ 4 to other flaviviruses; and exclusion of other flaviviruses.
Transmission:
People are usually infected following a deep bite or scratch from an animal with rabies, and transmission to humans by rabid dogs accounts for up to 99% of cases.
In the Americas, bats are now the major source of human rabies deaths as dog-mediated transmission has mostly been broken in this region. Bat rabies is also an emerging public health threat in Australia and Western Europe. Human deaths following exposure to foxes, raccoons, skunks, jackals, mongooses and other wild carnivore host species are very rare, and bites from rodents are not known to transmit rabies.
Transmission can also occur if saliva of infected animals comes into direct contact with human mucosa or fresh skin wounds. Contraction of rabies through inhalation of virus-containing aerosols or through transplantation of infected organs is described, but extremely rare.
Human-to-human transmission is extremely rare. The transmission of rabies through transplants (cornea, liver, kidney…) is exceptional, but poses the problem of transplants from deceased donors in a neurological context with no real etiology: These are the only documented cases of human-to-human transmission. Human-to-human transmission through bites or saliva is theoretically possible but has never been confirmed. (http://medecinetropicale.free.fr/cours/rage.pdf)
Population at risk:
Rabies is one of the Neglected Tropical Diseases (NTD) that predominantly affects poor and vulnerable populations who live in remote rural locations. Approximately 80% of human cases occur in rural areas. Although effective human vaccines and immunoglobulins exist for rabies, they are not readily available or accessible to those in need. Globally, rabies deaths are rarely reported and children between the ages of 5–14 years are frequent victims.
Signs and Symptoms:
The incubation period for rabies is typically 2–3 months but may vary from 1 week to 1 year, dependent upon factors such as the location of virus entry and viral load. Initial symptoms of rabies include a fever with pain and unusual or unexplained tingling, pricking, or burning sensation (paraesthesia) at the wound site. The first symptoms of rabies include headache, fever, lethargy, and sometimes discomfort at the bite site. Within a few days, the disease progresses to paralysis, throat muscle spasms, convulsions, delirium and death.
As the virus spreads to the central nervous system, progressive and fatal inflammation of the brain and spinal cord develops.
There are two forms of the disease:
- Furious rabies results in 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 accounts for about 20% of the total number of human cases. This form of rabies 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.
Diagnosis:
Current diagnostic tools are not suitable for detecting rabies infection before the onset of clinical disease, and unless the rabies-specific signs of hydrophobia or aerophobia are present, clinical diagnosis may be difficult. 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)
Treatment and prophylaxis:
Post-exposure prophylaxis (PEP) is the immediate treatment of a bite victim after rabies exposure. This prevents virus entry into the central nervous system, which results in imminent death. PEP consists of:
- Extensive washing and local treatment of the bite wound or scratch as soon as possible after a suspected exposure;
- A course of potent and effective rabies vaccine that meets WHO standards; and
- The administration of rabies immunoglobulin (RIG), if indicated.
Starting the treatment soon after an exposure to rabies virus can effectively prevent the onset of symptoms and death.
Extensive wound washing
This first-aid measure includes immediate and thorough flushing and washing of the wound for a minimum of 15 minutes with soap and water, detergent, povidone iodine or other substances that remove and kill the rabies virus.
Prevention:
- Eliminating rabies in dogs
Rabies is a vaccine-preventable disease. Vaccinating dogs is the most cost-effective strategy for preventing rabies in people. Dog vaccination reduces deaths attributable to dog-mediated rabies and the need for PEP as a part of dog bite patient care.
- Awareness on rabies and preventing dog bites
Education on dog behaviour and bite prevention for both children and adults is an essential extension of a rabies vaccination programme and can decrease both the incidence of human rabies and the financial burden of treating dog bites. Increasing awareness of rabies prevention and control in communities includes education and information on responsible pet ownership, how to prevent dog bites, and immediate care measures after a bite. Engagement and ownership of the programme at the community level increases reach and uptake of key messages.
- Immunization of people
The same vaccine is used to immunize people after an exposure (see PEP) or before exposure to rabies (less common). Pre-exposure immunization is recommended for people in certain high-risk occupations such as laboratory workers handling live rabies and rabies-related (lyssavirus) viruses; and people (such as animal disease control staff and wildlife rangers) whose professional or personal activities might bring them into direct contact with bats, carnivores, or other mammals that may be infected.
Pre-exposure immunization might be indicated also for outdoor travellers to and expatriates living in remote areas with a high rabies exposure risk and limited local access to rabies biologics. Finally, immunization should also be considered for children living in, or visiting such areas. As they play with animals, they may receive more severe bites, or may not report bites.
Engagement of multiple sectors and One Health collaboration including community education, awareness programmes and vaccination campaigns are critical. WHO leads the collective “United Against Rabies” to drive progress towards « Zero human deaths from dog-mediated rabies by 2030 ». Rabies is included in WHO’s new 2021-2030 road map. As a zoonotic disease, it requires close cross-sectoral coordination at the national, regional and global levels. World Rabies Day is celebrated every September 28 and is one of the most important global awareness days. Globally rabies causes an estimated cost of US$ 8.6 billion per year.
