Rabies is a deadly but vaccine preventable viral disease of mammals. It is mostly transmitted from rabid animal’s saliva that enters the body through a bite or broken skin. If untreated urgently, rabies can lead to coma and death. Rabies causes acute inflammation of the brain in warm-blooded animals. The disease can be transmitted from infected dogs to humans of all age groups. Human rabies is almost invariably fatal if post exposure prophylaxis is not administered prior to the onset of severe symptoms. The rabies virus infects the central nervous system, ultimately causing disease in the brain. Rabies may also inflame the spinal cord, producing transverse myelitis. In many cases, the infected animal is exceptionally aggressive, may attack unprovoked and exhibits uncharacteristic behaviour. Rabies is an example of viral pathogen modifying the behaviour of its host to facilitate its transmission to other hosts. After infection through bite, the virus travels fast along the neural pathways into the central nervous system and other organs.
The incubation period of the disease is usually a few months in humans. This depends on the distance the virus must travel to reach the central nervous system. Once the virus reaches the central nervous system and symptoms begin to show, the infection is virtually untreatable and fatal within days. The rabies virus travels to the brain by following the peripheral nerves. Also the salivary glands of the rabid animal harbour high concentrations of the virus, thus promoting further transmission.
WHAT IS RABIES
Rabies is an acute viral infection that affects the central nervous system of all warm-blooded animals. It is principally transmitted to man through bites from infected dogs. Rabies symptoms appear after an incubation period of 10 days to over a year and death occurs in about 5 days of infection. It is a vaccine preventable viral disease. Often mammals get it from rabid animal’s saliva that enters the body through a bite or wound. The virus travels from the entry port to the brain where it causes virulent swelling or inflammation. The inflammation provokes the symptoms of the disease with final result of death especially in children.
Infected animals can spread the virus by biting another animal or human. In rare cases, rabies can be spread when infected saliva gets into the mucous membranes such as the mouth or eyes. Rabies infection is possible if an infected animal licks open wound or cut on the skin including the anus.
INCIDENCES OF RABIES
Though rabies is a vaccine-preventable disease, it still poses a significant public health problem in many countries. Its potential to cause human deaths is irrespective of the available safe and effective vaccines for both human and veterinary use. Globally rabies causes about 55,000 human deaths (95% in Asia and Africa) annually. Roughly 97% of human rabies cases result from dog bites. Deaths result within 2 to 10 days after first symptoms. Once a patient becomes symptomatic, survival is rare and mortality is over 99%, even with the administration of proper and intensive care.
Rabies is a neglected disease of poor and vulnerable populations whose deaths are rarely reported. It occurs mainly in remote rural communities where measures to prevent dog to human transmission are hardly implemented. Rabies is known to be present in all continents except Antarctica. It infects domestic and wild animals. Under-reporting of rabies cases also militates against mobilization of resources. Intervention programmes from international community for the elimination of human dog-mediated rabies are not top priority. We must interrupt rabies disease progression by partnering in its control and management. This is why this public document is supporting the rabies awareness campaign.
STAGES OF RABIES ATTACK
Rabies is infectious to mammals and essentially manifests in three stages. The first is a 1-3 days period which is characterized by behavioural changes. This is known as the prodromal stage. The second is the excitative stage which lasts for 3-4 days. This is often known as “furious rabies” stage. Here, the affected animal is hyper-reactive to external stimuli and can bite anything in close contact. The third is the paralytic stage which lasts beyond 4 days. This is associated with damage to motor neurons in the brain and other organs.
DIAGNOSIS OF RABIES
It is crucial to emphasize that the early stages of rabies before death can be difficult to diagnose. Epidemiological factors such as season, geographic location, patient’s age and travel history are important. Also possible exposure to bites, rodents and ticks, may help direct the diagnosis. However, it should be noted that no tests are currently available for rabies in humans before the onset of the clinical stage of the infection. And unless the rabies-specific signs of hydrophobia or aerophobia are present, the clinical diagnosis may be difficult.
SIGNS AND SYMPTOMS OF RABIES
Rabies signs and symptoms are progressive and vary with the stage of the infection. The signs and symptoms may include convulsions, unusual or unexplained tingling, pricking, burning or itching sensation at the bite site. There may be low-grade fever (102o F or lower) and muscle spasms. Observed are acute pain at the site of the bite, restlessness or abnormal behavior and swallowing difficulty (drinking causes spasms of the voice box). This is due to paralysis of throat muscles. Lack of coordination owing to rear limb paralysis is commonly observed. Other signs and symptoms are headache and drooling or hyper salivation caused by paralysis of facial muscles. Noticed are general weakness or discomfort, insomnia, anxiety and confusion. There are presentations of slight or partial paralysis in areas of the body and agitation. Hydrophobia (fear of water), delirium and aerophobia (abnormal and persistent fear of flying following severe anxiety) are reported.
COMPLICATIONS OF RABIES
Rabies presents some vital complications that bring it to the fore as a critical disease affecting humanity and other mammals. The complications include depression or periods of mania, lethargy and fatal inflammation of the brain and spinal cord. Coma and death (caused by cardio-respiratory arrest) within days of the onset of severe symptoms are notable complications.
MODE OF TRANSMISSION OF RABIES
Transmission of rabies virus begins when infected saliva of a host is passed to an uninfected mammal. The most common mode of transmission is through the bite and exchange of virus-containing saliva of an infected host. Transmission can also occur when infected material, usually saliva, have direct contact with human mucous or fresh skin wounds. Human-to-human transmission by bite can be possible. Other rarely documented routes are contaminated mucous membranes (eyes, nose, mouth), aerosol and organ transplantation.
ANIMALS THAT CAN TRANSMIT RABIES
Rabies virus infects most animals and transmits the disease to humans and other animals. The vectors which most likely transmit the rabies virus include:
- Pets and farm animals which are cats, cows, dogs, ferrets, goats, horses, cattle and rabbits.
- Wild animals which are insectivorous bats, beavers, coyotes, weasels, bears and foxes. Others are monkeys, wolves, raccoons, skunks, yellow mongoose and woodchucks.
- Principal rabies hosts: Generally, the principal rabies hosts and transmitters today are dogs, wild carnivores and bats. In Asia and parts of the Americas and Africa, dogs remain the principal host. The rabies virus survives in widespread rural fauna reservoirs. It is present in the animal populations of almost every country in the world.
VACCINATION AGAINST RABIES
Vaccines to prevent human rabies have been available for over one hundred years. Most deaths from rabies occur in countries with inadequate public health resources and limited access to preventive treatment. These countries also have few diagnostic facilities and almost no rabies surveillance. There is no specific treatment for rabies infection. Though a small number of people have survived rabies, the disease is usually fatal. For that reason, anyone thought to have been exposed to rabies receives series of shots of rabies vaccines. This helps to prevent the infection from taking hold and spreading to vital organs of the body.
Safe and effective vaccines can be used for pre-exposure vaccination. This is recommended for travelers who spend a lot of time outdoors, especially in rural areas. Vaccines are available for cyclists, campers or hikers as well as expatriates living in areas with significant risk of exposure to rabies. Pre-exposure vaccination is also recommended for people in certain high-risk occupations. The laboratory workers dealing with live rabies virus and other rabies-related viruses are among. People involved in professional or otherwise activities that might expose them to rabid animals in rabies-infested areas need vaccines. Children under 15 years of age, living in or visiting high risk areas are at higher risk and need to be vaccinated. They innocently play with animals and may receive more severe bites without reporting.
Vaccination is the most cost-effective strategy for preventing and eliminating rabies in dogs and other rabies prone animals. Vaccination of animals, mostly dogs has decimated the number of human and animal rabies cases in several countries. Recent increases in rabies deaths in Africa, Asia and Latin America suggest that rabies is re-emerging as a serious public health concern.
HOW TO STAY AWAY FROM RABIES INFECTION
It is important to avoid contact with biting mammals known to be rabies reservoir or vectors. Animals that look sick or has an abnormal behavior should be avoided. Stay away from wounds or mucous membranes contaminated with rabid animal’s saliva. Do not allow unprovoked bite by an unvaccinated animal. Do not have unnecessary close contact with animals you are not familiar with. Traveling or living in developing countries like Africa and Southeast Asia without adequate medical protection should be avoided.
Other things that need to be avoided are activities that are likely to put you in contact with wild animals that may harbour rabies virus. Such activities are exploring caves where bats live or camping without taking precautions to keep wild animals away. Avoid working in a laboratory with the rabies virus without sufficient protection. Avoid wounds on the head or neck to prevent rabies virus from migrating speedily to the brain. Handling wild animals or strays without adequate protection should be avoided. The practice of allowing dogs to lick feces from the anus of children should be disallowed.
QUICK SAFETY PRECAUTIONS AGAINST RABIES VECTORS
Quickly go to the medical emergency room or any health care provider if any animal bites you. Get vaccinated if you work in a high-risk occupation or travel to countries with high rate of rabies. Ensure your pets receive the proper vaccinations from qualified veterinarian. Follow quarantine regulations on importing dogs and other mammals into disease-free countries. Treat local wound or bite or scratch as soon as possible to prevent rabies and death. Wash the wound from an animal bite immediately with soap and water for 10 to 15 minutes. And apply antiseptic such as povidone-iodine, iodine tincture, aqueous iodine solution or alcohol (ethanol) before contacting healthcare providers for necessary interventions. If any animal bites you, try to gather as much information about the animal as possible. Call local animal control authorities to capture the animal and observe it for signs that will guide appropriate medical action against rabies. If mucous membranes such as eyes, nose or mouth are exposed to rabies they should be flushed well with water immediately. Within 10 days of infection, get a course of potent and effective rabies vaccine or immunoglobulin that meets WHO recommendations.
Contact an animal control officer upon observing a wild or stray animal, especially if the animal is acting strangely. If you awake to find a bat in your room, assume that it has bitten you. A bat that fly into your room while you are sleeping may bite you without waking you. Keep bats out of your home by sealing any cracks and gaps or seek help from local experts to keep them out. Also, a bat near a small child or disabled should be assumed to have bitten the victim. Such should be reported for immediate medical attention.
Keep your pets confined, and supervise them when outside. This will keep them from contacts with wild animals especially rabid animals. Keep small pets like rabbits and guinea pigs protected from predators. They should always be inside or in protected cages away from wild or rabid animals.