The great majority of reported incidents of rabies each year occur in wild animals such as bats, skunks, foxes, and raccoons.
Dogs are the most important uncontrolled global source of rabies in humans. Children are among those at greatest risk of rabies infection. Children are more likely to be bitten by a dog and are also more likely to be severely exposed due to multiple bites in high-risk sites on their bodies. Severe exposure to rabies makes prevention of it in the future more difficult, unless access to appropriate medical care is available immediately.
Domestic pets such as dogs and cats cause most animal bites, although dogs cause more than cats. Cat bites are more likely than dog bites to cause an infection. Bites from domestic animals that have not been immunized and wild animals have the potential to spread rabies infections. Rabies remains more common in bats, foxes, skunks, and raccoons than domesticated pets. Animals such as squirrels, rabbits, or other rodents rarely carry rabies.
Transmission of Rabies
Every species of mammal is susceptible to rabies viral infection, yet only a few species are important as carriers for the disease. In America there are some distinct strains of the rabies virus that have been identified in skunks, foxes, raccoons, and coyotes. There are a number of species of bats who are carriers for strains of the rabies virus as well.
Transmission of the rabies virus commonly starts when saliva from an infected host is passed to a host that is not infected. While rabies transmission has rarely been documented through other means, such as contamination of the nose, eyes, or mouth, it has occurred. Rabies transmission may also occur through aerosol transmission or through organ or corneal transplantations, although it is extremely rare.
Signs and Symptoms of Rabies
The rabies virus infects the central nervous system of the creature involved; human or not, ultimately causing disease in the brain and ultimately death. The early symptoms of rabies in people are similar to those of a number of illnesses and include headache, fever, and generalized weakness and discomfort. The person may experience a prickling or itching sensation at the site where they have been bitten.
Progression of the disease brings symptoms that are more specific, such as:
The symptoms above can last for between two and ten days and are considered to be a part of the acute phase of a rabies infection. Once the clinical signs of the infection appear the disease is almost always fatal. Treatment of the person with the infection is usually supportive. There are fewer than ten documented cases of people who have survived clinical rabies; only two have not had a history of either pre or post-exposure treatment measures.
Rabies is diagnosed in animals through the direct fluorescent antibody (DFA) test. The DFA test looks for the presence of rabies virus antigens in brain tissue. Where human beings are concerned; however, a variety of tests are required in order to achieve a diagnosis of rabies infection.
A rabies infection in a human being demands a rapid and accurate laboratory diagnosis to ensure the person receives treatment in time. Within a period of a few hours, a diagnostic laboratory has the ability to determine whether or not an animal that has bitten a person is rabid and inform health care workers treating the infected person. The lab results might save the person from unnecessary psychological and physical trauma, as well as financial burden, if the animal is not infected with rabies.
Treatment of Rabies
Rabies is one-hundred percent preventable through the administration of human immune globulin and a round of injections with rabies vaccine. Despite this fact, greater than fifty-five thousand people, mostly in Asia and Africa, die from rabies each year. Approximately one person in these nations dies from rabies every ten minutes.
Treatment of rabies after a person has been exposed consists of administering a dose of human rabies immune globulin plus four doses of rabies vaccine on the same day the person was exposed. The person receives the same administration of immune globulin and rabies vaccine three, seven, and fourteen days after exposure to rabies. The vaccine is administered through an injection in a muscle, commonly in the person's upper arm. The vaccinations are extremely effective at preventing rabies if it is administered at soon as possible after a person is exposed.
If someone has already received the vaccinations before they were exposed to rabies, or received them after being exposed at another time, they will only require two doses of the vaccine after being exposed to rabies again. In either of these cases, the person will receive the vaccine on the day they were re-exposed to rabies, and then again three days later. The person will not need human rabies immune globulin again.
It is uncommon for people to have any adverse reactions to the rabies vaccine or the immune globulin shots. Medical science today uses newer vaccines that cause fewer adverse reactions than the ones previously available. The person may experience some mild and local reactions to the vaccine such as redness, pain, swelling, or itching around the site of injection. On rare occasion, the person may experience symptoms that include nausea, headache, muscle aches, abdominal pain, or dizziness. The immune globulin shot may have side-effects such as localized pain, or a low-grade fever.
When a person has been exposed to rabies and begins the vaccination process, it is important for them to continue the process of vaccination. Rabies prevention is a serious issue and changes should not be made to the scheduled doses of vaccine. Doctors also recommend that people who have been exposed to rabies receive a tetanus shot, something that needs to be updated every ten years.