Abstract
According to the CDC, rabies is a zoonotic viral disease (meaning it is spread from animal to human based on contact) that is transmitted from animal to human in the event of being bitten or scratched. About 120,000 animals are tested for rabies every year and about 6% are found to be rabid. Approximately 55,000 people die from rabies each year, and more than 9/10 of the deaths occur in Asia and Africa. Rabies is a disease that endangers the health and lives of animals and humans (World Health Organization).
History
Scientists believe that the disease rabies was first formed in either Africa or Asia, but the disease was not actually recognized in The New World until 1753 when dogs were thought to be infected inside of a Virginia colony. Before rabies was officially recognized as a disease, people had strange ways of “curing” the symptoms. In the 1600’s, since rabies is said to cause a fear of water, victims of the disease were nearly drowned in nearby lakes in hopes of “expelling the disease” (Alvin & Silverstein 14-15). An equally dramatic treatment was amputation, which was thought up by Greek physician Claudius Galen. In some lucky incidences, if the infected limb was amputated early enough, it usually prevented the disease from developing and spreading throughout the victim’s body (Alvin & Silverstein 14-15).
Description of Rabies
Rabies is a zoonotic disease that is caused by a bullet shaped virus called a lyssavirus. Rabies attacks the central nervous system and is most likely fatal if not caught early. Coincidentally, the disease was named after one of its most common symptoms. The word rabies is a Latin word that means “rage or fury” (Alvin & Silverstein 23). Carriers (animals) of rabies include raccoons, skunks, bats, foxes, wild dogs, farm animals, and occasionally domestic dogs and cats. The disease is contracted through any form of contact with the saliva of an infected animal (bites, scratches, saliva going into an open wound) (Alvin & Silverstein 32). As for common locations in which rabies occur (in the United States), each individual state gathers its own information every year to see where rabies is most commonly spread/contracted. In addition to that, the CDC publishes a report called “Rabies Surveillance In the United States” (CDC, 2016). Nationally, it is very common for specific towns to sponsor rabies clinics in order to prevent the spread of the virus and keep it under control.
Prevention
How can rabies be prevented? Rabies can be prevented very easily. First, enjoy wildlife, but only from a distance; as to not risk coming in contact with a potentially dangerous or infected animal. According to the CDC, more ninety percent of rabies cases were in wild animals such as raccoons, skunks, foxes, and bats. Second, do not approach stray animals and immediately report them to animal control. Keep children under close supervision when around domestic animals or wildlife. A child is much more likely than an adult to approach an animal, regardless of its behavior or symptoms. Third, keep pets updated with rabies vaccinations. Vaccinating animals against rabies prevent pets from becoming infected from wild animals, and thus transmitting the disease to people. Indoor pets should receive up to date rabies shots as well. Fourth, supervise pets outside so that they do not come in contact with wild and potentially rabid animals. Fifth, keep lids on garbage cans and do not leave pet food outside. Food left outside can attract stray or wild animals, thus increasing your chances of coming in contact with a potentially infected animal. Sixth, if an individual is at risk of contracting rabies due to their job or travels, said individual should receive a pre-exposure vaccine. Examples of people that should receive the pre-exposure vaccine include those who work with rabies in a laboratory setting, wildlife control officers, domestic animal control officers, and those who are traveling to a country where rabies is widespread (CDC, 2016). The pre-exposure vaccine is also important for those who are traveling to a country where rabies is widespread in which medical care may be delayed or difficult to receive all together.
There are preventative measures that can be taken. Simple ways to prevent animals/pets from contracting rabies are to vaccinate them; do not allow them to wander; and to keep them out of contact with unknown, stray animals. Ways to prevent rabies among humans are to avoid contact with unknown stray animals and to not approach any animal showing the symptoms of rabies. Also, report animals showing the symptoms of rabies to local health officials in order to prevent the disease from spreading to other animals (Alvin & Silverstein 65).
If an individual does get bitten by a wild animal that is not available for testing, wash the wound thoroughly with soap and water immediately. Additionally, report to a physician immediately after being bitten or coming in contact with a wild animal. Due to the fact that sometimes the wild or domestic animal that caused the bite is not available for testing, it is best to receive the post-exposure rabies vaccine in order to prevent the disease from possibly developing or spreading. Commonly, people get post-exposure rabies vaccines because the domestic or wild animal that bit them is not available for testing. One of the most important steps in preventing rabies is educating those at risk about responsible pet ownership and how to avoid exposure to rabies. Animal vaccination clinics and community awareness are critical to tackle this disease and improve human and animal health around the world. Well implemented prevention programs have been the only successful efforts to reduce and eliminate rabies from domestic dog populations, which subsequently has been shown to nearly eliminate human cases of rabies (CDC Foundation, 2016).
Transmission
The rabies virus is transmitted through saliva or brain/nervous system tissue. Rabies can on be transmitted by coming in contact with these specific bodily excretions and tissues.
It is important to remember that rabies is a medical urgency, but not an emergency. Decisions on whether or not to visit a doctor should not be delayed. Wash any wounds immediately. One of the most effective ways to decrease the chance for infection is to wash the wound thoroughly with soap and water (CDC, 2016).
Signs/Symptoms
What are the symptoms of rabies and how are they diagnosed? Unfortunately, once the symptoms of rabies begin to occur, it is already too late and nothing currently available in medicine can cure the disease. Death usually occurs two to ten days after the symptoms start (Medline, 2016). Symptoms of rabies in animals include either becoming unnaturally friendly or hostile towards humans and foaming at the mouth. Early symptoms of rabies in humans include itching, tingling, or general discomfort at the site of the bite, fever, headache, fatigue, and confusion. As the disease progresses, symptoms such as delirium, insomnia, anxiety, agitation, hallucinations, and paralysis may begin to occur as well (Medline, 2016).
Diagnosis
As for diagnosis, there is no way currently to diagnose a living animal with rabies. The animal must be euthanized before running a series of tests called dFA (direct fluorescent antibody), which searches for rabies in brain tissue (CDC, 2016). The dFA test is based on the observation that animals infected by rabies virus have rabies virus proteins (antigen) present in their tissues. Because rabies is present in nervous tissue (and not blood like many other viruses), the ideal tissue to test for rabies antigen is brain. The most important part of a dFA test is fluorescently-labeled anti-rabies antibody. When labeled antibody is incubated with rabies-suspect brain tissue, it will bind to rabies antigen. Unbound antibody can be washed away and areas where antigen is present can be visualized as fluorescent-apple-green areas using a fluorescence microscope. If rabies virus is absent, there will be no staining (CDC, 2016). Although there are other methods in diagnosing rabies, such as histologic examination, immunohistochemistry, electron microscopy, and amplification methods, the Direct Fluorescent Antibody Test has proven to be the most accurate of all the diagnostic tools.
Because of its high sensitivity and specificity, in comparison to virus isolation methods, the DFA test is the “gold standard” diagnostic method for rabies and has been rigorously evaluated by international, national, and state health laboratories. The DFA test is currently the only recommended diagnostic method for routine rabies determination in animals in the United States (CDC, 2016). As for diagnosis of rabies in humans, the individual should go directly to his/her physician upon being bitten by a thought-to-be rabid animal.
Treatment
In order to prevent the spread of disease, a series of vaccines must be issued. The only way for the vaccines to be effective is if they are received immediately or shortly after contact with the infected animal (Aisworth, 2009). Due to the availability of vaccines, the death rate of rabies in the United States is only one or two people each year. Such deaths can be contributed to those who were not aware of the serious risks of domestic or wild animal contact/bites. Over the last 100 years, rabies in the United States has changed dramatically. More than 90% of all animal cases reported annually to CDC now occur in wildlife; before 1960 the majority was in domestic animals. The principal rabies hosts today are wild carnivores and bats. The number of rabies-related human deaths in the United States has declined from more than 100 annually at the turn of the century to one or two per year in the 1990’s. Modern day prophylaxis has proven nearly 100% successful (World Health Organization 2016).
In the United States, human fatalities associated with rabies occur in people who fail to seek medical assistance, usually because they were unaware of their exposure (CDC, 2016).
However, rabies is still a huge problem in developing countries. Nearly all of the 55,000 rabies deaths globally are caused by the bites of rabid dogs. Rabid dogs are a growing problem in Africa, Asia, and the Middle East. Unfortunately, most people that receive bites from rabid dogs in developing countries die from the disease. This can be attributed to a lack of public awareness, lack of responsible pet ownership, the high expense of rabies vaccines, and a lack of medical care. In the future, scientists hope to create more low-cost vaccines to be given to places like Africa, Asia, and the Middle East in order to drop the overall death rate (World Health Organization, 2016). In addition to trying to create more low-cost vaccines, scientists are also trying to create longer-lasting vaccines. Pharmaceutical companies are trying to make a vaccine that lasts for the entire life of an individual (Alvin & Silverstein 96-99). Scientist and doctors are also working on ways to keep citizens of developing countries educated about the risks of rabies.
Post Mortem Considerations & Conclusion & References
TBA