Rabies, a form of viral encephalitis, was discovered by an Italian physician, Girolamo Fracastoro in the early 16th century. Rabies is a viral infection that affects the brain and spinal cord and is transmitted through the saliva of an infected animal. "Rabies infection frequently causes cytoplasmic eosinophilic inclusion bodies (Negri bodies) in neuronal cells" (2). Rabies often causes terrible suffering and is almost always fatal. Rabies is named after its transmission by the bite of a 'mad dog'. The name is Latin and means "to rage". (6). Signs of rabies in animals include: change in behavior, problems swallowing, increased drool and saliva, paralysis, and death. In humans, signs usually occur 30-90 days after a bite (2).
Rabies may cause frightening symptoms such as: crawling sensation in the skin, wild excitement, sore throat, hallucinations, tingling at the site of the bite, and paralysis (1). Education is important for the prevention of rabies. "People should vaccinate their pets and have a healthy attitude toward wildlife" (5). Steps that can be used to prevent exposure to rabies include: keeping pet shots up to date, following leash laws, feeding pets indoors, sealing basements and porches, and reporting stray animals to authorities. Although there is no cure for rabies, vaccinations and immune globulin are used as first line of defense for humans exposed to the disease (5). Passive immunization provides immediate, but temporary, protection by injecting antibodies into the individual. It is recommended by CDC that patients should be given a rabies shot following the first treatment. Although it takes time for the body to make antibodies, the antibodies offer longer-lasting protection (7). Pasteur originally developed the rabies vaccination in 1885. Rabies vaccine is given to individuals upon exposure of the virus. Individuals with high exposure to rabies-- such as rangers, veterinarians, and animal handlers, should get a preexposure vaccine series (5). Domestic animals such as cats, dogs, horses, and cattle should be vaccinated to control the spread of the disease. This is the most effective control measure of preventing rabies in animals and subsequent human exposure (7).
Vaccines today are highly effective. They help the body's immune system destroy the disease in its early stages (4). Today, there are three human rabies vaccines made from killed rabies virus; Human diploid cell vaccine (HDCV), Rabies adsorbed (RVA), and Purified chick embryo cell culture (PCEC) (7).
Virulence mechanisms that contribute to the disease process include G protein, glycoprotein, and cytopathic effects (6). Key tests for identification include Flourecent Antibody test. This is the method of choice used by public health laboratories (3). When labeled antibody is incubated with rabies-suspect brain tissue, it will bind to rabies antigen. Other tests for diagnosis include: Electron microscopy, histologic examination, IHC, and isolation in cell culture (2). Polymerase chain reaction-based typing methods as well as monoclonal antibody analysis, are used beyond the standard fluorescent test. These methods are used when transferring reagents to the laboratories (3). Although rabies in humans is uncommon, individuals should be aware of its effects and how to prevent exposure to the disease.
References
(1) Centers for Disease Control and Prevention. (2002). Rabies Warning Signs. Retrieved from http://www.cdc.gov/ncidod/dvrd/kidsrabies/Warning/warning.htm
(2) Centers for Disease Control and Prevention. (2001). Rabies The Virus. Retrieved from http://www.cdc.gov/ncidod/dvrd/rabies/the_virus/virus.htm
(3) Hanlon, A.C., Smith, J.S., Anderson, G.R. (1999) Recommendations of a national working group on prevention and control of rabies in the United States. Retrieved from http://www.cdc.gov/ncidod/dvrd/rabies/ Professional/publications/ working_group/hanlon2.pdf
(4)Healthwise. (2001). Rabies Treatment Overview. Retireved from http://my.webmd.com/encyclopedia/article/4115.19959
(5) Hingley, A. (1996). Rabies On the Rise. Retrieved from http://www.fda.gov/fdac/features/996_rab.html
(6) MMID. (1999). Rabies Virus. Retrieved from http://www.medinfo.ufl.edu/year2/mmid/bms5300/bugs/rabies.html
(7) National Institute of Allergy and Infectious Diseases. (2002). Fact Sheet Rabies. Retrieved from http://www.niaid.nih.gov/factsheets/rabies.htm