An acute encephalitis caused by a virus of the Rhabdoviridae family of Lyssavirus and in nearly uniformly fatal in unvaccinated individuals.
Transmitted when broken skin or a mucous membrane is contaminated with saliva from an infectious mammal.
Unique rabies virus variants exist and are associated with specific animal reservoirs.
Two varieties of rabies exist: encephalitic, occurring in 80% of cases and paralytic, accounting for 20% of cases.
After a 1-3 month incubation the development of an acute, rapidly progressive encephalomyelitis develops and death of the patient occurs within 20 days.
Usually the virus will replicate briefly within the first site of infection, within the muscle tissues.
Viral replication then leads to viremia and the virus spreads to its secondary site of infection, the central nervous system (CNS).
Upon infection of the CNS, secondary viremia results and symptoms usually begin.
Vaccination at this point is useless, as the spread to the brain is unstoppable.
Vaccination must be done before secondary viremia takes place for the individual to avoid brain damage or death.
Only two cases reported in the U.S. in 2003 and no more than 6 cases reported in any year in the last decade.
Rare in the U.S with 27 cases reported from 2000-2008.
In United States all but two cases of rabies reported in the years 2000-2010 were associated with bats.
Transmission is usually through a bite, which may be unrecognized.
Can be transmitted by aerosolized exposure such as may occur in the cave with a large population of bats.
Transmission has occurred with organ or tissue transplantation.
During 1980-2009 39 of 43 reported cases of acquired in the United States were associated with a bat exposures.
Most cases in the U.S. associated with bats, whereas in most developing countries dogs are the most common reservoir and vector species.
Virus is present in animal reservoirs with transmission through the bite of an infected animal.
Domesticated animals made up 7.9% of all rabid animals in 2006.
In 2006 total of 6,940 cases reported to the CDC of cases in wild or domesticated animals and three cases in humans.
Globally an estimated 55,000 people die of rabies annually, most casess attributable to dog bites.
Following animal bites or scratches the areas should be washed thoroughly with soap and water to reduce the risk of infection.
The following exposure the administration of rabies immunoglobulin and rabies vaccination can prevent the disease process.
Healthy animals that bite a person should be confined and observed for 10 days-if these animals become ill or die in this period of time they should have their brains examined by a state lab for evidence of rabies.
Patients exposed to rabies should receive post exposure prophylaxis.
Clinical signs of disease are most often evident with encephalitic form of the disease and includes hydrophobia, muscle spasms, and altered mental status.
Raccoons are the most frequently reported rabid animals in United States, however only one case of a raccoon rabies virus variant has been reported in humans.
Progession occurs in five stages: incubation, prodrome, acute neurologic phase, coma, and death.
Patients rarely survive the coma stage.
A pre-exposure rabies vaccine series is indicated for individuals with long stays in endemic areas of Latin America, Asia, Africa, where the rabies threat is constant and access to adequate post exposure rabies immunoglobulin vaccine is limited.
The highest risk countries include the Indian sub continent, Thailand, Vietnam, and most sub-Saharan African countries.
Postexposure prophylaxis rabies vaccine regimens can be intradermal rabies vaccine at two separate sites and two visits.