Rabies is a serious illness caused by a virus that infects the nervous system.
Rabies produces a characteristic rapidly progressive disease of the central
nervous system (brain and spinal cord nerves). Rabies is generally fatal if
untreated.
Early warning signs of rabies include anxiety,
difficulty swallowing, convulsions, and, in some patients, paralysis.
In the United States, domesticated dogs and cats
are not primary carriers of the rabies virus. Rather, raccoons, skunks,
foxes, bats, and ferrets are more likely to harbor the disease and directly
infect humans. When domesticated pets are infected, there may be a history of
previous interaction with these wild animals.
The rabies virus is present in the saliva of
infected animals and is introduced to humans by bites, scratches, or licking of
open wounds.
In studies of rabies acquired from bats, direct
contact may not be necessary since documented cases of human rabies has been
established after exposure to bat-infested caves. An airborne mechanism of
transfer of the rabies virus has been hypothesized in such cases.
In humans, the incubation period between exposure
to the virus and development of clinical symptoms averages 4-6 weeks.
The "gold standard" test for the
diagnosis of rabies involves demonstration of the rabies virus in the brain of
the affected animal.
Only seven patients are known to have survived once
the symptoms of rabies developed, immediate treatment of all individuals
suspected of having been exposed to rabies is mandatory.
Initial care for a rabies-exposed person includes
vigorous washing of wounds with soap and water. Consideration of the patient's
tetnus status should be also done at this time.
After local care is completed, both passive
immunization (with rabies immune globulin-RIG) and active immunization (with
human diploid cell vaccine-HDCV) must be considered. Specialized treatment
protocols published by the Centers for Disease Control and Prevention (CDC)
exist to help management decision making in such cases. Side effects of HDCV
occur in approximately 25% of recipients and include pain, local swelling,
headache, nausea, muscle aches, and dizziness. Selected groups of
individuals whose occupation (e.g., veterinarian, animal handlers, etc.) or
avocation (e.g. cave explorers) are candidates for consideration of pre-exposure
vaccination against rabies.
Immunization of domesticated dogs, cats and ferrets
is mandatory and has been paramount in the control of rabies in the United
States.
Useful links:
CDC - Rabies
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