Saturday, December 12, 2015

Rabies in Haiti

Haiti has the highest incidence of rabies in the Western Hemisphere

Rabies is a viral (Lyssavirus) infection transmitted in saliva or other secretions from infected animals, typically via a bite. Unvaccinated dogs are the most common animal. Other potential reservoirs include cat, coyote, wolf, fox, skunk, raccoon, and bat species.  

The virus is highly neurotropic (likes nerve cells). After the bite, the virus infects the local peripheral nerves and then slowly travels along these nerves towards the brain. There is a long incubation period (20 to 90 days) before the cells reach a spinal ganglion. Once the virus reaches this level the first symptoms develop with pain or paresthesia at the site of the bite. Thereafter the virus travels rapidly into the brain. Once the virus reaches the central nervous system the infection is 100% fatal! 

Once the brain is infected, the individual develops muscle fasciculation (twitching), focal or generalized convulsions, and this is followed by paralysis, coma, and death. Autonomic instability might develop with rapid heart and respiratory rate, high blood pressure, tearing, sweating, and salivation.

The best treatment is prevention with rabies vaccination of domesticated animals. Domesticated dogs are not routinely vaccinated in Haiti, and this provides the opportunity for human infection. Individuals who work with animals should be routinely vaccinated. 

If an individual is bitten by a potentially rabid animal, treatment should include human rabies immune globulin (HRIG) or one of two inactivated rabies vaccines and this must be accomplished as soon as possible during the incubation period and before the virus reaches the central nervous system. If the vaccination status of the animal is not known, the animal should be observed for ten days for signs of canine rabies. 

The Center for Disease Control recommends post exposure prophylaxis with intramuscular administration of either of two different inactivated rabies vaccines. The dose for prevention is 1 ml of the vaccine administered in the deltoid or in the upper outer thigh in infants. 

HRIG should be administered to any person not previously vaccinated against rabies, at a dose of 20 IU/kg (for adults and children). As much of the HRIG dose as possible should be administered at the injury site and the remainder as a deep intramuscular injection in the gluteal area. HRIG may be administered as long as 7 days after the first dose of vaccine if it is not immediately available.




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