Animal bite and rabies prophylaxis

What rabies is

Rabies is caused by a lyssavirus. There are two settings for the vaccine: preexposure vaccination, and post-exposure prophylaxis after a bite or scratch from an animal infected with the rabies virus.

The incubation is long, and that is why the patient is not admitted to be watched: rabies virus incubation ranges from 30 to 90 days, with some reporting up to 7 years. The patient should receive immunoprophylaxis and be sent home.

The picture once it begins is psychosis, seizures, aphasia, muscular twitching, delirium and death, and hydrophobia with neurologic symptoms is what to consider in individuals who are cave spelunkers.

Which animal matters. In the United States the predominant threat to humans is bats, which most commonly carry the virus. Small rodents, squirrels, rats and chipmunks, and lagomorphs are herbivores and do not carry the virus.

Causes and risk

A bite is grouped with the other exposures when the likely pathogen is being chosen. A dog or cat bite points to Pasteurella multocida and Capnocytophaga canimorsus. A human bite points to Eikenella corrodens, anaerobes and S. aureus.

The other exposures on the same list are:

• Salt water: Vibrio vulnificus, and other Vibrio species.
• Fresh or brackish water: Aeromonas species and Plesiomonas shigelloides.
• Neutropenia: P. aeruginosa and other Gram negatives.
• Meat or fish: Erysipelothrix rhusiopathiae, one of the occasional causes that also include S. pneumoniae, H. influenzae, Legionella spp. and fungal causes.
• Immunosuppressed patients, mostly: Helicobacter cinaedi or other related species, coagulase-negative Staphylococci, Cryptococcus spp., Candida spp, Nocardia and nontubercular mycobacteria.

Without such an exposure the pathogens are Streptococcus species, usually group A, that is S. pyogenes, for most cases, with the other Streptococcus groups B, C and G, especially group G; and Staphylococcus aureus, of which MRSA now dominates both in and out of the hospital.