Rabies is an acute, progressive infection of the central nervous system (CNS) caused by neurotropic viruses which are transmitted in the saliva through the penetrating bite of rabid animals. Tens of millions of human exposures and tens of thousands of deaths due to rabies may occur globally each year. Rabies is mainly transmitted via saliva through the penetrating bite of infected animals, which may not exhibit features of disease (especially carnivores and bats). Rabies virus, which is neurotropic, must be inoculated through intact skin (e.g., by a bite or scratch) or licked onto preexisting nonintact skin (e.g., open wounds or abrasions) or onto mucosal surfaces via saliva or contact with infected neural tissue, where it enters the peripheral nervous system at the site of the inoculation. The virus then travels through peripheral nerves to the CNS.
All mammals are susceptible, but dogs and other wildlife (bats, coyotes, foxes, jackals, mongooses, raccoons, skunks, and wolves) are the most important vectors because they bite readily, eat small mammals that may be naturally infected, infect other canines by fighting, and may have daily contact with humans. Monkeys are a potential but uncertain source; nevertheless, monkey bites must be treated as a potential rabies risk.
Bat rabies is transmitted by bat bites or scratches (which may not be noticed) or, more rarely, by inhalation of aerosolized virus (e.g., by laboratory workers) or bat saliva in caves where numerous bats congregate. Bat bites are a cause of concern and an indication to consider pre-exposure prophylaxis (PrEP).
The rate of exposure to rabies in travelers is roughly estimated to be in the range of 16 to 200 per 100,000 travelers and for half of travelers, the bite occurs in early parts of travel, often within the first 10 days. Children are at higher risk because of their inquisitive nature, attraction to and inability to recognize behavioral signals from animals (especially dogs), small stature, and the possibility that they may not report an exposure.
Rabies vaccine may be indicated for travelers going to any country with rabies (especially canine rabies); the decision to vaccinate may also be based on the likelihood of repeat travel to risk areas or long-term travel to high-risk areas.
