Mammalian reservoirs and the changing epidemiology of rabies in the United States

The epidemiology of rabies in the United States has changed dramatically over the past few decades. Greater than 90% of all animal rabies cases reported annually to the Centers for Disease Control and Prevention now occur in wildlife, whereas before 1960 the majority were domestic animals. The principal rabies reservoirs today are wild carnivores and bats, infected with many different types of rabies virus variants. Annual reporting of human deaths have fallen from more than 100 at the turn of the century to one to six per year, despite major outbreaks of animal rabies in several distinct geographic areas. Most recent human rabies cases acquired in the United States are the result of infection with rabies virus variants associated with bats, although the exact incident leading to exposure has been difficult to define. Many recent deaths have occurred in persons who failed to seek post-exposure treatment, presumably because they did not recognize a risk in the animal contact leading to the infection or failed to recognize that contact had occurred. Although these human rabies deaths are rare, estimated public health costs associated with disease detection, prevention, and control have risen, exceeding millions of dollars each year.