Emergence of raccoon rabies in Connecticut, 1991-1994: Spatial and temporal characteristics of animal, infection and human contact

The North American raccoon rabies epizootic continues to expand, now affecting most of New England. In 1990, raccoons became the vertebrate most often reported rabid in the United States. Emergence of this zoonosis poses increasing, but poorly defined risks to humans. This study analyzed various demographic, environmental, and behavioral factors associated with animal infection and human exposure before and during the epizootic in Connecticut. Rabies virus infections among terrestrial vertebrates were analyzed from 1985 through 1994. From March 1991, when the first case was diagnosed, through December 1994, 2,522 of 13,147 animals tested were found positive for rabies viral antigen. Forty-seven percent of the raccoons tested were infected, representing 88.0% of all animals found positive. Domestic animals constituted only 1.7% of positive test results, but 40.6% of the tests performed. The epizootic wave of transmission advanced approximately 30 km/year. Most rabies-positive wild animals were taken from private properties, usually near houses. Possible human exposures involved 939 people on 556 occasions through direct contact (20.7%) or indirectly through another animal (79.3%). Of 3,239 domestic animals exposed to rabies-positive wild animals, 18.4% lacked vaccination. Rabies has become enzootic in Connecticut and risk to humans and animals persists. The public health burden is considerable, yet knowledge is lacking to develop sustainable prevention strategies.