Raccoon rabies in space and time

Rabies is the only pathogen to play a role in a Disney movie. While defending the children who costar in the 1957 film against a rabid coyote, the canine hero of “Old Yeller” is bitten and acquires the infection. Eventually, Old Yeller becomes rabid and moves on to the great casting kennel in the sky, and a younger understudy then helps to placate the mortified children. If Disney were to remake the film, they might have to replace canine rabies with raccoon rabies, which is now the major strain of rabies in the United States; more than 85% of the rabies cases currently recorded in the United States are reported from raccoons. Most of these are from a strain of rabies that continues to expand its geographical distribution. This rabies strain was given a new lease on life in 1976, when Jimmy Carter was elected to the United States presidency. As several members of Carter's cabinet and personal staff missed going “‘coon hunting” over the weekend, they had some raccoons imported into Virginia from Georgia (1). The strain of rabies that came with these raccoons initiated an outbreak of rabies in the local raccoon population that has been steadily expanding ever since, predominantly in a northeasterly direction (2). The annual United States budget to control rabies is $300 million; a further $15 million is spent annually on postexposure prophylactic treatment of the 18,000 to 20,000 people who are exposed each year (3, 4). Understanding the spatial spread and local dynamics of an infectious disease such as rabies is central to the design of control strategies for introduced infectious diseases. The paper by Childs (5) provides important new insights into the mechanisms that determine the rate of spread of raccoon rabies. As recently as 1997, Mark Wilson pointed out …