Canine rabies in the United States, 1971-1973: study of reported cases with reference to vaccination history.

From 1971 through 1973 629 reported cases of rabies in dogs, concentrated in the Appalachian area, upper Mississippi drainage, Texas, and Louisiana, were reported in the US. States bordering the Atlantic and Pacific oceans had fewer cases. There was a recurring seasonal pattern of cases with a peak in March and April and a low point in August and September. Most of the cases involved transmission from wildlife vectors rather than dog-to-dog transmission. Most of the dogs were owned (87%), unvaccinated (87-90%), and adult (72%); most demonstrated unaggressive behavior (74%) and had exposed humans (75%). A history of vaccination was reported for 60 of the dogs. There were 21 cases of apparent vaccine failure involving all the types of vaccines in use during the study period. The attack rate for unvaccinated dogs was estimated to be 14 to 19 times higher than for vaccinated dogs. Since canine rabies in the United States is predominantly a problem in owned, invaccinated pets, vaccination and licensing of dogs should be mandatory. Surveillance should be continued to ensure that any resumption of dog-to-dog transmission will be rapidly detected and to monitor efficacy of vaccines in current use.