U.S. Concerns over Bluetongue

摘要

M. Enserink's news of the week story "exotic disease of farm animals tests Europe's responses" (8 February, p. 710) describes how bluetongue, a disease caused by a vector-borne orbivirus, has spread widely in ruminant livestock in Europe since 1999. Unlike Europe, which has only experienced bluetongue disease in the past few years, the United States and the Americas in general have been endemic for several bluetongue virus (BTV) serotypes since first reported in the 1950s. The historically prevalent U.S. BTV serotypes, though pathogenic in sheep, have caused little to no disease in U.S. cattle. The vectors of these serotypes have been identified, and their distribution has in the past explained the epidemiology of BTV in the United States (1).