Bluetongue

diagnosis and significance in the bovine animal

Abstract

Bluetongue (BT) is an important virus infection of cattle even though it is clinically expressed in only 5 to 10% of the infected cattle. There are a few bovine practitioners in areas of low BT prevalence who believe this disease is essentially exotic in the United States (US). Other practitioners have had personal experience with the disease and believe it is a “sleeping giant” that causes severe reproductive problems in their clients’ herds. Thus, discussion of the disease evokes a wide spectrum of views and attitudes, possibly more than any other infectious disease of cattle. The infection has been referred to as “a political disease,” “a pain in the neck,” “a mystery,” “a riddle” and recently, “a bigger threat than you think.” In the World Animal Review article a preceeding editorial comment stated that “bluetongue is one of the diseases that, for many countries, ranks high in the list of exotic diseases that need to be controlled, and that prompted the convening of the FAO Expert Consultation on Emergency Disease Control.” Most bovine practitioners’ experience with BT is related to serology and the certification of cattle free of the infection. Some practitioners have had direct experience with the devastating consequences of infection that include “abortion storms,” infertility stillborns, and various fetal anomalies and dysfunctions. In this report, the authors will attempt to dispel some of the confusion about BT by discussing diagnostics, the perpetuation of BT virus (BTV) and the health problems that infection produces in cattle.