Seroprevalence of bovine anaplasmosis in the southern US

Abstract

Bovine anaplasmosis, caused by Anaplasma marginal, is the most prevalent tick-transmitted disease of cattle worldwide and a major obstacle to profitable production in the U.S. The introduction of anaplasmosis into a naive herd can result in a reduced calf crop and increased cull and mortality rates in infected adult cattle. The cost of anaplasmosis to the US beef industry is estimated to be over $300 million annually. Control of anaplasmosis in the U.S. is predicated on biosecurity and administration of antimicrobials both of which require knowledge of regional prevalence for implementation to be successful. The last reported prevalence of anaplasmosis in cattle in the southern U.S. ranged from 2% to 24%. However, the test used to determine the prevalence, complement fixation, is no longer considered reliable. Therefore, true prevalence of anaplasmosis in this region is likely much higher than previously reported.