Seroprevalence of Anaplasma marginale in Texas cattle.

To our knowledge the seroprevalence of Anaplasma marginale in Texas has not been reported. The objective of this study was to estimate the point seroprevalence and spatial distribution of Texas cattle persistently infected with A. marginale. This was a cross-sectional observational study examining serum collected from 12,000 adult cattle marketed in 23 selected Texas auction markets during the second week of July 2011. A random subset of those cattle comprising 1835 individuals was evaluated for persistent infection with A. marginale using a commercial cELISA for antibody detection. The pooled apparent seroprevalence for cattle tested at auction markets across the state was 15.02% (95% CI: 11.02-19.53%), with markets in the western portion of the state demonstrating prevalence ⇒ 30%. The winter tick, Dermacentor albipictus is involved in the biological transfer of A. marginale and is prevalent in west Texas. Producers in endemic and non-endemic areas should be encouraged to determine the infection status of replacement cattle in order to implement effective management strategies for the control bovine anaplasmosis.