| prevalence of bluetongue virus serotype 4 in cattle in the state of sao paulo, brazil. | bluetongue (bt) is considered endemic in several regions of brazil. the state of sao paulo was divided into 7 cattle production regions (circuits) according the different systems of breeding, operational and logistical capacity of the state veterinary service. at least 1 animal from each property (a total of 1,716 farms) was tested by competitive elisa for the presence of antibodies against btv. sero‑positive sera were subsequently also tested by virus neutralization tests (vnt) using serial dil ... | 2016 | 27723043 |