A case study investigating the effects of emergency vaccination with Brucella abortus A19 vaccine on a dairy farm undergoing an abortion outbreak in China

Abstract Brucellosis is an important zoonosis that results in substantial economic losses to the livestock industry through abortions and reduced milk yield. This study investigated abortion outbreak a dairy herd then explored effects of emergency vaccination with Brucella abortus A19 vaccine on incidence A full dose (6 × 10 —12 colony forming units, CFU) was administered subcutaneously calves non-pregnant heifers, 8 adult cows pregnant replacement heifers. Rose Bengal Test used screen infection status positive samples were tested C-ELISA. Animals for both tests considered spp . The animal-level seroprevalence brucellosis 23.1% (95% CI: 17.0, 30.2), attributable fraction seropositive animals 89.1% 64.3, 96.7). odds seropositivity significantly higher aborted compared calved normally (OR = 21.4, 95% 4.4, 168.4). Cows sheds A2 C1 10.2 1.4, 128.0) 17.0 2.8, 190.3) times more likely be than shed B1. Antibodies not detectable most heifers 12 months post-vaccination. effectiveness preventing estimated 56.8% 15.8, 77.8) entire herd, but increased 86.7% 98.1) when only primiparous considered. Furthermore, significant increase average 305-day yield one-year after also observed relative previous three years. It concluded undergoing effectively indirectly vaccination.