Oral communication in Brucellosis 2011-International Research Conference

September 22^nd, 2011

Saez-LLorente JL., Sanz C., Minguez O., Fernandez F., Garcia P., Duran M., Perez AM., Mardones F., Alvarez J. and Dominguez L.

The national eradication program implemented by Spain in the mid 1990s was successful in reducing bovine brucellosis (BB) prevalence to < 0.2% in 2010. However, this decreasing trend has not been homogeneous throughout the country due, at least in part, to epidemiological conditions in certain areas referred to as “Special Incidence Areas” (SIA), in which BB infection prevails. With the objective of reducing BB prevalence, additional measures, such as vaccination and/or stamping out, may be implemented in SIAs. Here, the results of eradication programs implemented from 2002 through 2010 in four SIAs were assessed. The four SIAs were located in different Autonomous Regions with different epidemiological conditions in which different control strategies were applied. In Cantabria (SIA 1, n≈4700 herds, mostly extensively managed beef herds) and in Castilla la Mancha (SIA 2, n≈1100 herds, mostly intensively managed dairy herds) confirmed positive herds were subjected to stamping out. In the SIAs located in Castilla and León (SIA 3, n≈5200 herds) and Extremadura (SIA 4, n≈2800 herds), in which most of the herds were extensively managed cattle herds, cows and replacement heifers were vaccinated with RB51 and S19, respectively. The annual prevalence trend and time to achieve a “controlled status” (sustained reduction of initial prevalence) in each SIA-Local Veterinary Unit (LVU) was assessed using regression and survival
analyses, respectively. The adjusted annual rate mean of decrease varied among SIAs (SIA 1=-20.4%, 95% CI: 3.6-34.3; SIA 2=-35.2%, 95%
CI: 32.5-37.9; SIA 3=-44.3, 95% CI: 36-51.5; SIA 4=-47.5%; 95% CI: 38-55.5). Exploration of cumulative hazard curves suggested that reduction of initial prevalence was more rapidly achieved, and less consistent, using stamping out and that decreasing trend was largest for SIAs in which vaccination was implemented. Most important, re-emergence of disease after achieving the controlled status was only observed in 1/26 LVU and a similar prevalence level was observed after 4-5 years of implementation of the control program for both vaccination and stamping out-based control strategies. These results suggest that both vaccination and stamping out may be effective strategies to control BB infection in endemically infected settings

	Servicio de Zoonosis Emergentes, de Baja Prevalencia y Agresivos Biológicos (NED). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).
	Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).