[en] The results of a serological survey carried out in northeastern Spain to estimate the seroprevalence to Salmonella spp. and to determine potential risk factors are presented. Sera were obtained from farms submitting serum samples to the Regional Diagnostic Laboratory (RDL) for the diagnosis of other infectious diseases included within official eradication/surveillance programs, and farm data collected through a questionnaire. Out of 6,182 pig sera (217 farms) analyzed 1,219 (19.7%) were positive (optical density, OD ≥ 40%). More than 70% of the herds presented ≥ 1 seropositive animal indicating that salmonellosis was widespread. In a multivariable logistic mixed regression model seroprevalence was associated with farms where birds were visible inside the fattening units (OR = 2.1; 95% CI: 1.3-3.2) or that shared workers with other pig farms (OR = 2.5; 95% CI: 1.4-4.7). Seropositivity also increased when farmers used footwear exclusive for the farm (OR = 3.1; 95% CI: 1.3-7.3) or pigs were fed mostly with pellets (OR = 1.7; 95% CI: 1.1-2.6). It was also higher during the fall and winter months. The presence of a changing room and shower in the farm was negatively associated with it (OR = 0.5; 95% CI: 0.3-0.8). Most risk factors could be mitigated through strict hygiene and biosecurity measures, but the high (&gt; 40%) within-herd seroprevalence observed in many herds may challenge the capacity of intervention of animal health authorities.

[es] Se presentan los resultados de un estudio serol&oacute;gico realizado en explotaciones porcinas del Noreste de Espa&ntilde;a para estimar la seroprevalencia frente a Salmonella spp. y determinar posibles factores de riesgo asociados. Los sueros se obtuvieron a partir de aquellos enviados por las explotaciones al Laboratorio Regional de Diagn&oacute;stico para el diagn&oacute;stico de otras enfermedades infecciosas sometidas a erradicaci&oacute;n/vigilancia oficial, y los datos sobre las explotaciones se recogieron mediante un cuestionario. De un total de 6.182 sueros de cerdo (217 granjas) analizados 1.219 (19,7%) resultaron positivos (densidad &oacute;ptica, DO &ge; 40%). M&aacute;s del 70% de los reba&ntilde;os presentaron al menos un animal positivo, indicando que la salmonelosis est&aacute; ampliamente distribuida en la regi&oacute;n. Seg&uacute;n un modelo multivariable mixto de regresi&oacute;n log&iacute;stica, la seroprevalencia se asoci&oacute; con granjas en las cuales se ve&iacute;an aves en el interior de las naves (OR = 2,1; IC 95%: 1,3-3,2) y tambi&eacute;n con granjas que compart&iacute;an trabajadores (OR = 2,5; IC 95%: 1,4-4,7). Se observ&oacute; que la seropositividad se incrementaba cuando los trabajadores usaban botas exclusivas en la explotaci&oacute;n (OR = 3,1; IC 95%: 1,3-7,3) o al alimentar a los cerdos principalmente con alimento granulado (OR = 1,7; IC 95%: 1,1-2,6). La seroprevalencia tambi&eacute;n fue superior durante los meses de oto&ntilde;o e invierno. La existencia en las granjas de vestuarios y duchas para el personal se asoci&oacute; negativamente con la seroprevalencia (OR = 0,5; IC 95%: 0,3-0,8). La mayor&iacute;a de los factores de riesgo podr&iacute;an controlarse a trav&eacute;s de estrictas medidas de higiene y bioseguridad, pero el gran n&uacute;mero de reba&ntilde;os que presentaron alta seroprevalencia (&gt; 40%) puede poner a prueba la capacidad de intervenci&oacute;n de las autoridades sanitarias oficiales.