Prevalence and risk factors for Lawsonia intracellularis, Brachyspira hyodysenteriae and Salmonella spp. in finishing pigs in Polish farrow-to-finish swine herds

Abstract

AbstractThe aim of the study was to estimate the herd-level, within-herd prevalence, the frequency of mixed infections and risk factors forL. intracellularis,B. hyodysenteriaeandSalmonellaspp. in selected farrow-to-finish Polish pig herds. A total of 254 pooled fecal samples were collected from 9 to 24 week-old pigs in 70 herds. Real time PCR for detection ofL. intracellularisandB. hyodysenteriaewas performed. ForSalmonellaspp. bacteriological examination was performed. The herd-level prevalences ofL. intracellularis, B. hyodysenteriaeandSalmonellaspp. among examined herds were 65.7%, 1.4% and 8.6%, respectively. The within-herd prevalences (in positive herds) forL. intracellularis,B. hyodysenteriaeandSalmonellaspp. were 51.5%, 75.0% and 30.4%, respectively. All herds with diarrhea observed during sampling were infected withL. intracellularisand 60% of herds with no diarrhea at the moment of sampling were infected withL. intracellularis(p=0.035). In herds with more than 200 sows the prevalence ofSalmonellaspp. was significantly higher compared to herds with less than 200 sows (p=0.027). In herds where all-in/all-out (AIAO) was respected, prevalence ofL. intracellulariswas significantly lower than in herds where this rule was not kept (p=0.024). Obtained results confirm thatL. intracellularisis the major cause of bacterial diarrhea in finishing pigs. The present study identified AIAO and herd size as a risk factor, at the herd level, forL. intracellularisandSalmonellaspp., respectively.