Association between non-typhoidal Salmonella isolated from commercial poultry sheds and associated factors in Paraná, Brazil: Cross-sectional retrospective study

The epidemiology of salmonellosis in poultry is complex, which makes it difficult to identify the origin and spread of this disease in poultry farms. The aims of this study were to characterize the spatial distribution of Salmonella enterica in epidemiological units in Paraná, Brazil; and to investigate correlations between this microorganism and associated factors. Among the epidemiological units, 78 of 243 (32.10%) were positive. Spatially, the northwestern and western regions had higher concentrations of positive cases than the other regions. In bivariate analyses, the presence of other animal species in the epidemiological unit (prevalence ratio, PR = 0.64; 95% confidence interval, CI = 0.43­0.95; p = 0.022) and proximity to establishments at risk (PR = 0.51; 95% CI = 0.32­0.81; p = 0.001) did not influence positivity, but the average population per poultry shed (between 30,501 and 32,500; PR = 2.57; 95% CI = 1.72­3.83; p = 0.001) was associated with Salmonella positivity. Multiple logistic regression demonstrated that the average population per poultry shed, presence of surrounding risk-posing establishments and presence of surrounding poultry sheds produced a significant multiple model for S. enterica. The results indicated that the presence of S. enterica may be related to higher density broiler in poultry sheds, presence of surrounding poultry sheds, proximity between positive and negative epidemiological units and altitude of the municipality. The information obtained showed that some factors were related to positivity for this microorganism and emphasizes the importance of serotyping to obtain other epidemiological data.