Survival analysis of factors affecting incidence risk of Salmonella Dublin in Danish dairy herds during a 7-year surveillance period.

摘要: A national surveillance programme for Salmonella Dublin, based on regular bulk-tank milk antibody screening and movements of cattle, was initiated in Denmark 2002. From 2002 to end 2009 the prevalence test-positive dairy herds reduced from 26% 10%. However, new infections spread S. Dublin between continued occur. The objective this study investigate factors affecting incidence risk infection Danish 2003 2009. Herds were considered at when they had been test-negative least four consecutive year-quarters (YQs), either start period or after recovery infection. Survival analysis performed a dataset including 6931 with 118,969 YQs risk, which 1523 failures (new events) occurred. Predictors obtained register data tested multivariable, proportional hazard model allowing recurrence within herds. During October December higher (hazard ratio HR = 3.4, P = 0.0005) than rest year. Accounting delay responses infection, indicates that introduction bacteria most frequent July October. Purchase cattle previous 6 months associated (HR = 2.5, P < 0.0001) compared no purchase herds. Increasing local prevalence, herd size somatic cell counts also increasing failures. The effect prior time-dependent; following logarithmic decline time risk. markedly first year becoming again, then approached without known 2–3 years test-negative. This showed need maintain high level biosecurity 3 years prevent recurrence. Furthermore, general recommendations wishing protect their against include avoidance contact Large herds, neighbours obtain biosecurity.