Evolution of a Salmonella Biosecurity Program Over a 10-Year Period

1. Introduction
There have been numerous reports detailing outbreaks of nosocomial salmonellosis in large animal hospitals.^1–3  Morbidity and mortality rates in these outbreaks have varied with the offending Salmonella serovar, species of patients affected, and facility size and design. Prevalence of and risk factors for fecal shedding of Salmonella spp. by hospitalized horses as well as hospital practices that may contribute to spread of disease (e.g., lack of proper isolation facilities, common use of stomach tubes, inadequate disinfection protocols) have also been documented.^3–5  In the face of an outbreak, containment efforts have included depopulation with or without closure coupled with a thorough hospital cleaning and disinfection.^1–3,6

In response to each outbreak, biosecurity protocols are reviewed, and often more detailed and costly infection control practices are implemented. These typically include establishing traffic flow patterns, detailing specific indications for isolation of patients, cohort housing of patients at various risk levels, using barrier precautions, screening patients for fecal shedding of Salmonella spp., monitoring efficacy of disinfection practices with environmental cultures, and encouraging staff to practice good hygiene.⁶  Although these general practices can be established in all large animal hospitals, specific details of each hospital’s biosecurity program necessarily vary with facility design (and limitations) and resources dedicated to the effort. Thus, specific protocols differ among institutions and, as a result, comparison of the efficacy of biosecurity programs between different hospitals is challenging. [...]