The hierarchy of controls concept, often used to address measures taken to reduce workplace hazards, is useful when considering infection control strategies in veterinary settings.^7,13–17 Below is a “Hierarchy of Controls” pyramid that can be used to determine effective ICPB procedures such as changes in facility design, policies or procedures, and wearing protective clothing. The top tiers are generally considered more effective at minimizing hazards (e.g., pathogen exposure) than the lower tiers.^15,16 Often, a combination of control measures are needed to effectively reduce exposures.¹⁶

Elimination of sources of pathogen exposure involves physically removing (or preventing) the hazard (i.e., pathogen) from entering the facility.^15,16 Although completely eliminating infected animals from a facility is unlikely to occur, measures can be taken to prevent patients from infecting the general population. While elimination controls are the most effective at reducing hazards, they are often the most difficult to implement.¹⁵

Engineering controls include measures designed into the facility to remove a hazard at its source or to improve compliance with infection control procedures.^4,7,15,16 These measures can be highly effective but generally have higher initial costs.^4,13–17

Administrative controls include protocols or changes to work practices, policies, or procedures to keep patients or staff separated from a known hazard as well as providing staff with information, training, and supervision for these measures. Administrative controls address the way people work and how animals move through the hospital (traffic flow) when an onsite infectious disease is known or suspected.^4,13–17

Personal protective equipment (PPE) includes the use of special clothing and equipment to protect staff and patients who may be exposed to known or suspected pathogens.^13,15,16 PPE places a barrier between staff and an exposure risk (e.g., infected animal, diagnostic specimens) and with appropriate use, helps prevent the spread of pathogens between animals and within the practice. The use of PPE is considered a relatively less effective means of controlling exposures because it relies on human factors such as staff compliance and appropriate education and training.^4,15 Although less effective, lower tiers (e.g., PPE) remain critical for effective infection control and should be used when indicated.

Click here for examples of hierarchy of control measures that can be applied in a veterinary hospital.