Infection control, biosecurity, biocontainment, and biosafety are essential functions at all health care operations, including veterinary practices.
All veterinarians at some level recognize and act to prevent adverse outcomes in patients. However, as major outbreaks of health care-associated infections (HAIs) at veterinary hospitals have become increasingly publicized,1-15 it has become obvious that coordinated infection control practices are a critical component of delivering high-quality care at veterinary facilities, especially those with large caseloads and those that specialize in intensive care of patients.
This threat is relevant to all veterinarians and all hospitals. Two surveys of veterinary referral hospitals at American Veterinary Medical Association (AVMA)-accredited institutions reported that a majority had experienced outbreaks of HAIs in the preceding 5 years (81% and 65%, respectively, for the two surveys),16,17 and at least 45% recognized more than one outbreak.16 The two agents most commonly associated with outbreaks reported in both surveys were Salmonella enterica and methicillin-resistant Staphylococcus aureus (MRSA), but 12 other agents were also implicated. More than half of the participating hospitals had to restrict admissions to protect patients and allow mitigation, and a large number of the equine hospitals were temporarily closed. Even with very limited surveillance, more than half of these same hospitals recognized significant illness in veterinary personnel during the study periods. The agent most commonly implicated in human illnesses was Cryptosporidium parvum.16,1The standard of veterinary care is changing such that sporadic occurrence and outbreaks of HAIs may no longer be interpreted as unavoidable accidents when coordinated measures are not routinely used to minimize their likelihood. Our understanding of infection control issues in veterinary medicine has also advanced significantly during the previous two decades.
As such, what may have passed as sufficient for infection control in veterinary practices 10 or 20 years ago may often not be sufficient today. It is also important to realize the important part that infection control and biosecurity must play in ambulatory practices and on our clients' premises. Inherently, healthy animals with lower contagious disease risks represent a smaller proportion of hospital populations than they do among populations in their home environments. However, veterinarians are obviously called on to contact those animals most likely to be shedding contagious pathogens regardless of whether this is in hospitals or in the field. In addition, there are several examples in which patients discharged from hospitals were the likely source of viral and bacterial infections for animals in their home environments.6,9 The magnitude of this potential hazard is perhaps best illustrated by the equine herpesvirus 1 (EHV-1) outbreak, which occurred in association with the National Cutting Horse Association Western National Championship in Ogden, Utah, in May 2011.18,19 It is likely that exposure to a single horse that was shedding EHV-1 at this event resulted in more than 165 horses developing clinical disease that was known or suspected to be caused by EHV-1; at least 13 of these horses were euthanized. The outbreak spanned at least 10 western U.S. states and 2 Canadian provinces. Clearly the need to apply sound biosecurity and infection control practices extends well beyond the walls of veterinary hospitals.It is also clear that dramatic outbreaks are not the only circumstances in which HAIs affect patients. Lessons learned in human health care settings show that endemic HAIs typically create a much greater overall burden in exacerbated morbidity and mortality than do epidemics. Unfortunately, information from veterinary care settings regarding rates of endemic HAIs is limited, but there is no reason to believe that the situation would be different.
Based on limited numbers of systematic studies conducted in veterinary hospitals, the burden of disease associated with sporadic or endemic HAIs is substantial in veterinary patients. A recent multicenter study performed in five academic referral hospitals reported that nosocomial events monitored as seven different clinical syndromes were recognized during hospitalization in 19.7% (95% confidence interval [CI] = 14.5% to 26.7%) of equine patients admitted for gastrointestinal (GI) disease at a rate of 3.9 events per 100 days of hospitalization (95% CI = 2.9 to 4.3 events per 100 hospitalization days).20 Other studies reported in equine patients have principally focused on HAIs related to surgical site infections.21,22 These rates are not dissimilar from rates reported for HAIs among humans in critical care settings. Thus these notable outbreaks of HAIs and the emerging awareness of the importance of endemic occurrences should create an acute awareness that dramatically sharpens our focus on preventing all types of HAIs, including those that seem sporadic. Although the discussions in this chapter are mostly framed in the context of hospital settings, the concepts and issues apply much more broadly to ambulatory practices and animals' home premises.