Environmental recommendations

Heating, ventilation, and air conditioning

Consideration of proper heating, ventilation, and air conditioning is critical for practice infection control. Appropriate ventilation is particularly important for reducing airborne diseases, excessive moisture and dust, and chemical fumes from disinfection products that make patients and staff susceptible to infection as a result of damaging their airways. Ventilation should not cause movement of air from areas with known infected patients to other areas of the practice. Spaces where infected patients are held should be vented to the outside. The number of air exchanges per hour (the rate at which the complete volume of air inside a building or room is replaced with fresh outside air) is critical for good ventilation. Recommendations vary between 5 and 8 air exchanges per hour. Whenever possible, three levels of air filtration are recommended in a practice: (1) a wire mesh to remove hair and large matter from the air; (2) a finer (less porous) filter placed within the air ducts to remove dust and other particulate matter; and (3) a high-efficiency particulate air filter to remove viral particles and very fine particulate matter. Highefficiency particulate air filters are expensive, and appropriate replacement of these filters may not be affordable for all practices. Regardless of type, filters must be cleaned or changed frequently to prevent infectious buildup and hair-clogged vents. Ventilation systems need to be inspected regularly and updated as needed.

Rodent and insect vectors

Some important veterinary pathogens can be transmitted by wild rodents or insect vectors (e.g., fleas, ticks, mosquitoes, flies). Pest management practices include examination of patients upon arrival for ectoparasites; immediate treatment of patients with fleas, ticks, or mites; and appropriate housing (e.g., isolation) until resolution. Dry pet food and garbage should be stored in metal or thick plastic containers with pest-proof lids. Prompt disposal of food waste and other materials (e.g., feces) that may attract rodents or insects is critical. Sealing potential pest points-of-entry, including maintenance of intact window screens, is important. Elimination of potential rodent nesting and mosquito breeding sites around the practice (e.g., brush, debris, empty food bowls, clogged gutters) prevents onsite pest reproduction. Consultation with a pest control expert is recommended if a particular infestation is present, or for additional guidance and information.

Spills and waste

Veterinary biomedical waste is a potential source of zoonotic and nonzoonotic pathogens. In the United States, biomedical waste is defined and regulated at both state and municipal levels.51 Veterinary medical waste includes sharps, tissues (anatomic waste), highly contaminated materials, and deceased animals.

It is beyond the scope of these guidelines to describe spill cleanup and veterinary biomedical waste management in detail. However, basic guidelines are summarized here. Used sharps are considered biomedical waste and should be disposed of in accordance with regulations from municipal and state authorities. Use approved, puncture-resistant sharps disposal containers to remove, store, and dispose of needles and other items capable of causing punctures. Ensure such containers are readily available and used everywhere sharps are handled to prevent sharps injuries to staff and clients. Nonanatomical waste saturated with blood, such as blood-soaked lap sponges and gauze, or materials used to clean up a spill of blood or infectious secretions, are also disposed of as biomedical waste. Liquid waste such as drained thoracic fluid, abdominal fluid, irrigated solutions, excretions, and secretions may usually be poured carefully down a toilet or drain connected to a sanitary sewer or septic tank. Local, state, and federal regulations may dictate maximum volume of blood or body fluids permitted to be poured into the sanitary sewer. If the fluid is likely to splash or spray during disposal, appropriate PPE should be worn. Waste should be contained in a leak-proof container or bag discarded with the waste (plastic garbage bag). Urine and feces are not biomedical waste, nor is disposable equipment that has come in contact with an infectious animal (e.g., examination gloves, gowns, bandage materials not saturated with blood).

Potentially infectious, contaminated materials may pose a risk to practice personnel, patients, and waste disposal personnel. Precautions should be taken to minimize contamination of the practice environment and the risk to people and animals from potentially infectious waste. These include double-bagging of materials from isolation areas. If the inside of a waste container becomes contaminated, the container should be thoroughly cleaned and disinfected after emptying. All waste from an isolation room should be treated as potentially infectious; trash from these areas should be removed by appropriately gloved and gowned personnel. Contaminated articles should be either discarded or taken for additional cleaning and disinfection. Rural practices, where biomedical waste disposal services may not be available, may be able to make arrangements with a local human hospital or other medical facility to have waste disposed of with human hospital waste.


Single-use, disposable items are ideal for infection control, but their disposal produces tremendous waste and an environmental burden. Laundering reusable bedding, gowns, scrubs, towels, and other items is therefore an important component of infectious disease control. Linens and professional garb can serve as fomites, transporting pathogens within the practice and outside the practice into the community. Microbe populations on soiled laundry are significantly reduced by dilution and further by the mechanical action of washing. Hot air drying further eliminates microorganisms. As transport to individuals’ homes or other facilities increases ICPB risks, professional garb (e.g., scrubs, lab coats) should be washed onsite or by a specialized commercial laundry facility equipped to clean medical laundry. Practices should have appropriate laundry facilities or laundry services to accommodate cleaning of these items daily or more frequently if necessary. To reduce contamination with infectious organisms and health risks to staff, appropriate PPE (i.e., gloves and dedicated laboratory coat) should be worn by those performing laundry duties. Linens with gross contamination should be assessed to determine if they can be effectively cleaned. If not, they should be properly discarded. Otherwise, gross organic material should be removed prior to washing.

Additional precautions should be taken for laundry from isolation rooms and infected animals. These items should be washed and processed separately from other practice laundry while wearing appropriate PPE to prevent spread of microbes. Items from infected animals should be presoaked in diluted bleach (9 parts water:1 part household bleach) for 10 min to disinfect prior to machine washing. Isolation-room laundry should be washed in hot water with bleach, per manufacturer’s instructions. After bleaching and washing, laundry should be completely dried in a separate load from any other laundry and returned to isolation.

Appropriate antimicrobial stewardship

The concept of antimicrobial stewardship, or the judicious use of antimicrobials, including when not to use these agents, has emerged in the last decade as a necessary approach across health professions to prevent adverse events and selection for drug-resistant infectious pathogens. The misuse of antimicrobials in human and veterinary healthcare is one of the key factors leading to the current epidemic of antimicrobial resistance. More information on the overall concept of antimicrobial stewardship and how it is applied in veterinary practice as advised by the American Veterinary Medical Association can be found at here. Previously created American Association of Feline Practitioners-AAHA guidelines discuss the judicial therapeutic use of antimicrobials. Information on more longstanding antimicrobial stewardship practices in human hospitals and long-term care facilities in the United States, referenced in the American Veterinary Medical Association document, can be found here.

Personnel vaccination

Although not always financially viable for all hospitals or staff within a hospital, personnel vaccination is an important component of occupational health and safety. Decisions regarding vaccination of staff should consider the risk of exposure, the severity of disease, whether the disease is treatable, the transmissibility of disease, and the quality and safety of the vaccine. It is recommended that all veterinary personnel who might have contact with animals should be vaccinated against rabies, except in areas that have been formally declared rabies-free (e.g., Hawaii).7 This includes lay staff that might have periodic animal contact, such as receptionists. Rabies vaccines for humans are generally considered safe and highly effective. Learn more about preexposure vaccinations here.

Other vaccinations including tetanus and annual influenza may be appropriate depending on the practice setting and other exposure risks. Additional information is available.7

These guidelines are supported by a generous educational grant from Virox Animal Health™.