Infection Control Programs for Dogs and Cats

Chapter 11

Infection Control Programs for Dogs and Cats


The primary role of an infection control program is to reduce the incidence of hospital-acquired infections (HAIs) by patients, staff, and visitors to a small animal hospital. Infection control programs in veterinary hospitals have largely evolved from evidence and protocols from the human health care setting, together with our understanding of transmission pathways for veterinary pathogens. In recent years, several factors have led to an increased rate of adoption of infection control programs by veterinary hospitals, such as an increased prevalence of multidrug-resistant bacterial infections among small animal patients, the appearance of more studies that support the common occurrence of transmission of hospital-associated and zoonotic pathogens in the veterinary setting, the requirement for an infection control program in veterinary teaching hospitals for accreditation purposes, and increased scrutiny of hospital-associated and zoonotic infections to protect hospitals against litigation.

Infection Control Programs

Every small animal hospital should have an infection control program. At a minimum, this should consist of an infectious disease control officer, a written infection control protocol, regular training of staff, and documents that record all training and surveillance efforts. In large hospitals, formation of an infectious disease control committee may be required. In this situation, the infectious disease control committee could consist of an internist or criticalist with an interest or training in infectious diseases, a veterinary clinical microbiologist, a nursing supervisor, a safety officer, the hospital administrator, and the hospital director. There should be adequate personnel and communication so that proper coverage is maintained when one individual is absent or unavailable. All personnel who work in a veterinary hospital, as well as visitors, should be familiar with the infectious disease control personnel as well as procedures and policies listed in the infection control protocol. Documentation of training should be maintained for all hospital personnel.

The Hospital Infection Control Protocol

The objective of a hospital infection control protocol is to provide a standard procedure for the control of infectious diseases in the hospital, in order to minimize animal-to-animal, animal-to-human, and human-to-animal transmission of pathogens. Adherence to the infection control protocol can also reduce transmission of infectious agents between personnel through increased hand washing and reduction of fomite contamination. The infection control protocol is a legal document and should be regularly updated by a designated hospital infection control officer or committee. Each hospital should develop a protocol that is tailored to address specific practice requirements and the hospital design, purpose, and equipment used. Additional special precautions may need to be described for hospitals that see avian and exotic pet animal species, and in geographic locations where serious zoonotic diseases such as rabies and plague are endemic (see Chapters 13 and 55).

The infection control protocol details practices that optimize hygiene such as hand washing, the use of protective clothing, cleaning and disinfection, and appropriate disposal of infectious agents. Specific infectious disease control procedures to be followed in different areas of the hospital (radiology, surgery, the intensive care unit, isolation, wards) can be included, as well as policies on antimicrobial use. The protocol can also be used to educate staff about routes of transmission, the potential for zoonotic transmission, specific transmission precautions for infectious diseases that are seen within the practice, and immunization requirements, such as those for rabies (see Chapter 13).

Standard Precautions

All animals that enter a veterinary hospital are potential carriers of pathogens that may be spread to other animals or people. Animals may be colonized with multidrug-resistant bacteria, often without showing evidence of disease due to these organisms. Pet owners may carry these organisms on their hands and clothing. Standard precautions such as hand hygiene and the wearing of routine protective clothing can minimize the spread of these bacteria around the hospital and to immunocompromised animals.

Hand Hygiene

Frequent and proper hand and wrist washing to remove transient flora on the hands has been proven as the most important component for prevention of the spread of infectious diseases in human hospitals.1 Signs that outline proper hand-washing technique, including the use of paper towels to turn off the faucet, posted adjacent to basins around the hospital can improve compliance among staff. Online videos that demonstrate proper hand-washing technique are available for educational purposes.2 Guidelines for hand washing are shown in Box 11-1. Antibacterial soap should be used, and all surfaces of the hands should be rubbed together, which should include the backs of the hands, between the fingers, and under the fingernails, for a total hand-washing time of at least 20 seconds. In order to prevent chapped skin, which can harbor bacteria, water used for hand washing should not be too hot, and hand lotion should be applied regularly. Behaviors such as keeping fingernails short, avoidance of artificial and/or polished fingernails or hand jewelry, or wearing jewelry on a chain around the neck instead of on the hand can be encouraged. Meticulous hand hygiene is particularly important for personnel who work frequently with immunocompromised animals, such as emergency and critical care personnel. The use of touch-free taps and paper towel dispensers can also reduce transmission of bacteria during hand washing.

Alcohol-based hand sanitizers are a more convenient form of sanitization. These can be provided in multiple locations around a hospital, or travel-sized bottles can be carried in a coat pocket. At least one to two full pumps or a 3-cm diameter pool of the product should be dispensed onto one palm. All surfaces of the hands and wrists should be rubbed with the product until it has dried. Use of soap and water, rather than hand sanitizer, is recommended when there is gross contamination with organic matter, or when exposure to alcohol-resistant pathogens such as Clostridium spp. spores or parvovirus might have occurred. However, the availability of hand sanitizers improves compliance in busy hospital situations, is associated with lower rates of dermatitis than medicated soaps, and is recommended for routine hand sanitation in human health care settings by the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO).3,4

The use of gloves prevents contamination of the hands with microorganisms, prevents exposure to bloodborne pathogens, and reduces the risk of transmission of microorganisms from personnel to animals. However, gloves are not a substitute for proper hand hygiene. Guidelines for wearing disposable gloves are shown in Box 11-1. Gloves should be promptly removed after use, before other surfaces are touched, and hands should then be washed. If a glove is torn or punctured, it should be removed and replaced as soon as possible.

Hospital Attire

Nonsurgical Areas

Staff should be encouraged to wear dedicated hospital attire that is not worn elsewhere, so that hospital pathogens are not transported to and from locations outside the hospital. At the minimum, protective clothing such as clean laboratory coats or hospital scrubs and closed-toe shoes must be worn in nonsurgical areas. Sleeves must be short enough or rolled up to expose the wrists, and laboratory coats changed whenever gross soiling occurs. In the absence of gross soiling, coats should be changed daily. If neckties are worn, they must be secured in place by an outer layer of clothing or a tie pin so that they cannot be contaminated as a result of contact with patients or environmental surfaces and act as fomites, as has been shown to occur in human hospital environments.5 Long hair must be tied back so that it does not drape on animals and hospital surfaces. Face shields and a clean gown should be worn during procedures that are likely to generate splashes or sprays of blood and body fluids. Gowns must be made of impervious material and tied on securely and correctly. Soiled gowns must be removed as soon as they are no longer required and face shields cleaned.

General Animal Handling Precautions

All animals seen at a veterinary hospital should undergo a history and physical examination by a veterinarian to determine the likelihood and nature of any transmissible infections that might be present. Ideally, client beds, blankets, collars, and leashes should not be brought into the hospital, where they could become contaminated. Animals should always be placed in cages that have been cleaned and disinfected appropriately. Disposable thermometer sleeves should always be used on thermometers. Equipment should not be shared between animals unless it has been cleaned and disinfected. Diets that contain raw meat and bones should not be fed or stored in the hospital, because they commonly contain and can potentially transmit foodborne gastrointestinal pathogens.7 The handling of sick animals should be minimized, unless required for patient care.

Because some infections can be transmitted through bites and scratches, staff should be educated on bite and scratch avoidance, such as the use of restraint devices, protective gloves, and warning signage on cages and medical records. Should bites or scratches occur, they should be vigorously flushed and immediately washed with water and chlorhexidine or a dilute iodophor solution, and the bite reported to appropriate officials as necessary. Deep wounds could be irrigated with pressure using a syringe without an attached needle. If a bite occurs, medical attention should be sought as soon as possible. All bites or scratches must be documented and consideration be given as to why the injury occurred, so that procedures or training to prevent future injuries can be implemented if necessary.

Consumption of food and drink should be limited to parts of a hospital where patient care and the handling of biologic specimens and medications do not occur. Food and beverages should not be left out open on benches for long periods. Microwaves used for animal care purposes should not be used to heat food intended for people.

Transmission-Based Precautions

Transmission-based precautions are instituted for selected patients that are confirmed to be or suspected to be infected or colonized with important transmissible pathogens. Transmission-based precautions are used in combination with standard precautions. In the human hospital setting, three types of transmission-based precautions have been developed—airborne, droplet, and contact precautions (Table 11-1).8 Airborne precautions are used to prevent the transmission of diseases by droplet nuclei (particles <5 µm). Transmission by droplet nuclei occurs with diseases such as measles, varicella, and pulmonary tuberculosis. The precautions for human patients involve isolation in a single-bed, negative-pressure room and the wearing of high-density respirator (N95) masks. These resemble surgical masks but filter 1-µm particles with an efficiency of at least 95% and must be properly fitted. Airborne contact precautions are rarely necessary in hospitals that treat only dogs and cats, but could be considered when animals suspected to have pneumonic plague, tularemia, or Mycobacterium tuberculosis infection. Droplet precautions are used to prevent transmission by large-particle aerosols and do not require a negative-pressure room. Droplet precautions apply to dogs and cats with transmissible respiratory disease. Contact precautions are indicated for animals with infections that can be transmitted by direct contact with the patient or through fomite contact.

If it is known in advance that an animal with a suspected or known transmissible disease is to be seen at the hospital, arrangements should be made to have the pet owner take the animal from the parking area directly to an examination room, so that the animal does not contaminate the waiting area. After the animal has been examined, appropriate signage should be placed on the door of the examination room to prevent use until it has been properly cleaned and disinfected.

If hospitalization is required, animals with known or suspected transmissible disease must be admitted either to an isolation ward or to regular hospital cages with handling precautions, based on the pathogen suspected. Immediately after hospitalization, the name of the suspected or known pathogen should be posted on the cage or run, together with a handling precautions notice. Animals that require contact precautions should be placed in cages away from other animals in the ward and should not be moved from one cage to another, unless there is a medical need. Animals with transmissible respiratory disease should be placed in isolation and separated both horizontally and vertically from other patients by at least 4 feet. Gloves and a gown should be put on before the patient is handled, and then removed and disposed of immediately afterward. Hands should be washed after the gloves are removed. Additional items of personal protective equipment (masks, gowns, gloves, booties) may be required in some circumstances. Soiled linen and equipment should be handled, transported, and processed in a manner that prevents skin and mucous membrane exposures and contamination of clothing and that avoids transfer of microorganisms to other patients and environments. All equipment that contacts the patient (scales, examination tables, stethoscope heads, floor) should be cleaned and disinfected immediately after use. Medications and fluids from these patients should not be returned to the hospital pharmacy. When possible, personnel who handle these animals should not work with other immunosuppressed animals in the hospital, or they should work with the infectious disease cases last. If animals with contact precautions must be moved within the hospital, personnel should ensure that precautions are maintained throughout and that equipment and environmental surfaces that come into contact with the patient are properly disinfected and/or disposed of. The cleaning and bandaging of wounds infected with multidrug-resistant bacteria should be conducted in low-traffic areas that can be properly cleaned and disinfected.

The owners of dogs and cats that have transmissible diseases should be provided with general information regarding the risk of disease transmission to in-contact animals and people that includes the mode of transmission, duration of organism shedding, and if there are special implications for young children or other immunosuppressed individuals. If dogs and cats are diagnosed with a zoonotic disease, the owners should be notified without delay. The owners should be told to see their physicians if they become unwell or, in some circumstances, immediately, and to advise a physician of the potential exposure.


In contrast to human hospitals where patients can be more readily isolated in single-bed rooms or cubicles, isolation of veterinary patients can be more difficult because of the close proximity of one animal to another. Floor contamination with secretions and excretions can also occur more readily. Isolation rooms are available in many veterinary hospitals, but they may be poorly visible and/or accessible and may not provide access to an oxygen source or be amenable to intensive monitoring and care. For some animals (especially puppies and kittens) suspected to have a transmissible disease, housing in a general ward or ICU area with as much physical and procedural separation as possible, and with strict infection control practices, may be acceptable (if perhaps not optimal). Once a diagnosis is confirmed, the animal should be moved immediately to isolation whenever possible. Patients chosen for strict isolation vary based on the specific situation and facilities available, but suggestions are provided in Box 11-2.

Only the individuals directly involved in the care of the patient should enter isolation. Pet owners should not be allowed into the isolation ward. No equipment used outside isolation (pens, thermometers, stethoscopes, cell phones) should be brought into isolation. Laboratory coats should be removed, and personnel must put on protective wear such as a disposable gown, gloves, and booties when entering the isolation ward. Face protection may also be required, depending on the situation. A notice that outlines the required precautions should be posted on the door of isolation. Protective clothing should be removed before leaving isolation, and hands should be washed. Once a patient has been discharged, the room should be properly disinfected.

Handling of Potentially Infectious Materials and Waste

The risk of human infection from patient blood and body fluids in small animal hospitals is clearly lower than that in human hospitals. However, a number of zoonotic pathogens have the potential to be spread from dogs or cats to humans through contact with medical waste, and a number of emerging zoonotic infectious agents are bloodborne. Examples include Bartonella spp., Anaplasma phagocytophilum, Brucella spp., and hemoplasmas. Proper handling of blood and body fluids also has the potential to protect staff against as-yet-unrecognized zoonotic pathogens. Improper disposal of medical waste in veterinary hospitals risks injuring others who handle the waste and has the potential to result in serious penalties or fines.

Potentially contaminated waste should be disposed of in an approved plastic bag in a container labeled on all exposed sides with “biohazardous waste.” Blood-soaked materials, infected materials, and empty fluid bags should all be placed in biohazardous waste containers. Care should be taken not to contaminate the outside of the container during disposal. The lid of the biohazardous waste container must close properly. Blood and body fluids should be inactivated with an appropriate disinfectant (e.g., bleach or accelerated hydrogen peroxide) and allowed to stand for 10 minutes before disposal. Disposal regulations may vary depending on local laws, but liquid waste should not be disposed of into storm drains.

Specimens for laboratory testing that are collected from a patient with suspected zoonotic infectious diseases should be placed in an outer plastic bag, taking care not to contaminate the outside of the plastic bag, and labeled with an appropriate warning label. Fecal material should be picked up using a tongue depressor while wearing gloves, and placed in a sealed plastic cup and clearly labeled. Urine specimens should be submitted in a sealed container.

Sharps Handling

Sharps handling practices receive considerable attention in human medicine because of the risk of transmission of various bloodborne pathogens. Although the risks are less in veterinary medicine, significant injury or illness can follow sharps injuries, such as transmission of infectious agents from the patient, allergic or inflammatory reactions from exposure to medication, and inoculation of opportunistic pathogens from the injured person’s own skin microflora. Care should be taken to prevent injuries when needles, scalpels, and other sharp instruments are used, cleaned, or disposed of. Used needles should never be recapped, and they should not be removed from the barrel of a disposable syringe. Personnel should be instructed not to walk with uncapped needles and not to hold syringe or needle caps in the mouth. Used needles should not be carried in a pocket. Animals suspected of having an infectious disease that could be transmitted to humans through a needle-stick injury should be sedated before skin masses or peripheral lymph nodes are aspirated or venipuncture is performed. Contaminated sharps (slides, scalpel blades, broken glass, needles with attached syringes) must immediately be placed into an approved puncture-resistant sharps disposal biohazard container. Personnel who perform necropsy examinations should take care to use sharp knives in the proper manner and to avoid rushed situations. If a contaminated sharps injury occurs, medical attention should be sought immediately if necessary.

Hospital Cleaning, Disinfection, and Sterilization


Sterilization refers to complete elimination of all microbes, including bacterial spores, and is accomplished in hospital settings using processes such as pressurized steam, dry heat, ethylene oxide gas, or liquid chemicals.

Disinfection is the process that eliminates many or all microbes from inanimate objects, but not bacterial spores. Factors that influence the efficacy of disinfection include the type of microorganism present, their number, the amount and type of organic matter present, the presence of biofilms, and the porosity of the surface to be disinfected. Some disinfectants kill spores at high concentrations and with prolonged exposure times. These are known as chemical sterilants. At low concentrations and short contact times, chemical sterilants inactivate all microbes except large numbers of bacterial spores and are known as high-level disinfectants. Low-level disinfectants inactivate most vegetative bacteria, some fungi, and enveloped viruses, but not bacterial spores. Intermediate-level disinfectants inactivate mycobacteria, vegetative bacteria, most viruses, and most fungi (Tables 11-2 and 11-3).

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Jul 10, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on Infection Control Programs for Dogs and Cats

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