Animal work should comply with the Australian Code for the Care and Use of Animals for Scientific Purposes (National Health and Medical Research Council).

All work on infected animals should be carried out under the physical containment conditions equivalent to the risk group of the microorganisms present (refer to Standards Australia AS/NZS 2243.3 - Safety in laboratories, Part 3 - Microbiology). The physical containment levels for work with infectious and transgenic animals follow the animal containment levels as per Office of the Gene Technology Regulator (OGTR) requirements of PC2, PC3 or PC4 as appropriate for the pathogen involved.

Details of the requirements for animal houses, especially for infective and transgenic animals may be found in AS/NZS 2243.3 and in the OGTR Handbook.

In many animal-holding areas, noxious odours, particularly ammonia, are present. Engineering controls should be in place to keep these levels compatible with the health and comfort of workers and the animals. The adequacy of the ventilation system, the design, construction and placement of cages and containers, the numbers of animals housed, the effectiveness of cleaning, and the frequency of bedding changes will all influence the level of odours and allergens such as fibres and animal dander.

Air exchanges within the animal rooms, temperature, humidity, light and noise levels should be maintained within limits compatible with the health and well being of both workers and animals.

Manual handling is an integral part of animal house work so care is required to minimise the risk of muscoluskeletal injury. Ergonomic assessment of routine work procedures will assist in this regard (contact UWA Safety and Health for assistance).

All persons involved in the study, handling and care of animals should receive appropriate induction training and information regarding standard work practices, potential hazards and how to deal with them. Written Standard Operating Procedures (SOPs) should include the demarcation and restrictions applying to different areas and animals as well as the routine procedures applicable to each. New workers and researchers should be supervised by animal care staff until they have demonstrated their ability to work with the animals without damage or stress to the animal itself and to themselves.

Hazards for persons using and handling laboratory animals may arise from a variety of sources, including viruses, bacteria, fungi, parasites, ionising and non-ionising radiation, hazardous substances, toxins, carcinogens, allergens, recombinant DNA techniques, anaesthetic gases and physical injuries.

Prior to any studies being carried out, a risk assessment should be performed and controls put in place to contain hazardous agents and to plan for "worst case" scenarios and emergencies.

The hazards associated with handling animals can be loosely placed in three major categories.

First, physical injuries occur from bites and scratches, especially from rodents, rabbits, dogs and cats. The key to prevention of these types of injuries is proper training of research personnel by the animal care staff or other qualified individuals. Laboratory animals are sometimes unpredictable in their nature and response, and any bite, scratch or similar injury should be reported as soon as practicable to the supervisor of the area. Medical advice and subsequent supervision may be needed if an infected animal inflicted the injury.

Secondly, the possibility of zoonotic diseases must always be considered. Zoonotic diseases are those that can be transmitted from animals to humans. Although zoonotic diseases are not common, the prevention, detection, and eradication of zoonotic diseases from the animal facility are a primary concern of the entire animal care staff. Remember that tissues as well as the animals can transmit zoonotic diseases.

Thirdly, there are serious allergic hazards associated with breathing or contacting animal dander or urine allergens (among others). The safest policy is to reduce exposure by wearing protective clothing (such as facemasks, gloves, and a lab coat) when handling animals.

Another hazard, which requires careful attention, is the use of anaesthetic agents.

Physical injuries

When handling laboratory animals, gloves should be worn, adequate washing facilities should be provided and prophylactic immunisation against tetanus is strongly recommended.

During dissections and post-mortem examinations, gloves, aprons (preferably disposable) and safety glasses or goggles should be worn. It may be also necessary to consider respiratory protection. Penetration of organisms through the skin, especially from accidental self-inoculation and contact with ecto-parasites is a relatively common source of infection. Spillage trays and containers for used instruments should be provided.

The use of restraint devices is sometimes necessary for the welfare of the animals and the safety of persons handling the animals. These devices should only be used to the minimum extent and for the minimum period required to accomplish the task.

All post mortems on infected animals should be carried out under the physical containment conditions equivalent to the risk group of the microorganisms present. Refer to AS/NZS 2243.3 for risk categories for microorganisms.

Zoonotic diseases

Although humans usually are not susceptible to infectious diseases suffered by animals, there are some important exceptions. Infections of animals may, on some occasions, produce significant diseases in humans even when the animals themselves show little if any sign of illness. A bacterium in the normal flora of a healthy animal may cause a serious disorder in a person exposed to it because the animal has developed "resistance" to these microorganisms, whereas humans with no previous exposure to the agent lack this protective immunity. Therefore, one should always be aware of possible consequences when working with each species of animals, and take precautions to minimise the risk of infection.

Q-fever arises from infected sheep, cattle, goats, rodents, marsupials, fowls and their ticks. It is caused by the ricksettial agent Coxiella burnetii. Onset of Q-fever is usually abrupt 2 to 3 weeks following exposure with symptoms of headache, shivering, weakness, severe sweating, dry cough, joint and muscle pains, loss of appetite, vomiting, shortness of breath, nose bleeds and sometimes intolerance of light. Antibiotic treatment is required. Vaccination against Q-fever is advisable for persons working in or frequently visiting abattoirs, large milk handling plants; handling wool, hides, bones or entrails from cattle, sheep or goats; or working with pregnant cattle, sheep or goats.

In the event that a person becomes ill with a fever or some other sign of infection, it is important that they let their treating doctor know that they work with animals.

There are some common sense steps that can be taken to lessen the risk of infection in general. These include not eating, drinking, or applying cosmetics or contact lenses around animals or animal care areas, wearing gloves when handling animals or their tissues, taking care not to rub the face with contaminated hands or gloves, and hand washing after each animal contact.

Persons working with laboratory animals can protect themselves against accidental self inoculation by wearing gloves, substituting manually operated pipettes for needles and syringes, taking enough time to give injections properly, anaesthetising animals prior to inoculation with infectious agents, and using a two person team to inoculate animals.

Do not recap the needles! Instead, discard them promptly in a biohazard "sharps" container. Should you accidentally prick yourself with a needle or find a discarded needle, please see the University's Procedure for needle and syringe disposal. For procedures such as necropsies, bedding changes, and tissue and fluid samplings physical containment devices such as biological safety cabinets, full-face respirators or other personal safety equipment should be used as indicated.

The scope of possible zoonotic infections is quite large and only a few examples will be described here. However, all personnel should be aware that laboratory animals are sources of potent allergens to sensitised persons.

Working with rodents or rabbits

In working with rodents (rats and mice) or rabbits, development of allergies to these species is probably the most common health hazard. Limiting exposure to soiled bedding and the use of gloves and mask may help. The potential for zoonotic disease is greatly reduced due to the high quality of animals available through suppliers today.

Working with dogs and cats

In working with dogs and cats, the risk of transmitted disease is high because most of these animals are purchased from sources that do not have disease control programs in place.

Toxoplasma is an infectious agent found primarily in cat faeces. It can infect the unborn baby in women exposed during pregnancy who do not already have immunity to the agent. Asymptomatic toxoplasma infection is common before childbearing years and many women have elevated antibody levels indicative of immunity. To help assess the level of immunity against this agent, serum samples can be tested prior to pregnancy. Cat faeces should be avoided and gloves should be worn when working in areas potentially contaminated with cat faeces. Thorough hand washing after handling any potential source of infection is also necessary.

Working with sheep

It is now known that the Q-fever organism is shed abundantly from the placental membranes of sheep. This route of exposure has been the cause of recent cases of Q fever pneumonia and other associated symptoms in laboratory workers.

Personnel working where exposure is possible should take extra precautions. Gloves, masks, and protective clothing are recommended for individuals working with pregnant sheep. Infected persons can be effectively treated. Q fever vaccinations are available.

Contagious ecthyma ("orf") from the mouth of an infected sheep can be transmitted to humans causing focal skin lesions on the hands.

Asthma and allergies

In the January 1998 publication by the US National Institute for Occupational Safety and Health (NIOSH), Preventing Asthma in Animal Handlers, several strategies for preventing exposure to animal allergens are discussed. Animal-related asthma is the immune system's response to allergens including animal dander, scales, fur, body wastes and saliva. Workers including laboratory animal workers, veterinarians, veterinary technicians, livestock workers, garment workers, and horse handlers are all at risk of developing work-related allergy symptoms.

Workers who show signs of allergies previous to employment are more likely to develop animal-induced asthma. Most reactions in technicians handling animals are due to exposures to small animals (rodents) on contact during feeding, cleaning, dosing, sacrifice, surgery, and body fluid collection. Most allergens are found in the urine of rats, and the urine, saliva, and pelts of guinea pigs.

Symptoms of mild reaction include sneezing and runny nose. More serious reactions include cough, chest tightness, wheezing, or shortness of breath. In sensitised individuals the reaction may be immediate or delayed 2 to 8 hours. Occupational asthma without nasal symptoms is uncommon. On developing skin hives, nasal, eye and throat symptoms, usually 50% of workers will go on to develop asthma.

Workers who report symptoms of work-related asthma should be medically monitored for early intervention. Without removal from exposure to allergens, affected workers may develop an irreversible disease. A worker who has severe or life-threatening allergic reactions should be strongly advised to change jobs, since no prevention strategy is completely effective.

Preventing exposure Animal handlers should take steps to protect themselves from exposure to animals and animal products. These steps include:

• performing animal manipulations within ventilated hoods or safety cabinets when possible
• avoiding wearing street clothes while working with animals, or as minimum protection gloves and lab coats should be worn
• leaving work clothes at the workplace to avoid potential exposure problems for family members
• keeping cages and animal areas clean
• reducing skin contact with animal products such as dander, serum and urine by using gloves, lab coats, and approved particulate respirators with face shields
• training workers in recognising the signs and symptoms of allergic reactions and sensitisation may prevent further asthma development.

Prevention of exposure includes several engineering and work practice controls such as, the following:

• modification of ventilation and filtration systems by increasing the ventilation rate and humidity in the animal housing areas
• ventilating animal-housing and handling areas separately from the rest of the facility
• directing airflow away from workers and toward the backs of the animal cages, and
• installing ventilated animal cage racks or filter-top animal cages
• decreasing animal density (number of animals per cubic metre of room volume)
• keeping cages and animal areas clean
• using absorbent pads for bedding - if these are not available, use corncob bedding instead of sawdust bedding
• using an animal species or sex that is known to be less allergenic than others
• providing protective equipment for animal handlers: gloves, lab coats, and approved particulate respirators with face shields
• providing training to educate workers about animal allergies and steps for risk reduction
• providing health monitoring and appropriate counselling and medical follow-up for workers who have become sensitised or have developed allergy symptoms.

The following are examples of actual case reports as recorded by NIOSH:

Example 1 - exposure to laboratory rats

A 21-year-old female worker at a pharmaceutical company prepared rats for experiments. She had no prior respiratory illnesses, but she had a family history of allergies. Three months after she started working, the worker noted hives on her forearms and hands. Her symptoms worsened until every direct contact with rats produced hives. Wearing gloves alleviated the problem, but she could not perform her work adequately when using them.

The worker then began to suffer episodes of sneezing, nasal drainage, watery eyes, and chest tightness. She was transferred to another department, where her symptoms ceased. However, they recurred if she entered a room with rats or where rats had previously been housed. The worker had positive skin tests to animal dander and to rat hair. She also had elevated antibodies (IgE) to various rat proteins.

Example 2 - exposure to rabbits

A physician had been working on a research project involving rabbits for several years. He had an allergy to cats but not to dust mites or other common allergens. The physician developed progressively worsening nasal congestion and eye irritation.

During work with a rabbit, he received an accidental needlestick. Within 15 minutes, the physician noted progressive itching, swelling of the face, hives, throat tightness, and inability to speak. He was admitted to the hospital where he received emergency treatment for anaphylactic shock. His symptoms stabilised over a 5-hour period. Blood samples showed increased antibodies (lgE) to cat dander and rabbit epithelium. The antibodies to rabbit epithelium declined over the 6-month period after he left the job that involved rabbit contact.

Example 3 - exposure to various animals

Thirty-eight students were examined during their first year of training as laboratory technicians (median age was 21 years). They were re-examined after working with various laboratory animals (primarily rats, mice, and rabbits) for an average of 18 months. At that time, nine students (24%) had developed allergies to laboratory animals. Symptoms included nasal and eye irritation in seven students, skin rashes in four, and chest problems in three.

Of the nine students with animal allergies, seven had reactions to rat or mouse antigen in skin-prick tests, and eight showed asthma like reactions during lung testing.

Anaesthetic agents

Anaesthetic agents used in laboratory animals may also pose potential hazards to workers. These agents should be treated as hazardous chemicals with a risk assessment carried out of the chemical agents and the operations involved. A Material Safety Data Sheet (MSDS) should be available and understood by all relevant workers.

In addition to worker safety, animal welfare is a paramount consideration in selecting the anaesthetic for each particular species of animal and each operation carried out. The Animal Ethics Committee should always be consulted early in the planning stages and prior to a decision regarding which type of anaesthetic to use.

Learn more about the health monitoring procedures.

• Australian and New Zealand Council for the Care of Animals in Research and Teaching
• Office of Gene Technology Regulator (OGTR) Refer to Publication, Handbook
• Institutional Animal Care and Use Committee
• National Health and Medical Research Council (NHMRC), Australian Code for the Care and Use of Animals for Scientific Purposes, 8th Ed, 2013, NHMRC, Canberra
• National Institute of Occupational Safety and Health, NIOSH Alert Preventing Asthma in Animal Handlers, the Institute, 1998.
• Standards Australia, AS/NZS 2243.3- Safety in laboratories Part 3 Microbiology

UWA Safety and Health wishes to acknowledge CCH Australia: Laboratory Safety Manual for information provided within these procedures