Methods of housing and care of laboratory animals, and the careful control of sources of supply of animals, diet, bedding and other items used in an animal facility have greatly reduced the risk of exposure of staff to zoonotic diseases. Zoonoses are diseases of animals that are transmissible to man, and some can occur in laboratory species (Hankenson et al, 20031).
Since it is routine practice to conduct health surveillance of laboratory rodent colonies, potentially serious infectious agents such as Leptospirosis and Salmonella are virtually unknown in laboratory rodents in the UK. However, if working with wild rodents, these are potentially serious risks, and a careful risk assessment should be conducted prior to working with such animals.
In most cases, simple measures such as not eating or drinking in animal areas, wearing appropriate protective clothing, and cleaning and decontaminating work surfaces after use (using the disinfectants and cleaning procedures recommended in your facility) will greatly reduce the risk of contracting these infections.
Adoption of appropriate methods of handling and restraint greatly reduce the risk of being bitten or injured by laboratory animals (see Minor Procedures without Anaesthesia). Modern housing and husbandry can also reduce the risk of developing allergies to laboratory animals. This is a particular issue when working with laboratory rodents, since exposure to their urine, fur, or other materials can result in the development of allergies.
Laboratory Animal Allergy (LAA)
Laboratory Animal Allergy (LAA) can cause a range of symptoms including rhinitis, conjunctivitis, skin irritation, and asthma. Allergies often develop slowly but can occur without any previous indication that sensitisation has occurred. If you experience any of these symptoms when working in an area that could contain allergens, leave the area immediately and seek medical advice. If symptoms develop later, be aware that they could be due to exposure to animals, and draw this to the attention of your doctor.
The majority of cases of LAA are due to working with rodents, rabbits or locusts, and the condition is classified as an occupational disease in the UK. If you develop an allergy, you should report this to your employer and they must notify the Health & Safety Executive under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (1995) – RIDDOR.
The main sources of allergenic material have been identified as rat and mouse urine, fur and saliva, as well as guinea pig and rabbit fur. The main route of exposure is by the inhalation or deposition of the airborne particles onto mucosal surfaces. Control measures, therefore, aim to reduce the concentration of the airborne allergens inhaled by staff. These include reducing exposure by housing animals in IVC caging, using clean-air stations when opening cages to carry out procedures or for routine husbandry, and optimising airflow patterns in animal holding and procedure rooms.
Personal Protective Equipment (PPE) can be used to reduce exposure, and practices vary in different facilities. As a minimum, a lab coat, gloves and a facemask should be worn when working with animals. These must be removed when leaving the area, to avoid the transfer of allergens elsewhere in the building. Use of air showers when exiting animal holding areas can also be valuable in reducing the spread of allergens.
The early detection of LAA will enable further precautionary measures to be adopted if required. If symptoms cannot be alleviated then you should avoid further exposure to the animals that cause your symptoms (Alderman et al, 20182).