Animal Safety Data Sheets and FAQ
Animal Allergies: FAQ (frequently asked questions)
In the United States, an estimated 40 – 50 million people currently suffer from allergies. Hypersensitivity to household pets is a common problem in the population as a whole, and in research settings allergies to laboratory animals (ALA) can become a serious concern. ALA affects approximately one out of every five people whose education or occupation requires significant exposure to laboratory animals.
Rats and rabbits are the most frequently implicated species, but mouse allergies are becoming more apparent as the number of mice utilized increases and the research projects using them require more direct handling (e.g., surgical manipulations, individual testing and identification, etc.). Cat and dog allergies may also be occupational if a research project includes those species, and it is possible to develop allergic reactions to most other species after chronic exposure, including hamsters and ferrets.
Although it is true that persons with very limited contact develop fewer problems, studies have shown that the problem of ALA can be just as severe in those handling animals for scientific purposes (research staff) as it is in those responsible for their primary care (caretaking staff).
A history of previous allergies (i.e., atopy) is not a guarantee that animal-related problems will develop, but some studies have found a correlation between pre-existing atopy and ALA.
The symptoms are generally evident after 6 – 24 months of exposure, but they may take years to develop and often become worst as years go by. Mild symptoms of ALA involve the eyes and nose (sneezing, runny nose, watery eyes; 80% of the cases) and/or the skin (itchy welts and rashes; 40% of the cases). Allergic responses to unrelated allergens can be additive, so “hay fever” or an associated occupational allergy (e.g., latex hypersensitivity) may cause ALA symptoms to worsen.
These minor problems will not typically go away if the exposure to the animal allergens does not change, and they can ultimately progress to the most serious manifestation of ALA, which is animal-related asthma. Asthma is a serious, potentially debilitating problem that is considered an end-stage lesion in the progression of ALA, and it will predictably affect a percentage of workers who ignore the earlier symptoms of rhinitis or conjunctivitis (runny eyes and nose). Asthma is estimated to affect 2% of all people using animals during their first year of exposure, and an additional 2% per year thereafter.
ALA can have serious consequences for affected personnel, not just in terms of personal health but in determining future career options. Studies have shown that about 50% of those with symptoms (or 9% of all workers) will eventually stop working with animals permanently of temporarily because of the discomfort involved with ALA. Many of these people can change career tracks or be re-assigned to non-animal duties within the same institution, but as many as 15% of affected workers will eventually quit their jobs because of ALA. Even after making a change, manifestations of asthma may not completely subside until 6 months or more after ending contact with the animals.
It was once thought that cat and dog allergies were provoked by dander or fur, but it is now known that the actual allergens are proteins in the saliva which are present on the skin and hair. In the case of ALA involving rodents the major allergens are low-molecular-weight proteins excreted in the urine. These proteins adhere to the skin and hair and can also be found in soiled bedding and distributed as airborne contamination in rooms where animals are housed or manipulated.
There are three general approaches to the treatment of allergies: avoidance of the allergen (through environmental control methods), medication to relieve symptoms, and immunologic desensitization (allergy shots). Medication can provide relief, but a few things should be kept in mind. First, although there are over-the-counter drugs which can give temporary symptomatic relief, it is best to seek the advice of a physician before self-prescribing because these drugs can mask the warning signs of developing asthma and cause drowsiness. Second, if an antihistamine is used, best results will be obtained only if the drug is taken PRIOR to allergen exposure not after the symptoms begin. In addition, other types of anti-allergy drugs that do not include drowsiness are now available by prescription if necessary. Standard allergy shots (immuno-therapy) to reduce allergic sensitivity to cats/dogs have improved in recent years and may be considered for select individuals.
Allergen avoidance is the only sure way to deal with ALA, but this can be a problem if an individual’s choice of occupation involves animals. If complete avoidance is impossible, it is critical that exposure be minimized as much as possible. The good news is that there are many people with ALA who are able to continue to work with animals by taking some simple precautions. The use of personal protective equipment (PPE) should include the use of a tight-fitting mask, gloves, and long-sleeved lab coat or other dedicated uniform at all times when working with animals. In some cases a respirator or a filtered-air supply face mask may be warranted. Users can take advantage of filter-topped cages (if applicable in facility) to contain allergens when animals are transported or held, and an understanding of the proper use of the different types of ventilated workstations which may be present in laboratories and/or the animal facility will help minimize aerosol exposure when cages are opened. Irritant chemicals can worsen airborne allergy symptoms, so persons with ALA should try to avoid unnecessary exposure to irritants such as dust, tobacco smoke, and air pollution. If you are experiencing symptoms of ALA, specialized medical professionals are available to help evaluate and treat your conditions.
It is important to stress that procedures to minimize allergen contact (such as those listed above) should be followed by all exposed persons even if ALA symptoms are not present, because this may prevent the development of clinical signs or at least greatly slow the progression of ALA.
Current federal guidelines require that all personnel beginning to work with animals be given information regarding ALA and the precautions that should be taken. ALA should be treated like any other occupational health hazard, and personnel should notify their supervisor of known or potential work-related allergies. Clear procedures should be established in each animal use/care facility for reporting all allergic reactions in the same way that accidents, bites, and scratches are reported.