Preventing Asthma in Animal Handlers


January 1998
DHHS (NIOSH) Publication Number 97-116
cover of NIOSH Alert 97-116

Case Reports

Case 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 [DeGroot and Messerschmidt 1984].

Case 2 – Exposure to Rabbits

A 32-year-old physician had been working on a research project involving rabbits for 2 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 stabilized over a 5-hour period. Blood samples showed increased antibodies (IgE) 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 [Watt and McSharry 1996].

Case 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 [Renström et al. 1995].


Asthma and other respiratory illnesses may develop in persons whose work requires close contact with animals and animal products. Asthma in animal handlers can result in respiratory symptoms that are severe and persistent. These symptoms can lead to permanent disability or require a career change. Workers at risk for developing symptoms should be advised to take precautions to avoid or minimize exposures. Several methods for reducing exposures and decreasing the risk of sensitization are available to employers and workers. Medical monitoring of exposed workers and remedial actions for workers with symptoms can further reduce the risk of permanent adverse health effects. With timely and appropriate action, many cases of animal-related asthma can be prevented.

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