Occupational asthma due to exposure to animal proteins in animal handlers

Background Occupational or work-related asthma has been found to be common. Animal handlers ranging from laboratory researchers, veterinarians, to food processing workers are exposed to animal protein allergens which cause asthma with symptoms of cough, wheezing and chest tightness. These allergens, from animal body or body fluids, can be carried on in the air for prolonged periods. Method This review used articles from PubMed searched with the terms “animal proteins and occupational asthma” with limit as “work published in the last 10 years” (1970-2009). Result Several studies put the incidence rate of occupational asthma amongst laboratory researchers to about 10 – 21%. In a 12-year cohort study of workers exposed to laboratory animals, incidence of asthma was higher for workers with long hours of exposure to tasks requiring working with animal cages or many animals. Most allergens are “lipocalins”, a group of glycoproteins. A worker with previous occupational allergy to lipocalins of pig showed specific IgE to chicken allergen few minutes after exposure to chicken. Studies on genetic basis for asthma are mostly inconclusive or not replicable. Conclusion Development of occupational asthma is associated with prolonged exposure to animal at work place and with high level of lipocalins or animal protein in the work environment. Allergens are similar in structure and as a result cross-reactions occur. There is need for a multidisciplinary collaboration in defining the gene-environment basis of occupational asthma so that individuals predisposed to asthma are identified and control instituted.