Occupational bio-aerosol exposure in veterinary medicine: a comprehensive assessment of exposure and exploration of bio-aerosol related health effects

Studies showed that workers handling animals especially in livestock farms (e.g. pig, cow, and poultry) are likely exposed to high levels of bio-aerosols. Working with animals during veterinary practice has great similarities with livestock farming because veterinary populations spent a considerable amount of their time in stables or clinics in close contact with animals. Thus, exposure to bio-aerosols during veterinary practice seems likely, but detailed and comprehensive studies on bio-aerosol exposure are lacking. A few studies also demonstrated that veterinary populations are probably at risk for the development of allergic and non-allergic respiratory effects, but associated bio-aerosol exposure is largely unknown. The main purpose of this thesis was to comprehensively investigate exposure levels of inhalable dust, endotoxin, β(1→3)-glucans, and animal specific allergens among veterinarians, veterinary students, and animal caretakers (workers) in diverse veterinary clinics, as well as to explore exposure determinants. In addition, the presence of sensitization/allergy and respiratory symptoms among veterinary medicine students, which might be related to bio-aerosol exposure, was studied. Results showed that substantial endotoxin and β(1→3)-glucan exposure levels occur in veterinary clinics especially when handling farm animals and horses. Endotoxin exposure levels were much lower in the companion animal clinic. Exposure levels when handling farm animals or horses are comparable to those levels observed in farming which have been associated with respiratory health effects. Animal specific allergen exposure showed to be measurable in companion animal clinics and dairy barns. Veterinary medicine students appeared at increased risk of developing respiratory symptoms, particularly those working with farm animals and horses. This is in line with studies among pig farmers, exposed to similar environments as veterinarians, which strongly confirms that bio-aerosol exposed veterinary populations are at an increased risk of developing respiratory diseases. Exposure to animal allergens during veterinary practice is probably causing allergic inflammation, characterized by IgE-mediated reactions to animal allergens. In conclusion, veterinary populations are likely to be exposed to elevated levels of microbial bio-aerosols such as endotoxins, β(1→3)-glucans, and some specific animal allergens. Exposure to these agents in similar settings like livestock farmers and laboratory animal workers were previously associated with allergic and non-allergic respiratory effects, suggesting that similar health effects can occur in veterinary populations