Comparison of Indoor and Outdoor Bioaerosols in Poultry Farming

Intensive poultry production, implying large densities of animals in small areas, is a significant source of air pollution which may constitute a considerable health hazard to the birds, farmers and those living in the proximity of the farm (Lonc & Plewa, 2009). On the other hand, the spread of bioaerosols on the outside of animal housing may result in local or even more extensive environmental pollution (Bakutis et al., 2004). Under commercial production the airborne particles will contain a mixture of biological material from a range of sources. The chickens produce large amounts of dust as a result of epithelial desquamation, as well as from feed, manure, faeces and litter (Matković et al., 2009). This dust consists of a variety of airborne particles of biological origin, i.e. bacteria, fungi, endotoxins (lipopolysaccharide, LPS) of Gram-negative bacteria, 1.3-beta-glucan of fungi, fungal spores and mycelium fragments. Hence, a more descriptive term for these airborne particles is bioaerosol in which the microorganisms can occur either as liquid droplets or as dry particles [Dutkiewicz, 1987; Matković et al., 2009; Nevalainen, 2007]. In specific conditions, bioaerosols may show pathogenic, toxic or allergy-causing effects. The particles in a bioaerosol are generally 0.3 to 100 μm in diameter; however, the respirable size fraction of 1 to 10 μm is of primary concern. Bioaerosols, ranging in size from 1.0 to 5.0 μm, generally remain in the air, whereas larger particles are deposited on surfaces (Srikanth et al., 2008). Bioaerosol may contain representatives of Gram-positive bacteria: Corynebacterium, Staphyloccocus, Streptococcus, Micrococcus, Pantoea and Sarcina (Siemiński, 2001). Their presence in large numbers may present a significant immunological challenge to the human respiratory system. In dust are suspended also endotoxins (lipopolysaccharide complex LPS) associated with the outer membrane of Gram-negative pathogens, such as Escherichia coli, Salmonella, Shigella, Pseudomonas, Neisseria and Haemophilus influenzae. LPS is composed of two major parts, the hydrophobic lipid A and the hydrophilic polysaccharide part (commonly called the "O" region). Most biological effects of LPS are due to the lipid A part, however O-region plays an important role in effective colonisation of host tissues. Inhalation of organic dust contaminated by endotoxins may cause chronic bronchitis and inflammatory reaction in the lungs (Bakutis et al., 2004, Schierl et al., 2007, Pomorska et al., 2009).