Airborne microorganisms in a rearing henhouse for layers during vaccination

Airborne microorganisms are proved regularly in livestock houses as a part of stable dust and its amount depends on housing conditions, the flow of air and the movement of material. Health of animals and farmers can be influenced in a negative way by these bioaerosols. In a rearing house for layers concentrations of various groups of airborne microorganisms were measured during vaccination by a veterinary and his three assistants. During the vaccination activities the concentrations of some airborne microorganisms increased by a factor of ten to the following medians of colony forming units (cfu) on used selective agars (cfu/m 3 ): 10 3 on MacConkey (36 °C), 10 3 on Dichloran-Glycerol (25 °C), 10 7 on Tryptone Soy (CaSo, 36 °C), 10 3 on Salmonella-Shigella (36 °C), 10 2 yeasts on Sabouraud (36 °C), and 10 2 on Campylobacter (36 °C). Thermophilic fungi were only grown on some of the used Maltextract agar dishes (45 °C) in concentrations near of the limit of detection. Some aerial samples were analysed for Chlamydia. Chlamydophila psittaci was not detected. Concentrations of airborne microorganisms in livestock houses depends not only on housing conditions but also on specific work procedures of farmers or on the activity of the animals.