Occupational and Environmental Risks Caused by Bio-Aerosols in and from Farm Animal Houses
The air in modern animal production systems contains a large variety of aerial pollutants which are widely recognised as detrimental for the respiratory health of animals kept in these facilities and the work force working regularly in this atmosphere. Primary and opportunistic microbial pathogens may cause directly infectious and allergic diseases in farm animals, and chronic exposure to some types of aerial pollutants may exacerbate multi-factorial environmental diseases. There are, however, few international field surveys paying attention to the health of the farmers and the farm personnel working in animal houses, and to the spread of pathogens from farm buildings. Studies reveal that up to 20 % of farmers and farm workers complain about symptoms of respiratory affections such as coughing, sputum, wheezing and others. Some develop asthma, others develop diseases which are described as e.g. ODTS (organic dust toxic syndrome). There are indications that various pathogens can survive in an air-borne state for several minutes and can be distributed over long distances in the ambient air of farms, e.g. foot and mouth virus can travel aerially more than 50 km. In a recent study it was shown that Staphylococcae can be found in significant concentrations (4000 cfu/m³) in about 500 m down wind of broiler barns. A future-oriented sustainable farm animal production should enhance - beside the topics of animal welfare, consumer protection and economy - also standards to improve occupational health and to prevent or reduce the spread of pathogens via the air.