Pneumonia is more common among people living in areas in The Netherlands with many livestock farms. The additional risk of pneumonia is higher if people live within 2000 metres of a goat farm. Bacteria that may explain the extra pneumonia cases have been identified in samples taken from the stables of goat farms. These bacteria may explain the extra pneumonia cases because the same bacteria were also found in the outdoor air samples close to goat farms and/or in people living near these farms. These are results from VGO-III, the latest research on Livestock Farming and Residents' Health, a collaboration between RIVM, Utrecht University, Wageningen University & Research and Nivel.
Researchers from Wageningen University & Research (WUR) conducted the study on goat farms, in collaboration with researchers from Utrecht University (UU). More than 30 different bacteria were found in the stable air of goat farms that can cause pneumonia (CAP) in humans. Of these bacteria, 23 were also found in patients, residents, goat farmers and/or in the outdoor air around goat farms.
Previous research (VGO-I and -II) showed that in areas with many livestock farms, pneumonia occurs more often. VGO-III confirms this and also that especially residents close to goat farms are at higher risk of pneumonia. This risk is greatest for people living closest to a goat farm.
Sub-study
VGO-III consisted of several sub-studies, which looked from different angles at which pathogens could be the cause of the extra pneumonia cases. Wageningen Bioveterinary Research and Wageningen Livestock Research (both part of WUR), in collaboration with the Institute for Risk Assessment Sciences (IRAS) of Utrecht University, investigated pathogens on goat farms. This research took place in close coordination with sub-studies among goat farmers and in the outdoor air around goat farms.
Analysis
The WUR researchers analysed samples taken from goats, manure, bedding and stable air on 16 different goat farms. More than 30 different bacteria known as a cause of pneumonia in humans were found in the stable air. Many of the bacteria found in the stable air were found to originate from the mixture of farmyard manure and bedding as used on most goat farms. The researchers found no relationship(s) between the presence of the pathogens on goat farms and differences in farm factors on the 16 farms. Examples of farm factors include ventilation system and farm size.
Pneumonia
Of the 30 bacteria found in stable air, many were also found in the outdoor air around goat farms, air measurements at nine locations in the Dutch provinces of Noord-Brabant and Limburg.
Combined with the results of sub-studies among goat farmers, patients and residents carried out by the other partners within VGO-III, 23 bacteria were identified that may explain the higher incidence of pneumonia near goat farms. It is difficult to prove that the bacteria from goat farms are the direct cause of the extra pneumonia cases in people around goat farms.
Recommendation
Following the findings in VGO-III, the project partners recommend investigating ways to reduce the amount of potential pathogens in stable and ambient air from goat farms in order to lower the exposure of nearby residents to pathogens.
