Follow-up study Livestock farming and the health of neighbouring residents (VGO-III)
People who live in the vicinity of a goat farm have a higher chance of developing pneumonia. That was demonstrated by the study “Livestock farming and the health of neighbouring residents (VGO)”, which was carried out in Oost-Brabant and Noord-Limburg. The possible causes of this are still not known. On behalf of the Ministry of Health, Welfare and Sport and the Ministry of Economic Affairs and Climate Policy, IRAS (Utrecht University), RIVM, Wageningen Bioveterinary Research (Wageningen University and Research) and NIVEL have started a follow-up study (VGO-III).
Previous VGO studies revealed that there is an increased risk of developing pneumonia within a 1km radius of poultry farms. The increased risk of developing pneumonia near a goat farm has, on average, a greater range: about 2 km. Living in the vicinity of poultry and goat farms accounts for a maximum of 10 to 20% of all cases of pneumonia in the region covered by the VGO study. In total, this concerns about 150 to 200 cases of pneumonia in the VGO study population (about 100,000 people).
Does particulate matter play a role?
It is not known what causes the increased risk of developing pneumonia. For poultry, it has been suggested that exposure to particulate matter and the endotoxins that occur in it can lead to a shift in the microbiome of the respiratory organ. Furthermore, such exposure can also exacerbate an existing respiratory condition, whether it is latent or not. In the case of a weakened immune system, certain human pathogens can then give rise to pneumonia.
‘It is vital for farmers and neighbouring residents that we find out what causes the increased incidence of pneumonia’, says Lidwien Smit, coordinator of the VGO-studies and Associate Professor at IRAS. ‘Once the cause is known, we can start developing effective preventive measures.’
Not due to Q fever
The increased risk of developing pneumonia in the vicinity of goat farms is no longer correlated with the occurrence of Q fever. In recent years, the incidence of pneumonia in the vicinity of goat farms has been the same, irrespective of whether Q fever was present on those farms during the Q fever outbreak of 2007-2010. It is also unlikely that the incidence is related to particulate matter levels in the vicinity of goat farms (PM10), as these are usually quite low (less than 0.4 mg/m³ in barns) and are significantly lower levels than in the barns of poultry farms. Nevertheless, a possible role of particulate matter cannot be entirely excluded.
Manure storage and management
Manure storage and management on farms could also play a role. These factors were not included in previous VGO studies. Since the outbreak of Q fever, the deep litter barns in which the manure is stored may only be emptied after 30 days. The conversion of manure heaps could be associated with high particulate matter and microbial emissions. Research outside of the Netherlands has revealed that emissions from compost heaps can result in health risks. In summary, more detailed research is needed into the increased risks of developing pneumonia so that more effective preventative measures can be taken. The VGO-III study will hopefully be able to provide answers to all of these questions.