Community-acquired pneumonia and proximity to poultry and goat farming in the Netherlands:: the evidence and potential causal leads

Abstract

Previous studies in the Netherlands from the ‘Livestock Farming and Neighboring Residents’ Health’ (In Dutch: VGO) project have shown that people living near goat and/or poultry farms have a higher risk of pneumonia. The VGO-III research program investigates human health, ambient air, goats, and their farm environment to gain insight into the potential causes of the increased pneumonia risk around goat farms. In doing so, VGO-III adopts a One Health approach recognizing that the health of humans, animals and the environment are interconnected. The aim of this thesis, which was part of VGO-III, was to explore which pathogens may be involved in the increased pneumonia risk around goat farms and to further increase our understanding of this epidemiological association. This thesis combined different types of studies, such as nationwide cross-sectional studies, a scientific literature review, and cross-sectional studies in primary and secondary care. The nationwide analyses showed that living close to poultry farms, but not goat farms, was associated with both the use of antibiotics that are prescribed for respiratory infections and pneumonia hospitalization. Still, as the increased pneumonia risk around goat farms has been found over a period of more than a decade, further in-depth etiological research is needed as presented in this thesis. The routinely collected laboratory data of pneumonia patients admitted to the hospital could not give an explanation of the micro-organisms potentially involved in the increased pneumonia risk around goat farms. However, the literature review yielded nearly one hundred micro-organisms found in goats that can cause pneumonia in humans. Overall, the work presented in this thesis gives direction to further studies within the VGO-III research program. Furthermore, the design of the VGO-III sub-study among pneumonia patients in primary care is described. Ultimately, integrated results from all VGO-III sub-studies should help clarify potential causes and provide guidance for intervention strategies to reduce pneumonia incidence around goat farms.