The pathogens causing pneumonia are difficult to identify because a high quality specimen from the lower lung is difficult to obtain. A specimen collection device, named the PneumoniaCheck, was previously designed to collect aerosol specimens selectively from the lower lung generated during deep coughing to aid in the diagnosis of specific pathogens causing pneumonia. The device also includes several specially designed features to exclude oral contaminants from the sample, and a filter to collect the aerosolized pathogens. The objective of this thesis is to develop tests to verify the functionality of the device, called the Design Inputs. Nine verification tests were performed to demonstrate the ability to collect lower airway aerosols separate from upper airway aerosols, successful exclusion of oral contents, and capture of pathogens in the filter. Further, the PneumoniaCheck was tested for proper sampling of the lower airway aerosols during deep cough at a very low volumetric flow rate to simulate patients with severe restrictive lung disease and with mal-positioning to simulate incorrect patient placement. Verification testing of the PneumoniaCheck demonstrates effective separation of upper airway gas from the lower airway gas (p<0.0001) and exclusion of both liquid and viscous oral material (p<0.0001) from the collection chamber. Testing also demonstrated the selective sampling of the lower airway, even during low volumetric flow rates or incorrect positioning of the device. The complex shape of the PneumoniaCheck presents a manufacturing challenge. Making the device from a solid and then drilling out the tubes would be difficult because the outer channels do not align with the inner channel. Rapid prototyping, vacuum molding, and injection molding are all manufacturing options. Rapid prototyping is slow, and usually only economic for small numbers of parts. For vacuum molding or injection molding, the PneumoniaCheck would need to be cut in half and molded, and then the halves connected with fasteners, glued, or welded. Vacuum molding is inexpensive, but there would be a lip at the connection that may be uncomfortable for patients. If the lip is on the inside of the device, it may interrupt air flow through the device. Injection molding is inexpensive and fast. The PneumoniaCheck could be injection molded in halves, and then glued or sonically welded together. Injection molding would be an efficient and economical way to manufacture the device. Verification tests were developed and performed, and the results demonstrate that the PneumoniaCheck successfully collects lower airway aerosols separate from upper airway aerosols, excludes oral contents, and captures pathogens in the filter, even during non-ideal conditions. After considering three different manufacturing options, injection molding was recommended for the device.

Les éleveurs laitiers-bovins présentent une incidence plus élevée de symptômes respiratoires et de maladies broncho-pulmonaires que la population générale. Un facteur de risque important serait l’exposition professionnelle à divers aéro-contaminants d’origine biologique et chimique. Les déterminants professionnels de ces expositions et les effets biologiques des contaminants inhalés de manière répétée restent cependant mal connus. Dans ce contexte, les travaux réalisés au cours de cette thèse avaient pour objectifs i) de rechercher les déterminants professionnels de l’exposition aux bio-aérosols thoraciques (poussières organiques, endotoxines, bactéries et moisissures), à l’ammoniac et à l’acétaldéhyde, et ii) de caractériser les effets pro-inflammatoires des poussières thoraciques émises lors de la tâche de paillage mécanisé qui est connue pour induire une forte exposition aux bio-aérosols. Pour atteindre ces objectifs, nous avons réalisé une campagne de 112 mesures individuelles répétées dans 29 exploitations laitières d’élevage bovin localisées en Bretagne. Par l’utilisation de modèles multivariés à effets mixtes, nous montrons que l’exposition aux bio-aérosols est majoritairement induite par l’exécution de tâches liées à la distribution de litières et d’aliments (paille, foin, ensilage). L’exposition à l’ammoniac est fortement dépendante du nombre de vaches présentes dans l’exploitation et des temps passés en stabulation et en salle de traite. L’exposition à l’acétaldéhyde est dépendante de la taille de l’exploitation et des tâches liées à la distribution d’ensilage. Nos travaux soulignent également qu’une augmentation de la surface des ouvertures de la stabulation est associée à une réduction significative de l’exposition aux moisissures, à l’ammoniac et à l’acétaldéhyde. Enfin, notre étude montre que les poussières émises lors du paillage mécanisé ont (1) une taille leur permettant de se déposer majoritairement dans les régions trachéo-bronchiques, (2) une composition bactériologique et fongique complexe et (3) in vitro des effets pro-inflammatoires puissants induisant l’expression de TNF-α, d’IL-1β, d’IL-6 et d’IL-8 dans des macrophages humains. Au total, ces travaux de thèse ont permis d’identifier des activités professionnelles et des caractéristiques d’exploitations augmentant significativement les niveaux d’expositions des éleveurs laitiers-bovins à des contaminants chimiques et à des poussières organiques pouvant théoriquement se déposer dans les tissus bronchiques où sont censées se développer différentes maladies broncho-pulmonaires. Les modèles statistiques développés au cours de la thèse permettent dès à présent la reconstitution des expositions des éleveurs et pourront être utilisés dans de futures études épidémiologiques et dans l’élaboration de programmes de prévention. / Dairy farmers have an increased risk of lower airway diseases that is likely related to occupational exposures to airborne contaminants. Nevertheless, occupational determinants of dairy farmers’ exposures remain poorly documented and the biological effects of the contaminants chronically inhaled by farmers need to be fully characterized. In this context, the objectives of this PhD thesis were i) to identify the occupational determinants of exposure to thoracic bio-aerosols (organic dusts, endotoxins, bacteria and moulds), ammonia and acetaldehyde, and ii) to characterize the pro-inflammatory effects of thoracic dusts emitted during the mechanical spreading of straw bedding, a task well-known to generate inhalable dusts. To achieve these goals, we carried out a 112-repeated exposure measurement campaign on 29 dairy farms located in Britany. Using multivariate mixed-effect regression models, we have demonstrated that farmers’ exposures to bio-aerosols were mainly induced by tasks related to bedding material distribution and cow feeding (straw, hay, silage). Exposure levels to ammonia were highly dependent on cow numbers and times spent by the farmers in stable and milking parlour. Acetaldehyde exposure was modulated according to the farm size and times spent to distribute silage. Our work also highlighted that an increase of the area of wall opening significantly reduced exposure to mould, acetaldehyde and ammonia. Finally, our study showed that dusts emitted during mechanical straw spreading have (1) a size small enough to allow them to deposit in the tracheobronchial regions, (2) a complex bacterial and fungal composition, and (3) strong in vitro pro-inflammatory effects that induced TNF-α, IL-1β, IL-6 and IL-8 expression in human macrophages. In conclusion, these results have identified different dairy farm characteristics and occupational tasks that significantly increased the exposure levels to chemical contaminants and thoracic organic dusts. Statistical models built during this research project already allow reconstitution of dairy farmers’ exposure that may of use in future epidemiological studies and to develop new preventive measures.