A comprehensive review of levels and determinants of personal exposure to dust and endotoxin in livestock farming

Abstract

The respiratory health effects of livestock farming have been on debate for more than three decades. Endotoxin-contaminated organic dusts are considered as the most important respiratory hazards within livestock environments. A comprehensive review of the knowledge from studies assessing the exposure status of livestock farmers is still to be published. The present study reviews research published within the last 30 years on personal exposure of livestock farmers to organic dust and endotoxin, focusing on studies on pig, poultry and cattle farmers. Applied measurement methods and reported levels of personal exposure for the total, inhalable and respirable fractions are summarized and discussed, with emphasis on the intensity of exposure and the size and distribution of the reported exposure variability. In addition, available evidence on potential determinants of personal exposure to dust and endotoxin among these farmers are documented and discussed, taking results from exposure determinant studies using stationary sampling approaches into consideration. Research needs are addressed from an epidemiological and industrial hygiene perspective. Published studies have been heterogeneous in design, and applied methodologies and results were frequently inadequately reported. Despite these limitations and the presence of an enormous variability in personal exposure to dust and endotoxin, no clear downward trends in exposure with time were observed, suggesting that working environments within stables remains largely uncontrolled. Exposure control and prevention strategies for livestock farmers are urgently required. These should focus on the development of novel and improved methods of controlling dust and endotoxin exposure within stables based on the currently available knowledge on determinants of exposure.

The effect of organic dust exposure on long-term change in lung function: a systematic review and meta-analysis

“…The mechanisms of lung damage from organic dust may work partly through one of its constituents, endotoxin. Endotoxin is a building stone of the outer membrane of Gram-negative bacteria and is considered to be a possible cause of respiratory disease among workers exposed to organic dust due to its strong potency in comparison with other proinflammatory microbial constituents of organic dust 9. The association between exposure to endotoxin and acute decline in lung function was first described by Castellan et al 10.…”

Evaluation of exposure–response relationships for health effects of microbial bioaerosols – A systematic review

“…Another comprehensive review systematically analyzed levels of personal exposure to endotoxin irrespective of health effects. The authors also stress the need to establish health-based exposure limits (Basinas et al, 2015). Already in 1998, the Dutch Expert Committee on Occupational Standards (DECOS) published an occupational health-based exposure limit concentration of 50 EU/m 3 for endotoxin (DECOS, 1998).…”

Endotoxin exposure and puberty in female rats: the role of nitric oxide and caspase-1 inhibition in neonates

“…They are detected in homes (e.g., dust, humidifiers, drinking water), agricultural environments (e.g., farms, dairy barns, poultry, swine confinement, rice, animal feed, grain dust), wastes (collected, composted, fuel plants, sewage), and industrial settings (wood handling, saw mills, de-barking, metal cutting fluid, potato processing, cigarette manufacturing, cotton mills, breweries, biotechnology) in levels from nanograms to micrograms per cubic metre (Rylander 2002;Duquenne et al 2014). Endotoxin-contaminated organic dusts are considered the most significant respiratory hazard within these environments (Rylander 2002;Basinas et al 2015). Bacterial infections and digestive system microbiota constitute major endogenous sources of endotoxins (Glaros et al 2013).…”