Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper

Abstract

Farmers constitute a large professional group worldwide. In developed countries farms tend to become larger, with a concentration of farm operations. Animal farming has been associated with negative respiratory effects such as work‐related asthma and rhinitis. However, being born and raised or working on a farm reduces the risk of atopic asthma and rhinitis later in life. A risk of chronic bronchitis and bronchial obstruction/COPD has been reported in confinement buildings and livestock farmers. This position paper reviews the literature linking exposure information to intensive animal farming and the risk of work‐related respiratory diseases and focuses on prevention. Animal farming is associated with exposure to organic dust containing allergens and microbial matter including alive microorganisms and viruses, endotoxins and other factors like irritant gases such as ammonia and disinfectants. These exposures have been identified as specific agents/risk factors of asthma, rhinitis, chronic bronchitis, COPD and reduced FEV1. Published studies on dust and endotoxin exposure in livestock farmers do not show a downward trend in exposure over the last 30 years, suggesting that the workforce in these industries is still overexposed and at risk of developing respiratory disease. In cases of occupational asthma and rhinitis, avoidance of further exposure to causal agents is recommended, but it may not be obtainable in agriculture, mainly due to socio‐economic considerations. Hence, there is an urgent need for focus on farming exposure in order to protect farmers and others at work in these and related industries from developing respiratory diseases and allergy.

An Ecological Study to Investigate Links Between Atmospheric Pollutants From Farming and SARS-CoV-2 Mortality

“…The data provided by the above cited-studies [45][46][47][48] suggests that a link between excess COVID-19-related mortality and farming-related atmospheric pollutants is biologically plausible. The specific association we found between COVID-19-related mortality and NH3 might be explained by the hypothesis that atmospheric NH3 leads to the formation of alkaline aerosol which triggers a conformation change in the SARS-CoV-2 spike that facilitates fusion of the viral envelope with the plasma membrane of target cells [49].…”

“…A study performed in an agricultural region of Washington State (US) found that industrial-scale animal feeding operations were associated with higher daily outdoor NH3 levels, and that forced expiratory volume in 1 second was lower with each interquartile increase in the previous day's NH3 exposure; however no associations with asthma symptoms were observed [47]. The European Academy of Allergy and Clinical Immunology position paper [48] has highlighted that increased risks of developing the respiratory diseases and allergies are associated with animal farming, and emphasized the need to protect workers from such risks.…”

Allergy protection at farms—just a myth?

“…Allergy on farms has a long history. “Hayfever,” one of the main allergic outcomes, has an origin in the farming community while also asthma is increased in farmers due to exposure to grain dust, animal dander and various chemicals, 1,2 Nevertheless Blackley 3 noted already in 1873 that “ these statistics of the occupations of hay‐fever patients bring out prominently the very curious circumstance that the persons who are most subjected to the action of pollen belong to a class which furnished the fewest cases of the disorder, namely, the farming class ”. This paradox has been rediscovered in 1989 by Gassner in the Canton of St. Gallen in the Swiss Alps, 4 followed by studies of Braun‐Fahrländer 5 among others.…”

Sex-Specific Differences in Resolution of Airway Inflammation in Fat-1 Transgenic Mice Following Repetitive Agricultural Dust Exposure

“…Agricultural workers are at increased risk for developing various respiratory diseases including chronic bronchitis, asthma, and COPD, due in part to exposure to respirable organic dusts associated with these environments ( Von Essen and Romberger, 2003 ; Nordgren and Charavaryamath, 2018 ; Sigsgaard et al, 2020 ). Individuals that work in concentrated animal feeding operations, such as those housing swine, have appreciably increased risk for negative lung health outcomes ( Iversen and Dahl, 2000 ; Kirkhorn and Garry, 2000 ; Pedersen et al, 2000 ; May et al, 2012 ; Pavilonis et al, 2013 ; Guillien et al, 2016 ; Nordgren and Bailey, 2016 ; Nordgren and Charavaryamath, 2018 ).…”