Impacts of Intensive Livestock Production on Human Health in Densely Populated Regions

Zoonotic bacteria in the vicinity of animal farms as a factor disturbing the human microbiome: a review

This review is aimed at summarizing the current state of knowledge about the relationship between environmental exposure to the bioaerosol emitted by intensive livestock farming and changes in the microbiome of people living in livestock farm vicinity. The PubMed, Scopus and Web of Science databases were searched by crossing keywords from the following 3 groups: a) "livestock," "animal farms," "animal breeding"; b) "microbiome," "resistome"; c) "livestock vicinity," "farm vicinity," "neighborhoods and health" in 2010-2022. Literature screening did not reveal any paper related to the full microbiome composition in the population studied. In the study, the authors included 7 papers (5 from the Netherlands, 1 from the USA, and 1 from China). The studies confirmed the carriage of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), livestockassociated MRSA (LA-MRSA MC398) and multidrug-resistant S. aureus (MDRSA) in the nasal microbiome of adults and children living within 500-2000 m from a livestock farm. Clostridium difficile, including LA-ribotype RT078 carriage, was detected in the intestinal microbiome of adults living within 500-1000 m. Extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae were confirmed in the intestinal microbiome of adults living within 500-6200 m. Knowledge on the composition of the microflora of people living in livestock farm vicinity is insufficient to conclude about changes in the microbiome caused by the environmental emission of bioaerosol. The carriage prevalence of the LA-bacteria, including both strains with antimicrobial resistance and antimicrobial resistance genes, confirms the presence of zoonotic bacteria in the human microflora in populations without occupational contact with animals. It cannot be ruled out that zoonotic bacteria, as a component of the microbiome, have a negative impact on people's health. Int J Occup Med Environ Health. 2024;37(2):138-52.

Short-term residential exposure to endotoxin emitted from livestock farms in relation to lung function in non-farming residents

BACKGROUND

Evidence on the public health relevance of exposure to livestock farm emissions is increasing. Research mostly focused on chemical air pollution, less on microbial exposure, while endotoxins are suggested relevant bacterial components in farm emissions. Acute respiratory health effects of short-term exposure to livestock-related air pollution has been shown for NH3 and PM10, but has not yet been studied for endotoxin. We aimed to assess associations between lung function and short-term exposure to livestock farming emitted endotoxin in co-pollutant models with NH3 and PM10.

METHODS

In 2014/2015, spirometry was conducted in 2308 non-farming residents living in a rural area in the Netherlands. Residential exposure to livestock farming emitted endotoxin during the week prior to spirometry was estimated by dispersion modelling. The model was applied to geo-located individual barns within 10 km of each home address using provincial farm data and local hourly meteorological conditions. Regional week-average measured concentrations of NH3 and PM10 were obtained through monitoring stations. Lung function parameters (FEV1, FVC, FEV1/FVC, MMEF) were expressed in %-predicted value based on GLI-2012. Exposure-response analyses were performed by linear regression modelling.

RESULTS

Week-average endotoxin exposure was negatively associated with FVC, independently from regional NH3 and PM10 exposure. A 1.1% decline in FVC was estimated for an increase of endotoxin exposure from 10th to 90th percentile. Stratified analyses showed a larger decline (3.2%) for participants with current asthma and/or COPD. FEV1 was negatively associated with week-average endotoxin exposure, but less consistent after co-pollutant adjustment. FEV1/FVC and MMEF were not associated with week-average endotoxin exposure.

CONCLUSIONS

Lower lung function in non-farming residents was observed in relation to short-term residential exposure to livestock farming emitted endotoxin. This study indicates the probable relevance of exposure to microbial emissions from livestock farms considering public health besides chemical air pollution, necessitating future research incorporating both.

Hazards Associated with the Combined Application of Fungicides and Poultry Litter in Agricultural Areas

In recent decades, the poultry farming industry has assumed a pivotal role in meeting the global demand for affordable animal proteins. While poultry farming makes a substantial contribution to food security and nutrition, it also presents environmental and public health challenges. The use of poultry litter as fertilizer for agricultural soils raises concerns about the transfer of pathogens and drug-resistant microorganisms from poultry farms to crop production areas. On the other hand, according to the Food and Agriculture Organization of the United Nations (FAO), fungicides represent the second most used chemical group in agricultural practices. In this context, agricultural soils receive the application of both poultry litter as a fertilizer and fungicides used in agricultural production. This practice can result in fungal contamination of the soil and the development of antifungal resistance. This article explores the necessity of monitoring antifungal resistance, particularly in food production areas with co-application of poultry litter and fungicides. It also highlights the role of fungi in ecosystems, decomposition, and mutualistic plant associations. We call for interdisciplinary research to comprehensively understand fungal resistance to fungicides in the environment. This approach seeks to promote sustainability in the realms of human health, agriculture, and the environment, aligning seamlessly with the One Health concept.

Increased risk of pneumonia amongst residents living near goat farms in different livestock-dense regions in the Netherlands

BACKGROUND

Previous studies, performed between 2009-2019, in the Netherlands observed an until now still unexplained increased risk for pneumonia among residents living close to goat farms. Since data were collected in the provinces Noord-Brabant and Limburg (NB-L), an area with relatively high air pollution levels and proximity to large industrial areas in Europe, the question remains whether the results are generalizable to other regions. In this study, a different region, covering the provinces Utrecht, Gelderland, and Overijssel (UGO) with a similar density of goat farms, was included to assess whether the association between goat farm proximity and pneumonia is consistently observed across the Netherlands.

METHODS

Data for this study were derived from the Electronic Health Records (EHR) of 21 rural general practices (GPs) in UGO, for 2014-2017. Multi-level analyses were used to compare annual pneumonia prevalence between UGO and data derived from rural reference practices ('control area'). Random-effects meta-analysis (per GP practice) and kernel analyses were performed to study associations of pneumonia with the distance between goat farms and patients' home addresses.

RESULTS

GP diagnoses of pneumonia occurred 40% more often in UGO compared to the control area. Meta-analysis showed an association at a distance of less than 500m (~70% more pneumonia compared to >500m) and 1000m (~20% more pneumonia compared to >1000m). The kernel-analysis for three of the four individual years showed an increased risk up to a distance of one or two kilometers (2-36% more pneumonia; 10-50 avoidable cases per 100,000 inhabitants per year).

CONCLUSIONS

The positive association between living in the proximity of goat farms and pneumonia in UGO is similar to the previously found association in NB-L. Therefore, we concluded that the observed associations are relevant for regions with goat farms in the entire country.

One Health Approach to Tackle Microbial Contamination on Poultries-A Systematic Review

This study reports the search of available data published regarding microbial occupational exposure assessment in poultries, following the PRISMA methodology. Air collection through filtration was the most frequently used. The most commonly used passive sampling method was material collection such as dust, cages, soils, sediment, and wastewater. Regarding assays applied, the majority of studies comprised culture-based methods, but molecular tools were also frequently used. Screening for antimicrobial susceptibility was performed only for bacteria; cytotoxicity, virological and serological assays were also performed. Most of the selected studies focused on bacteria, although fungi, endotoxins, and β-glucans were also assessed. The only study concerning fungi and mycotoxins reported the carcinogenic mycotoxin AFB1. This study gives a comprehensive overview of microbial contamination in the poultry industry, emphasizing this setting as a potential reservoir of microbial pathogens threatening human, animal, and environmental health. Additionally, this research helps to provide a sampling and analysis protocol proposal to evaluate the microbiological contamination in these facilities. Few articles were found reporting fungal contamination in poultry farms worldwide. In addition, information concerning fungal resistance profile and mycotoxin contamination remain scarce. Overall, a One Health approach should be incorporated in exposure assessments and the knowledge gaps identified in this paper should be addressed in further research.

Cell-based meat labeling – current worldwide legislation status

A growing interest has been noted if both industry operatives and consumers in cell-based meat (CBM), as visible in the increasing investment into this technology by major food industry corporations. However, in almost all countries worldwide, there is a lack of clear legislation with regard to the labeling of such products. The aim of the article is to collect and review current legal regulations concerning the international approval and labeling these types of products. In the manuscript, we reviews and analyze the legal situation of CBM and its labelling in countries from 4 different continents (EU members, the UK, the USA, Canada, Australia and New Zealand, Japan, Singapore and Israel). Aside from Singapore, no other country has approved CBM for placement on the market. The US has reached an agreement and established regulatory frameworks on CBM matters, where both the USDA and the FDA will be the control institutions. Within the European Union, CBM products will be evaluated under the Novel Food Regulation. The most anticipated process in other countries is the evaluation of CBM under the legislation on novel foods and subsequent amendments. Since local laws are still being developed, special care should be taken by the policymakers to avoid implementing local laws which could cause a negative approach to the technology by the consumers.

From natural environment to animal tissues: A review of microplastics(nanoplastics) translocation and hazards studies

Microplastics (MPs) and nanoplastic (NPs) pollution is a global concern due to the massive use of plastic products. Although there have been many studies on the treatments of animals with MPs/NPs, there are few systematic summaries of MPs/NPs translocation and hazards in animals. This review comprehensively summarizes the pathways by which animals are exposed to MPs/NPs in the environment, in particular, to summarize in detail their translocation and hazards in vivo. Studies have shown that MPs/NPs enter the animals' body through water, food, breath and even skin, enter the blood circulation through the lungs and digestive tract, and eventually accumulate in various tissues. After a summary of the studies, we found a high correlation between the tissue accumulation of MPs/NPs and their particle size, with 4-20 μm MPs appearing to be more prone to accumulate in tissues. These MPs/NPs accumulated in animal tissues may be transferred to humans through the food chain. Thus, we summarized the studies on the accumulation of MPs/NPs in livestock and poultry products, showing that MPs/NPs in livestock and poultry products gradually increased with the complexity of processing and packaging processes. There are few reports related to direct contamination of livestock products by MPs/NPs, we hope that this review will bring together the growing body of evidence that MPs/NPs can directly harm human health through the food chain.

Protect European green agricultural policies for future food security

European green agricultural policies have been relaxed to allow cultivation of fallow land to produce animal feed and meet shortfalls in exports from Ukraine and Russia. However, conversion of semi-natural habitats will disproportionately impact long term biodiversity and food security.

A Review of the Effectiveness of Current US Policies on Antimicrobial Use in Meat and Poultry Production

PURPOSE

Industrial food animal production accounts for most animal-source protein consumed in the USA. These operations rely on an array of external inputs, which can include antimicrobials of medical importance. The use of these drugs in this context has been the subject of public health debate for decades because their widespread use contributes to the selection for and proliferation of drug-resistant bacteria and their genetic determinants. Here, we describe legislative and regulatory efforts, at different levels of governance in the USA, to curtail food animal consumption of medically important antimicrobials.

RECENT FINDINGS

The features and relative success of the US efforts are examined alongside those of selected member states (Denmark and the Netherlands) of the European Union. Evaluation of efforts at all levels of US governance was complicated by shortcomings in prescribed data collection; nevertheless, available information suggests deficiencies in policy implementation and enforcement compromise the effectiveness of interventions pursued to date. The political will, robust systems for collecting and integrating data on antimicrobial consumption and use, and cross-sectoral collaboration that have been integral to the success of efforts in Denmark and The Netherlands have been notably absent in the USA, especially at the federal level.

Evolution and Neural Network Prediction of CO2 Emissions in Weaned Piglet Farms

This paper aims to study the evolution of CO₂ concentrations and emissions on a conventional farm with weaned piglets between 6.9 and 17.0 kg live weight based on setpoint temperature, outdoor temperature, and ventilation flow. The experimental trial was conducted during one transition cycle. Generally, the ventilation flow increased with the reduction in setpoint temperature throughout the cycle, which caused a reduction in CO₂ concentration and an increase in emissions. The mean CO₂ concentration was 3.12 g m^–3. Emissions of CO₂ had a mean value of 2.21 mg s⁻¹ per animal, which is equivalent to 0.195 mg s⁻¹ kg⁻¹. A potential function was used to describe the interaction between 10 min values of ventilation flow and CO₂ concentrations, whereas a linear function was used to describe the interaction between 10 min values of ventilation flow and CO₂ emissions, with r values of 0.82 and 0.85, respectively. Using such equations allowed for simple and direct quantification of emissions. Furthermore, two prediction models for CO₂ emissions were developed using two neural networks (for 10 min and 60 min predictions), which reached r values of 0.63 and 0.56. These results are limited mainly by the size of the training period, as well as by the differences between the behavior of the series in the training stage and the testing stage.

Potential Application of Urease and Nitrification Inhibitors to Mitigate Emissions from the Livestock Sector: A Review

Human activities have caused an increase in greenhouse gas emissions, resulting in climate change that affects many factors of human life including its effect on water and food quality in certain areas with implications for human health. CH₄ and N₂O are known as potent non-CO₂ GHGs. The livestock industry contributes to direct emissions of CH₄ (38.24%) and N₂O (6.70%) through enteric fermentation and manure treatment, as well as indirect N₂O emissions via NH₃ volatilization. NH₃ is also a secondary precursor of particulate matter. Several approaches have been proposed to address this issue, including dietary management, manure treatment, and the possibility of inhibitor usage. Inhibitors, including urease and nitrification inhibitors, are widely used in agricultural fields. The use of urease and nitrification inhibitors is known to be effective in reducing nitrogen loss from agricultural soil in the form of NH₃ and N₂O and can further reduce CH₄ as a side effect. However, the effectiveness of inhibitors in livestock manure systems has not yet been explored. This review discusses the potential of inhibitor usage, specifically of N-(n-butyl) thiophosphoric triamide, dicyandiamide, and 3,4-dimethylpyrazole phosphate, to reduce emissions from livestock manure. This review focuses on the application of inhibitors to manure, as well as the association of these inhibitors with health, toxicity, and economic benefits.

The air we breathe: understanding the impact of the environment on pneumonia

An increased risk of community-acquired pneumonia has been shown in residents of rural livestock farming areas in the Netherlands and United States, probably due to air pollution exposure or zoonotic infections. Spatial epidemiological analyses have particularly implicated poultry and goat farms in the increased risk-an observation that warrants further research. Studying the viral or bacterial etiology of community-acquired pneumonia using traditional microbiological methods or metagenomic sequencing could help to fathom to what extent environmental factors and causative pathogens contribute to spatial differences in the incidence of severe acute respiratory infections.

The Role of Selected Ecosystem Services in Different Farming Systems in Poland Regarding the Differentiation of Agricultural Land Structure

The functioning of various agroecosystems is nowadays shaped by different farming systems, which may impair their functions, as well as being beneficial to them. The benefits include ecosystem services, defined as economic and noneconomic values gained by humans from ecosystems, through supporting soil formation and nutrient circulation, and the impact of agriculture on climate and biodiversity. Their mutual flow and various disturbances depend on the agroecosystem’s management method, which is associated with the type of management of agricultural land (AL) in individual farms. This paper raises a problem of transformation in the structure of three main farming systems in Poland, in 2004–2018, in relation to the implementation of 16 selected ecosystem services and their scale. Special attention was given to organic farming, as the most environmentally friendly and sustainable. The analysis demonstrates the increase in ALs in that type of production during the analyzed period of time. Disparities of transformation associated with the type of agricultural system were noticeable at the regional level, which were presented in 16 Polish voivodeships. The results of the analysis confirm that the organic system, which is an important carrier of various ecosystem services, gained a stable position. Moreover, areas with integrated farming still do not exceed 0.5% of total agricultural lands in such voivodeships. The analysis of factors influencing the deterioration or disappearance of selected environmental services characterizing agricultural systems indicates the need to depart from an intensive conventional management system.

Linkages between environmental issues and zoonotic diseases: with reference to COVID-19 pandemic

Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) has taken mankind by surprise with various unprecedented impacts on human life around the globe. This zoonotic pandemic is proving to be the most destructive disease outbreaks since decades. The increasing human population and anthropogenic activities have impacted the environment and have direct linkages with the current and other recent outbreaks of zoonotic diseases. Despite having a difference in their origin, major reasons behind the emergence and spread of zoonotic pandemics are related to activities such as habitat fragmentation, deforestation, biodiversity loss, intensive agriculture and livestock farming, uncontrolled urbanization, pollution, climate change and bushmeat hunting and trading. It is important to focus on environmental and climatic factors that are involved in the emergence of such pandemics involving novel human pathogens and viruses in particular. Research and data analysis, particularly in relation to COVID-19, has shown that meteorological factors along with population density and living conditions (particularly in the urban and semi-urban areas) play a crucial role in the intensity, evolution and spread of SARS-CoV-2. This particular virus is novel but coronaviruses have a long history and are known to cause disease outbreaks earlier as well. COVID-19 pandemic provides learning for the future, in particular the importance of environmental sustainability for controlling such outbreaks. A strategic plan can be developed involving policy-makers, organizations, and governments to control the onset and spread of the novel pathogens. This review-based study recommends that prevention of COVID-19 like pandemics from re-occurring is through tackling the issues related to the environment by controlling anthropogenic activities. It will also be important to track the lineage and future evolution course of such human pathogens so as to determine the nexus of environmental and biological factors in the development and spread of novel strains.

The Impact of Bushfire Smoke on Cattle-A Review

Simple Summary

In 2019–2020, Australia had a particularly bad bushfire season which resulted in large numbers of people and animals being exposed to smoke haze for several weeks. We conducted a literature review to examine the evidence for effects of prolonged exposure to bushfire smoke on cattle. There was general agreement that small airborne particulate matter in smoke is the substance most likely to cause problems. There was indirect evidence about effects on cattle caused by other types of pollution containing particulate matter. We found little evidence to support severe effects on cattle. This may be because cattle do not tend to suffer from the co-morbidities that, in the human population, seem to be made worse by smoke and pollution. However, small changes to death rates or disease that is not severe may go unreported, so further study is warranted.

Abstract

In 2019–2020, a particularly bad bushfire season in Australia resulted in cattle being exposed to prolonged periods of smoke haze and reduced air quality. Bushfire smoke contains many harmful pollutants, and impacts on regions far from the fire front, with smoke haze persisting for weeks. Particulate matter (PM) is one of the major components of bushfire smoke known to have a negative impact on human health. However, little has been reported about the potential effects that bushfire smoke has on cattle exposed to smoke haze for extended periods. We explored the current literature to investigate evidence for likely effects on cattle from prolonged exposure to smoke generated from bushfires in Australia. We conducted a search for papers related to the impacts of smoke on cattle. Initial searching returned no relevant articles through either CAB Direct or PubMed databases, whilst Google Scholar provided a small number of results. The search was then expanded to look at two sub-questions: the type of pollution that is found in bushfire smoke, and the reported effects of both humans and cattle being exposed to these types of pollutants. The primary mechanism for damage due to bushfire smoke is due to small airborne particulate matter (PM). Although evidence demonstrates that PM from bushfire smoke has a measurable impact on both human mortality and cardiorespiratory morbidities, there is little evidence regarding the impact of chronic bushfire smoke exposure in cattle. We hypothesize that cattle are not severely affected by chronic exposure to smoke haze, as evidenced by the lack of reports. This may be because cattle do not tend to suffer from the co-morbidities that, in the human population, seem to be made worse by smoke and pollution. Further, small changes to background mortality rates or transient morbidity may also go unreported.

Tracing the animal sources of surface water contamination with Campylobacter jejuni and Campylobacter coli

Campylobacter jejuni and C. coli, the primary agents of human bacterial gastroenteritis worldwide, are widespread in surface water. Several animal sources contribute to surface water contamination with Campylobacter, but their relative contributions thus far remained unclear. Here, the prevalence, genotype diversity, and potential animal sources of C. jejuni and C. coli strains in surface water in the Netherlands were investigated. It was also assessed whether the contribution of the different animal sources varied according to surface water type (i.e. agricultural water, surface water at discharge points of wastewater treatment plants [WWTPs], and official recreational water), season, and local livestock (poultry, pig, ruminant) density. For each surface water type, 30 locations spread over six areas with either high or low density of poultry, ruminants, or pigs, were sampled once every season in 2018-2019. Campylobacter prevalence was highest in agricultural waters (77%), and in autumn and winter (74%), and lowest in recreational waters (46%) and in summer (54%). In total, 76 C. jejuni and 177 C. coli water isolates were whole-genome sequenced. Most C. coli water isolates (78.5%) belonged to hitherto unidentified clones when using the seven-locus sequence type (ST) scheme, while only 11.8% of the C. jejuni isolates had unidentified STs. The origin of these isolates, as defined by core-genome multi-locus sequence typing (cgMLST), was inferred by comparison with Campylobacter strain collections from meat-producing poultry, laying hens, adult cattle, veal calves, small ruminants, pigs, and wild birds. Water isolates were mainly attributed to wild birds (C. jejuni: 60.0%; C. coli: 93.7%) and meat-producing poultry (C. jejuni: 18.9%; C. coli: 5.6%). Wild bird contribution was high among isolates from recreational waters and WWTP discharge points, and in areas with low poultry (C. coli) or high ruminant (C. jejuni) densities. The contribution of meat-producing poultry was high in areas with high density of poultry, springtime, agricultural waters and WWTP discharge points. While wild birds and poultry were the main contributors to Campylobacter contamination in surface water, their contribution differed significantly by water type, season, and local poultry and ruminant densities.

Review: Mitigating the risks posed by intensification in livestock production: the examples of antimicrobial resistance and zoonoses

Major shifts in how animals are bred, raised and slaughtered are involved in the intensification of livestock systems. Globally, these changes have produced major increases in access to protein-rich foods with high levels of micronutrients. Yet the intensification of livestock systems generates numerous externalities including environmental degradation, zoonotic disease transmission and the emergence of antimicrobial resistance (AMR) genes. Where the process of intensification is most advanced, the expertise, institutions and regulations required to manage these externalities have developed over time, often in response to hard lessons, crises and challenges to public health. By exploring the drivers of intensification, the foci of future intensification can be identified. Low- and middle-income (LMICs) countries are likely to experience significant intensification in livestock production in the near future; however, the lessons learned elsewhere are not being transferred rapidly enough to develop risk mitigation capacity in these settings. At present, fragmentary approaches to address these problems present an incomplete picture of livestock populations, antimicrobial use, and disease risks in LMIC settings. A worldwide improvement in evidence-based zoonotic disease and AMR management within intensifying livestock production systems demands better information on the burden of livestock-associated disease, antimicrobial use and resistance and resources allocated to mitigation.

Spatial Effects of Livestock Farming on Human Infections With Shiga Toxin-Producing Escherichia coli O157 in Small but Densely Populated Regions: The Case of the Netherlands

The role of environmental transmission of typically foodborne pathogens like Shiga toxin-producing Escherichia coli (STEC) O157 is increasingly recognized. To gain more insights into spatially restricted risk factors that play a role in this transmission, we assessed the spatial association between sporadic STEC O157 human infections and the exposure to livestock (i.e. small ruminants, cattle, poultry, and pigs) in a densely populated country: the Netherlands. This was done for the years 2007-2016, using a state-of-the-art spatial analysis method in which hexagonal areas with different sizes (90, 50, 25 and 10 km2) were used in combination with a novel probability of exposure metric: the population-weighted number of animals per hexagon. To identify risk factors for STEC O157 infections and their population attributable fraction (PAF), a spatial regression model was fitted using integrated nested Laplace approximation (INLA). Living in hexagonal areas of 25, 50 and 90 km2 with twice as much population-weighted small ruminants was associated with an increase of the incidence rate of human STEC O157 infections in summer (RR of 1.09 [95%CI;1.01-1.17], RR of 1.17 [95%CI;1.07-1.28] and RR of 1.13 [95%CI;1.01-1.26]), with a PAF of 49% (95%CI;8-72%). Results suggest exposure to small ruminants to be a risk factor, although no evidence on the mode of transmission is provided. Therefore, the underlying mechanisms warrant further investigation and could offer new targets for control. The newly proposed exposure metric has potential to improve existing spatial modeling studies on infectious diseases related to livestock exposure, especially in densely populated countries like the Netherlands.

Residential proximity to agriculture and risk of childhood leukemia and central nervous system tumors in the Danish national birth cohort

BACKGROUND

Living in an agricultural area or on farms has been associated with increased risk of childhood cancer but few studies have evaluated specific agricultural exposures. We prospectively examined residential proximity to crops and animals during pregnancy and risk of childhood leukemia and central nervous system (CNS) tumors in Denmark.

METHODS

The Danish National Birth Cohort (DNBC) consists of 91,769 pregnant women (96,841 live-born children) enrolled in 1996-2003. For 61 childhood leukemias and 59 CNS tumors <15 years of age that were diagnosed through 2014 and a ~10% random sample of the live births (N = 9394) with geocoded addresses, we linked pregnancy addresses to crop fields and animal farm locations and estimated the crop area (hectares [ha]) and number of animals (standardized by their nitrogen emissions) by type within 250 meters (m), 500 m, 1000 m, and 2000 m of the home. We also estimated pesticide applications (grams, active ingredient) based on annual sales data for nine herbicides and one fungicide that were estimated to have been applied to >30% of the area of one or more crop. We used Cox proportional hazard models (weighted to the full cohort) to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of childhood leukemia and CNS tumors with crop area, animals, and pesticide applications adjusted for gender and maternal age.

RESULTS

Sixty-three percent of mothers had crops within 500 m of their homes during pregnancy; winter and spring cereals were the major crop types. Compared to mothers with no crops <500 m, we found increasing risk of childhood leukemia among offspring of mothers with increasing crop area near their home (highest tertile >24 ha HR: 2.0, CI:1.02-3.8), which was stronger after adjustment for animals (within 1000 m) (HR: 2.6, CI:1.02-6.8). We also observed increased risk for grass/clover (highest tertile >1.1 ha HR: 3.1, CI:1.2-7.7), peas (>0 HR: 2.4, CI: 1.02-5.4), and maize (>0 HR: 2.8, CI: 1.1-6.9) in animal-adjusted models. We found no association between number of animals near homes and leukemia risk. Crops, total number of animals, and hogs within 500 m of the home were not associated with CNS tumors but we observed an increased risk with >median cattle compared with no animals in crop-adjusted models (HR = 2.2, CI: 1.02-4.9). In models adjusted for total animals, the highest tertiles of use of three herbicides and one fungicide were associated with elevated risk of leukemia but no associations were statistically significant; there were no associations with CNS tumors.

CONCLUSIONS

Risk of childhood leukemia was associated with higher crop area near mothers' homes during pregnancy; CNS tumors were associated with higher cattle density. Quantitative estimates of crop pesticides and other agricultural exposures are needed to clarify possible reasons for these increased risks.

Effects of Dutch livestock production on human health and the environment

Observed multiple adverse effects of livestock production have led to increasing calls for more sustainable livestock production. Quantitative analysis of adverse effects, which can guide public debate and policy development in this area, is limited and generally scattered across environmental, human health, and other science domains. The aim of this study was to bring together and, where possible, quantify and aggregate the effects of national-scale livestock production on 17 impact categories, ranging from impacts of particulate matter, emerging infectious diseases and odor annoyance to airborne nitrogen deposition on terrestrial nature areas and greenhouse gas emissions. Effects were estimated and scaled to total Dutch livestock production, with system boundaries including feed production, manure management and transport, but excluding slaughtering, retail and consumption. Effects were expressed using eight indicators that directly express Impact in the sense of the Drivers-Pressures-State-Impact-Response framework, while the remaining 14 express Pressures or States. Results show that livestock production may contribute both positively and negatively to human health with a human disease burden (expressed in disability-adjusted life years) of up to 4% for three different health effects: those related to particulate matter, zoonoses, and occupational accidents. The contribution to environmental impact ranges from 2% for consumptive water use in the Netherlands to 95% for phosphorus transfer to soils, and extends beyond Dutch borders. While some aggregation across impact categories was possible, notably for burden of disease estimates, further aggregation of disparate indicators would require normative value judgement. Despite difficulty of aggregation, the assessment shows that impacts receive a different contribution of different animal sectors. While some of our results are country-specific, the overall approach is generic and can be adapted and tuned according to specific contexts and information needs in other regions, to allow informed decision making across a broad range of impact categories.

Emerging zoonotic diseases originating in mammals: a systematic review of effects of anthropogenic land-use change

Zoonotic pathogens and parasites that are transmitted from vertebrates to humans are a major public health risk with high associated global economic costs. The spread of these pathogens and risk of transmission accelerate with recent anthropogenic land-use changes (LUC) such as deforestation, urbanisation, and agricultural intensification, factors that are expected to increase in the future due to human population expansion and increasing demand for resources.We systematically review the literature on anthropogenic LUC and zoonotic diseases, highlighting the most prominent mammalian reservoirs and pathogens, and identifying avenues for future research.The majority of studies were global reviews that did not focus on specific taxa. South America and Asia were the most-studied regions, while the most-studied LUC was urbanisation. Livestock were studied more within the context of agricultural intensification, carnivores with urbanisation and helminths, bats with deforestation and viruses, and primates with habitat fragmentation and protozoa.Research into specific animal reservoirs has improved our understanding of how the spread of zoonotic diseases is affected by LUC. The behaviour of hosts can be altered when their habitats are changed, impacting the pathogens they carry and the probability of disease spreading to humans. Understanding this has enabled the identification of factors that alter the risk of emergence (such as virulence, pathogen diversity, and ease of transmission). Yet, many pathogens and impacts of LUC other than urbanisation have been understudied.Predicting how zoonotic diseases emerge and spread in response to anthropogenic LUC requires more empirical and data synthesis studies that link host ecology and responses with pathogen ecology and disease spread. The link between anthropogenic impacts on the natural environment and the recent COVID-19 pandemic highlights the urgent need to understand how anthropogenic LUC affects the risk of spillover to humans and spread of zoonotic diseases originating in mammals.

A Survey of Dairy Cattle Behavior in Different Barns in Northern Italy

Simple Summary

The climate crisis is accompanied by an increasing number of heat waves that negatively affect the behavior of dairy cows and their welfare. To understand if and how this is affecting farms in Northern Italy, a survey was carried out on eight cattle farms located in the Lombardy region. Three periods were monitored for one year (thermoneutral, hot and cold seasons) using environmental sensors installed in the barn and accelerometers mounted on the hind leg of groups of cows. From the results, it emerged that cows react to high air temperature and humidity conditions by reducing their lying time, which negatively affects milk production. Four out of the eight investigated farms showed that the negative effects caused by heat stress were evident. Hence, the farmer should consider the possibility of improving the barn structure, for example with an efficacious forced ventilation system. Cattle welfare is the first step towards healthy and productive cows.

Abstract

Due to its increasing pressure on dairy cows, studies that investigate how to cope with heat stress are needed. The heat stress affects multiple aspects of cows’ lives, among which their behavior and welfare. In this study, a survey was carried out in eight farms located in Northern Italy to monitor and evaluate the environmental aspects of the barns and the behavioral responses of dairy cows. For one year, three periods were monitored: thermoneutral (T_S), hot (H_S) and cold (C_S) seasons. Temperature and relative humidity were measured by environmental sensors, and lying vs. standing time, number of lying bouts and their average duration were collected by accelerometers. The temperature-humidity index (THI) was quantified inside and outside of the barn. Results show that at the increase of the THI, behavioral adaptations occurred in all the farms, especially with a reduction of lying time and an increase of respiration rate. Four of the eight farms need interventions for improving the cows’ welfare. Here, environmental problems should be solved by introducing or improving the efficacy of the forced ventilation or by modifying the barn structure. Monitoring dairy barns with sensors and Precision Livestock Farming techniques can be helpful for future livestock farming to alert farmers on the need for their interventions to respond immediately to unwanted barn living conditions.

Pig barns ammonia and greenhouse gas emission mitigation by slurry aeration and acid scrubber

Livestock production is associated with several gaseous pollutant emissions to the environment. These emissions can degrade local and regional air quality, contribute to surface water eutrophication and acid rain, and contribute to the greenhouse gas footprint of the production sector. Modern production systems must balance animal welfare and environmental pollution potential with economic reality, which is a great challenge to maintain as global demand for animal protein increases. Accordingly, gaseous emission technologies were the main target for this research, in which mitigating gas emissions of ammonia, nitrous oxide, and methane from pig production facilities via slurry aeration system was tested. Five treatments with different airflow rates in the test room were examined continuously over a period of 6 weeks and the results were compared with the control room. Test results indicate that the highest mitigation potentials were 12, 57.6, and 10.4% for nitrous oxide, methane, and ammonia, respectively. Subsequently directing exhaust air into a sulfuric acid air scrubber at 3.0 pH further reduced total ammonia emissions by 80 to 87%.

Morbidity Rates in an Area with High Livestock Density: A Registry-Based Study Including Different Groups of Patients with Respiratory Health Problems

There is continuing debate and public health concern regarding the previously confirmed association between high livestock density and human health. The primary aim of the current study is to assess the prevalence of respiratory and other health problems in a livestock dense area in the Netherlands, based on recent longitudinal health data and a large sample. Analyses are expanded with the investigation of different subgroups of patients with respiratory health problems and the inclusion of various chronic and acute health outcomes, as well as prescribed medication. Prevalence of health symptoms and chronic conditions was assessed for the period 2014-2016, based on electronic health records registered in 26 general practices located in areas with intensive livestock farming in the Netherlands ("livestock dense area", n = 117,459 unique residents in total). These were compared with corresponding health data from general practices (n = 22) in different rural regions with a low density of livestock farms or other major environmental exposures ("control area", n = 85,796 unique residents in total). Multilevel regression models showed a significantly higher prevalence of pneumonia in the total sample in the livestock dense area, which was also observed among susceptible subgroups of children, the elderly, and patients with chronic obstructive pulmonary disease (COPD). Lower respiratory tract infections, respiratory symptoms, vertigo, and depression were also more common in the livestock dense area compared to the control area. In general, there were no significant differences in chronic conditions such as asthma, COPD, or lung cancer. Prescription rates for broad-spectrum antibiotics were more common among patients with pneumonia in the livestock dense area. Acute respiratory infections and symptoms, but not chronic conditions, were considerably more common in areas with a high livestock density. Identification of causal pathogens on the basis of serological analyses could further elucidate the underlying mechanisms behind the observed health effects.

A Review of Potential Public Health Impacts Associated With the Global Dairy Sector

Strong demand for dairy products has led to a global increase in dairy production. In many parts of the world, dairy systems are undergoing rapid intensification. While increased production may contribute to food security, higher dairy stocking rates in some regions have resulted in increased pressure on natural resources with the potential to affect public health and wellbeing. The aim of this review was to identify and describe the potential health harms and benefits associated with dairy production and consumption. Electronic databases Medline, Embase, Scopus, Web of Science, PubMed, and Google Scholar were searched for published literature that investigated human health impacts of dairy production and consumption. Occupational hazards, environmental health impacts, ecosystem health impacts, foodborne hazards, and diet-related chronic diseases were identified as potential public health hazards. Some impacts, notably climate change, extend beyond directly exposed populations. Dairy production and consumption are also associated with important health benefits through the provision of nutrients and economic opportunities. As the global dairy sector increases production, exposure to a range of hazards must be weighed with these benefits. The review of impacts presented here can provide an input into decision making about optimal levels of dairy production and consumption, local land use, and identification and management of specific hazards from this sector. Future research should consider multiple exposure routes, socioeconomic implications, and environmental factors, particularly in regions heavily dependent on dairy farming.

Risk of pneumonia among residents living near goat and poultry farms during 2014-2016

In the Netherlands, an association was found between the prevalence of pneumonia and living near goat and poultry farms in 2007-2013. This association then led to regulatory decisions to restrict the building of new goat farms and to reduce emissions of poultry farms. Confirmation of these results, however, is required because the period of previous analyses overlapped a Q-fever epidemic in 2007-2010. To confirm the association, we performed a population-based study during 2014-2016 based on general practitioner (GP) data. Electronic medical records of 90,183 persons were used to analyze the association between pneumonia and the population living in the proximity (within 500-2000 m distance) of goat and poultry farms. Data were analyzed with three types of logistic regression (with and without GP practice as a random intercept and with stratified analyses per GP practice) and a kernel model to discern the influence of different statistical methods on the outcomes. In all regression analyses involving adults, a statistically significant association between pneumonia and residence within 500 meters of goat farms was found (odds ratio [OR] range over all analyses types: 1.33-1.60), with a decreasing OR for increasing distances. In kernel analyses (including all ages), a population-attributable risk between 6.0 and 7.8% was found for a distance of 2000 meters in 2014-2016. The associations were consistent across all years and robust for mutual adjustment for proximity to other animals and for several other sensitivity analyses. However, associations with proximity to poultry farms are not supported by the present study. As the causes of the elevated pneumonia incidence in persons living close to goat farms remain unknown, further research into potential mechanisms is required for adequate prevention.

Intensive Livestock Farming and Residential Health: Experts' Views

The presence of intensive livestock farms in close vicinity to residential areas in the Netherlands is a complex problem characterised by knowledge uncertainty about the effects on residential health, overlapping value-driven concerns and stakeholder diversity. In order to address concerns about the health effects and effectively manage the debate about intensive livestock farming, constructive stakeholder dialogues are encouraged, informed by current scientific insights. We explored the current knowledge, beliefs and concerns of scientific experts, following the mental models approach. A summary expert model was derived from scanning the relevant literature and informed by interviews with 20 scientific experts. The study shows imprecise use of terminology by experts. Moreover, they appear to perceive intensive livestock farming not as a major health problem at least at this moment for neighbouring residents in the Netherlands. Broader themes such as (environmental) unsustainability and biodiversity loss seem a more prominent concern among the experts. Our study questions whether dialogues should only focus on residential health or cover broader values and concerns. However, mental models about risk may differ with other stakeholders, impeding communication. Hence, we will identify other stakeholders' knowledge, beliefs and value-based concerns in the light of facilitating constructed dialogues between stakeholders.

Concentrations and emissions of particulate matter and ammonia from extensive livestock farm in South China

Atmospheric particulate matter (PM) and ammonia pollution from livestock feeding have gradually become the environmental concerns due to the spring up of livestock farms in worldwide. However, researches about the formation of atmospheric particulate matter related to ammonia are still limited. Therefore, a study to survey the total suspended particles (TSP), PM with the diameter less than 10 μm (PM₁₀), PM₄, PM_2.5, PM₁, and ammonia was conducted at four types of hog houses distinguished by its building design as well as manure handling methods in South China. Four hog houses were monitored during three fattening periods from 2016 to 2017. The emissions of NH₃ per hog house averaged 210.42 μg s^-1. The emissions of PM per hog house averaged 2.017 μg h^-1 for PM₁, 2.149 μg h^-1 for PM_2.5, 2.305 μg h^-1 for PM₄, 3.950 μg h^-1 for PM₁₀, and 9.317 μg h^-1 for TSP. The emissions of PM per hog house average 2.017 μg h^-1, 2.149 μg h^-1, 2.305 μg h^-1, 3.950 μg h^-1, and 9.317 μg h^-1, respectively for PM₁, PM_2.5, PM₄, PM₁₀, and PM₁₀. In each hog house, while the quantity of manure determined the concentration of NH₃, biological fermentation bed was able to control the ammonia volatilization compared with other three manure handling methods. The largest percentage of fine PM (< 10 μm) is produced by the manual waterless method for manure handling. When it came to the manual waterless method, largest amount of fine PM (< 10 μm) was founded to form. Among various contributions of secondary inorganic PM to PM₁, the NH₃ was a dominant factor. Based on our experiment, the absolute concentration of NH₃ was inversely proportional to the concentration of PM₁ when the background influence was removed.

Residential proximity to livestock farms is associated with a lower prevalence of atopy

Objectives

Exposure to farm environments during childhood and adult life seems to reduce the risk of atopic sensitisation. Most studies have been conducted among farmers, but people living in rural areas may have similar protective effects for atopy. This study aims to investigate the association between residential proximity to livestock farms and atopy among non-farming adults living in a rural area in the Netherlands.

Methods

We conducted a cross-sectional study among 2443 adults (20–72 years). Atopy was defined as specific IgE to common allergens and/or total IgE ≥100 IU/mL. Residential proximity to livestock farms was assessed as 1) distance to the nearest pig, poultry, cattle or any farm, 2) number of farms within 500 m and 1000 m, and 3) modelled annual average fine dust emissions from farms within 500 m and 1000 m. Data were analysed with multiple logistic regression and generalised additive models.

Results

The prevalence of atopy was 29.8%. Subjects living at short distances from farms (<327 m, first tertile) had a lower odds for atopy compared with subjects living further away (>527 m, third tertile) (OR 0.79, 95% CI 0.63 to 0.98). Significant associations in the same direction were found with distance to the nearest pig or cattle farm. The associations between atopy and livestock farm exposure were somewhat stronger in subjects who grew up on a farm.

Conclusions

Living in close proximity to livestock farms seems to protect against atopy. This study provides evidence that protective effects of early-life and adult farm exposures may extend beyond farming populations.