Effects of wildfire smoke exposure on innate immunity, metabolism, and milk production in lactating dairy cows

Mapping Research Priorities for Climate Change Adaptation in Agriculture: A One Health Perspective

BACKGROUND

The climate emergency poses significant threats to agricultural productivity, the health and economic prospects of agricultural workers, and animal welfare. This requires development and implementation of adaptation strategies to mitigate the impact in the long-term. The purpose of this study was to identify and map research priorities for climate change adaptation in agriculture, focusing on protecting the health of agricultural workers and livestock animals.

METHODS

Based on the One Health framework, we utilized a participatory, mixed-method approach called group concept mapping. In 2023, 20 faculty members from various disciplines at a land-grant university were recruited through email and purposive sampling, based on group concept mapping methodology. Fifteen faculty members brainstormed ways to reduce health risks for agricultural workers and livestock in the Pacific Northwest amid climate change. Forty ideas were sorted and rated for importance and feasibility by 11 and 10 faculty, respectively.

FINDINGS

Multidimensional scaling yielded five clusters: wildfire smoke impacts, basic science, forecasting extreme weather, tradeoffs, and occupational health and labor. Key research areas include studying wildfire smoke's effects on agricultural products, animals, and workers, and identifying adaptive strategies for climate change's impact on humans and livestock. Overall, 25% included all three pillars of the One Health framework.

CONCLUSIONS

Most research directions were focused on risk management, with limited emphasis on the One Health framework.

APPLICATION TO PRACTICE

Transdisciplinary collaboration is needed to apply a One Health approach in climate adaptation efforts for agriculture and can be enhanced through transdisciplinary education and training opportunities.

Wildfire Smoke: Health Effects, Mechanisms, and Mitigation

Wildfires are becoming more frequent and intense on a global scale, raising concerns about their acute and long-term effects on human health. We conducted a systematic review of the current epidemiological evidence on wildfire health risks and a meta-analysis to investigate the association between wildfire smoke exposure and various health outcomes. We discovered that wildfire smoke increases the risk of premature deaths and respiratory morbidity in the general population. Meta-analysis of cause-specific mortality and morbidity revealed that wildfire smoke had the strongest associations with cardiovascular mortality (RR: 1.018, 95% CI: 1.014-1.021), asthma hospitalization (RR: 1.054, 95% CI: 1.026-1.082), and asthma emergency department visits (RR: 1.117, 95% CI: 1.035-1.204) in the general population. Subgroup analyses of age found that adults and elderly adults were more susceptible to the cardiopulmonary effects of wildfire smoke. Next, we systematically addressed the toxicological mechanisms of wildfire smoke, including direct toxicity, oxidative stress, inflammatory reactions, immune dysregulation, genotoxicity and mutations, skin allergies, inflammation, and others. We discuss wildfire smoke risk mitigation strategies including public health interventions, regulatory measures, and personal actions. We conclude by highlighting current research limitations and future directions for wildfire research, such as elucidating the complex interactions of wildfire smoke components on human health, developing personalized risk assessment tools, and improving resilience and adaptation strategies to mitigate the health effects of wildfires in changing climate.

Seeing through the smoke: The effects of wildfire fine particulate matter (PM2.5) exposure on standing and lying behavior in Holstein heifer calves

Wildfires are burning more acres annually, contributing to air pollution across the United States. Air pollutants, such as particulate matter (PM2.5), have health implications for humans and animals, and are known to alter behavior in several species, but effects of wildfire PM2.5 on dairy calf behavior are unknown. The present study aimed to understand how dairy calf standing and lying behavior is affected by wildfire PM2.5. Holstein heifer calves (n = 13) were monitored for the first 90 d of life, concurrent with the 2022 wildfire season. Hourly PM2.5 concentrations and meteorological conditions, which were used to calculate temperature-humidity index (THI), were recorded. Wildfire and wind trajectory mapping was used to determine the contribution of wildfires to spikes in PM2.5. Calf activity data were recorded every minute using accelerometers and analyzed as total hourly and daily standing and lying times, standing and lying bouts, and duration of bouts. Additionally, the responses of calves to the initial 24-h period of each of 2 separate exposures to wildfire smoke were assessed. Wildfire PM2.5 exposure was associated with reduced daily standing time and bout duration, increased daily total lying time, and increased, albeit not significantly, daily standing bouts. Percent of time standing hourly was increased, whereas percent of time lying hourly was decreased by wildfire PM2.5. The initial 24 h of each smoke exposure was characterized by decreased standing and increased lying time, but there was a greater change in behavior during the first event compared with the second event. These results indicate that exposure to wildfire PM2.5 induces a behavioral response, which may diminish with repeated exposures. Future research should aim to understand the health and welfare implications of the behavioral responses to wildfire PM2.5.

Lnc-Clic5 as a sponge for miR-212-5p to inhibit cow barn PM2.5-induced apoptosis in rat alveolar macrophages

Particulate matter 2.5 (PM2.5) is a highly hazardous airborne particulate matter that poses a significant risk to humans and animals. Urban airborne particulate matter contributes to the increased incidence and mortality of respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), in humans. However, the specific mechanism by which PM2.5 affects animals in barn environments is yet to be elucidated. In this study, we investigated the effect of exposure to cow barn PM2.5 on rat alveolar macrophages (NR8383) and found that it induced apoptosis via the miR-212-5p/RASSF1 pathway. We found that lnc-Clic5 expression was downregulated in NR8383 cells exposed to cow barn PM2.5. Lnc-Clic5 plays a competitive endogenous RNA (ceRNA) regulatory role by sponging miR-212-5p to attenuate the regulation of RASSF1. Moreover, lnc-Clic5 overexpression inhibited NR8383 apoptosis by targeting the miR-212-5p/RASSF1 pathway. Co-treatment with miR-212-5p and lnc-Clic5 in the presence of cow barn PM2.5 revealed that lnc-Clic5 reversed NR8383 cell apoptosis induced by PM2.5 when miR-212-5p was overexpressed. These findings contribute to the study of ncRNAs and ceRNAs regulating PM2.5-induced apoptosis in animal farms, provide therapeutic targets for lung macrophage apoptosis, and may be useful for further evaluating the toxicological effects of PM2.5 in farmhouses on the respiratory systems of humans and animals.

Establishing the relationship between wildfire smoke and performance metrics on finished beef cattle in Western Rangelands

Identifying causal relationships is complicated. Researchers usually overlook causality behind relationships which can generate misleading associations. Herein, we carefully examine the parametric relationship and causality between wildfire smoke exposure and animal performance and behavior metrics over a period of 2 yr in Reno, Nevada. The animals in the 2020 smoke season were grain-finished (n = 12) and grass-finished (n = 12), whereas the animals during the 2021 season were fed under the same diet but finished with either a hormonal implant (n = 9), or without (n = 9). The dataset included daily records of feed intake (FI), body weight (BW), water intake (WI), average daily gain (ADG), and WI behavior (time spent drinking [TSD]; water intake events [WIE]; no-WIE [NWIE]). Variable tree length Bayesian additive regression trees (BART) were utilized to investigate the relationships between air quality index (AQI), particulate matter 2.5 μm (PM2.5) and 10 μm (PM10), NO2, SO2, Ozone, and CO levels in the air (sensors < 1.6 km from animals) with the animal data. Additionally, linear mixed models with a 7-d lag were used to evaluate parametric relationships among the same variables. All statistical analyses were performed on R Statistical Software (R Core Team 2023). Under the linear mixed model with a 7-d lag, significant positive and negative associations were found for all parameters examined (P < 0.05). Negative associations were found between FI, WI, ADG, BW, WIE, NWIE, TSD, and PM2.5 (P < 0.05) for at least one animal group. Positive linear associations between wildfire smoke parameters and the metrics evaluated were more variable and dependent on year, treatment, and smoke parameters. When examining the credible intervals and the variable importance in the BART, relationships were more difficult to identify. However, some associations were found for Ozone, AQI, NO2, CO, and PM10 (P < 0.05). Overall, our results carefully examine the relationship between smoke parameters and cattle performance and present interesting pathways previously unexplored that could guide early culling/finishing of animals to avoid economic losses associated with performance decrease in response to wildfire smoke exposure. Though interesting associations are found under linear mixed models, causality is difficult to establish, which highlights the need for controlled exposure experiments.

Pathways framework identifies wildfire impacts on agriculture

Wildfires are a growing concern to society and the environment in many parts of the world. Within the United States, the land area burned by wildfires has steadily increased over the past 40 years. Agricultural land management is widely understood as a force that alters fire regimes, but less is known about how wildfires, in turn, impact the agriculture sector. Based on an extensive literature review, we identify three pathways of impact-direct, downwind and downstream-through which wildfires influence agricultural resources (soil, water, air and photosynthetically active radiation), labour (agricultural workers) and products (crops and livestock). Through our pathways framework, we highlight the complexity of wildfire-agriculture interactions and the need for collaborative, systems-oriented research to better quantify the magnitude of wildfire impacts and inform the adaptation of agricultural systems to an increasingly fire-prone future.

Wildfire smoke linked to vocal changes in wild Bornean orangutans

Tropical peatlands are the sites of Earth's largest fire events, with outsized contributions to greenhouse gases, toxic smoke, and haze rich with particulate matter. The human health risks from wildfire smoke are well known, but its effects on wildlife inhabiting these ecosystems are poorly understood. In 2015, peatland fires on Borneo created a thick haze of smoke that blanketed the region. We studied its effects on the long call vocalizations of four adult male Bornean orangutans (Pongo pygmaeus wurmbii) in a peat swamp forest. During the period of heavy smoke, orangutans called less often and showed reduced vocal quality-lower pitch, increased harshness and perturbations, and more nonlinear phenomena-similar to changes in human smokers. Most of these changes persisted for two months after the smoke had cleared and likely signal changes in health. Our work contributes valuable information to support non-invasive acoustic monitoring of this Critically Endangered primate.

Effects of wildfire smoke PM2.5 on indicators of inflammation, health, and metabolism of preweaned Holstein heifers

Wildfires are a growing concern as large, catastrophic fires are becoming more commonplace. Wildfire smoke consists of fine particulate matter (PM2.5), which can cause immune responses and disease in humans. However, the present knowledge of the effects of wildfire PM2.5 on dairy cattle is sparse. The present study aimed to elucidate the effects of wildfire-PM2.5 exposure on dairy calf health and performance. Preweaned Holstein heifers (N = 15) were assessed from birth through weaning, coinciding with the 2021 wildfire season. Respiratory rate, heart rate, rectal temperatures, and health scores were recorded and blood samples were collected weekly or twice a week for analysis of hematology, blood metabolites, and acute phase proteins. Hourly PM2.5 concentrations and meteorological data were obtained, and temperature-humidity index (THI) was calculated. Contribution of wildfires to PM2.5 fluxes were determined utilizing AirNowTech Navigator and HYSPLIT modeling. Mixed models were used for data analysis, with separate models for lags of up to 7 d, and fixed effects of daily average PM2.5, THI, and PM2.5 × THI, and calf as a random effect. THI ranged from 48 to 73, while PM2.5 reached concentrations up to 118.8 µg/m3 during active wildfires. PM2.5 and THI positively interacted to elevate respiratory rate, heart rate, rectal temperature, and eosinophils on lag day 0 (day of exposure; all P < 0.05). There was a negative interactive effect of PM2.5 and THI on lymphocytes after a 2-d lag (P = 0.03), and total white blood cells, neutrophils, hemoglobin, and hematocrit after a 3-d lag (all P < 0.02), whereas there was a positive interactive effect on cough scores and eye scores on lag day 3 (all P < 0.02). Glucose and NEFA were increased as a result of combined elevated PM2.5 and THI on lag day 1, whereas BHB was decreased (all P < 0.05). Contrarily, on lag day 3 and 6, there was a negative interactive effect of PM2.5 and THI on glucose and NEFA, but a positive interactive effect on BHB (all P < 0.03). Serum amyloid A was decreased whereas haptoglobin was increased with elevated PM2.5 and THI together on lag days 0 to 4 (all P < 0.05). These findings indicate that exposure to wildfire-derived PM2.5, along with increased THI during the summer months, elicits negative effects on preweaned calf health and performance both during and following exposure.