Modeling Desert Dust Exposures in Epidemiologic Short-term Health Effects Studies.

BACKGROUND: Desert dust is assumed to have substantial adverse effects on human health. However, the epidemiologic evidence is still inconsistent, mainly because previous studies used different metrics for dust exposure and its corresponding epidemiologic analysis. We aim to provide a standardized approach to the methodology for evaluating the short-term health effects of desert dust. METHODS: We reviewed the methods commonly used for dust exposure assessment, from use of a binary metric for the occurrence of desert dust advections to a continuous one for quantifying particulate matter attributable to desert dust. We presented alternative time-series Poisson regression models to evaluate the dust exposure-mortality association, from the underlying epidemiological and policy-relevant questions. A set of practical examples, using a real dataset from Rome, Italy, illustrate the different modeling approaches. RESULTS: We estimate substantial effects of desert dust episodes and particulate matter with diameter <10 µm (PM10) on daily mortality. The estimated effect of non-desert PM10 was 1.8% (95% confidence interval [CI] = 0.4, 3.2) for a 10 µg/m rise of PM10 at lag 0 for dust days, 0.4% (95% CI = -0.1, 0.8) for non-dust days, and 0.6% (95% CI = -0.5, 2.1) for desert PM10. CONCLUSION: The standardized modeling approach we propose could be applicable elsewhere, in and near hot spots, which could lead to more consistent evidence on the health effects of desert dust from future studies.

Structuring a UK military role 1 medical treatment facility for a sustained mobile exercise in a hot desert environment: UK military exercise SAIF SAREEA 3.

Exercise SAIF SAREEA 3 (SS3) is a triservice combined joint training military Exercise between the UK and the Omani Armed forces. SS3 represented a rare opportunity to exercise a complete role 1 medical reception station (MRS) in a tented platform for a prolonged period providing 'real life support', as opposed to an exercise without casualties. This article is a discursive paper making recommendations for amendments to the established structure for the MRS within static high-temperature deployments. Considering the facility blueprint, recognising and implementing improvements to patient flow and increasing infection prevention control measures resulted in limiting the spread of disease outbreak. During the deployment there were considerable challenges delivering care in extreme heat above 50°C these included the use of environmental control units, white liners and refrigerator units which allowed care to be delivered throughout the day, and for the appropriate care of both casualties and medication. Finally, the article covers improved patient service with a paper-based triage system supporting innovative ideas to deliver care.

Heat acclimatisation on UK exercise SAIF SAREEA 3.

UK Exercise SAIF SAREEA 3 saw components of first Armoured Infantry Brigade conduct kinetic armoured infantry manoeuvres in Oman in temperatures that at times exceeded 50°C. This paper presents the methods of acclimatisation, recreational physical training in the heat, and reacclimatisation training conducted in theatre during this exercise. In order to reduce the risk of heat illness, individuals underwent either validated heat acclimatisation training in accordance with current policy, or adapted training as dictated by musculoskeletal restrictions or job specification. Direction was issued regarding recreational training. There was a theatre medical consensus agreed for the practice of returning soldiers to the exercise after admission to a medical treatment facility due to the effects of heat and data were collated on all LAND (Army) acclimatisation and heat illness presentations. The rates of climatic effect were much lower than expected in the medical estimate based on Exercise SAIF SAREEA 2 and similar exercises. Only five LAND patients fulfilled the in-theatre case definition of exertional heat illness of a deployed LAND forces population at risk of 2550. Zero patients who were returned to the exercise after symptoms associated with climatic exposure were subsequently readmitted with heat illness.

Short-term exposure to desert dust and the risk of acute myocardial infarction in Japan: a time-stratified case-crossover study.

Particulate matter from natural sources such as desert dust causes harmful effects for health. Asian dust (AD) increases the risk of acute myocardial infarction (AMI). However, little is known about the risk of myocardial infarction with nonobstructive coronary arteries (MINOCA), compared to myocardial infarction with coronary artery disease (MI-CAD). Using a time-stratified case-crossover design and conditional logistic regression models, the association between short-term exposure to AD whereby decreased visibility (< 10 km) observed at each monitoring station nearest to the hospitals was used for exposure measurements and admission for AMI in the spring was investigated using a nationwide administrative database between April 2012 and March 2016. According to presence of revascularization and coronary atherosclerosis, AMI patients (n = 30,435) were divided into 2 subtypes: MI-CAD (n = 27,202) or MINOCA (n = 3233). The single lag day-2 was used in AD exposure based on the lag effect analysis. The average level of meteorological variables and co-pollutants on the 3 days prior to the case/control days were used as covariates. The occurrence of AD events 2 days before the admission was associated with admission for MINOCA after adjustment for meteorological variables [odds ratio 1.65; 95% confidence interval (CI) 1.18-2.29], while the association was not observed in MI-CAD. The absolute risk difference of MINOCA admission was 1.79 (95% CI 1.21-2.38) per 100,000 person-year. These associations between AD exposure and the admission for MINOCA remained unchanged in two-pollutant models. This study provides evidence that short-term exposure to AD is associated with a higher risk of MINOCA, but not MI-CAD.

Chronic, sublethal effects of high temperatures will cause severe declines in southern African arid-zone birds during the 21st century.

Birds inhabiting hot, arid regions are among the terrestrial organisms most vulnerable to climate change. The potential for increasingly frequent and intense heat waves to cause lethal dehydration and hyperthermia is well documented, but the consequences of sublethal fitness costs associated with chronic exposure to sustained hot weather remain unclear. Using data for species occurring in southern Africa's Kalahari Desert, we mapped exposure to acute lethal risks and chronic sublethal fitness costs under past, present, and future climates. For inactive birds in shaded microsites, the risks of lethal dehydration and hyperthermia will remain low during the 21st century. In contrast, exposure to conditions associated with chronic, sublethal costs related to progressive body mass loss, reduced nestling growth rates, or increased breeding failure will expand dramatically. For example, by the 2080s the region will experience 10-20 consecutive days per year on which Southern Pied Babblers (Turdoides bicolor) will lose ∼4% of body mass per day, conditions under which this species' persistence will be extremely unlikely. Similarly, exposure to air temperature maxima associated with delayed fledging, reduced fledgling size, and breeding failure will increase several-fold in Southern Yellow-billed Hornbills (Tockus leucomelas) and Southern Fiscals (Lanius collaris). Our analysis reveals that sublethal costs of chronic heat exposure are likely to drive large declines in avian diversity in the southern African arid zone by the end of the century.

Monitoring daily events, coping strategies, and emotion during a desert expedition in the Middle East.

Personnel operating in extreme environmental conditions are exposed to a variety of stressors. Whether a person adjusts to the conditions and is able to cope has implications for their psychological health. In previous extreme-environment work, temporal changes in stress, coping, and emotion have been reported. Building on previous studies, we used a diary methodology to explore temporal changes in and associations between daily events, coping strategies, and affect during a unique hyperarid desert expedition. Four participants undertaking a crossing of the Empty Quarter desert were recruited to the study. Participants completed pre-expedition, postexpedition, and 4-month follow-up questionnaires. A daily self-report diary was used to collect situational data. Time-based changes were analysed before testing predictive models linking events and coping strategies with affective responses. Findings suggest that participants had an overall positive experience. There were changes in both the events experienced and coping strategies used during the expedition. Variation in events and coping strategies significantly predicted fluctuations in positive and negative affect. Results offer valuable mechanistic information that could inform monitoring systems aimed at tracking psychological variables during operations in extreme environments. Results are discussed in relation to the novel context, diary methodology, and implications for those operating in extremes.

[Should a doctor take into consideration the influence of climatic factors? Deliberations on the occasion of the publication of a new monograph (the book of essays of arid medicine by Z.R. Zununov, I.H. Nurov, and S.Z. Zununova)].

The authors analyze the monograph of the Uzbek scientists professor Z.R. Zununov, I.H. Nurov, and S.Z. Zununova «Essays of arid medicine¼ (Tashkent: «KAMALAK-PRESS¼ publishing house, 2016;540). The book presents the results of the comprehensive bioclimatic assessment of the arid zones of Uzbekistan, their extreme climatic conditions (such as high intensity and solar radiation and the considerable duration of its period, dry air and summer heat, sandstorms (the so-called «Afghans¼), and the great variety of the natural health-improving factors including mineral waters, microclimate of the speleotherapeutic cave, the desert dune sand, etc. The work is based on the authors' conceptual theory of «arid/meteorological stress syndrome¼, underlain by the hypothesis of the predominant role of hyperthermal weather hypoxia. A wide range of issues id discussed related to weather and climate adaptation of the healthy subjects (both indigenous and non-indigenous residents) and the patients suffering from ischemic heart disease, chronic obstructive pulmonary disease, and rheumatoid arthritis. Of special interest are the methods proposed for the correction of dysadaptive changes including the application of the natural balneotherapeutic factors existing in the arid zone (hydrogen sulphide and iodine-bromine balneotherapy, climatic therapy, speleotherapy, and psammotherapy (arenation). An important definitive conclusion at which the authors arrive is the necessity of the experimental observations in agreement with the requirements of the medico-biological ethics.

Effect of environmental factors on the germination and emergence of Salvia verbenaca L. cultivars (verbenaca and vernalis): An invasive species in semi-arid and arid rangeland regions.

Salvia verbenaca (wild sage) is a commonly cultivated herbal medicine plant, which is native to the Mediterranean climate regions of Europe, Africa, Asia and the Middle East. However, it has become an invasive species in semi-arid and arid regions of southern Australia. Two varieties are present in this region, var. verbenaca and var. vernalis, each of which can be distinguished by differences in morphology and flowering period. Following trials to determine the optimum temperate regime for germination and response to light and dark, seeds of both varieties were tested for their response to variations in pH, moisture stress, salinity, and burial depth. The temperature and light trial was carried out using three different temperature regimes; 30/20°C, 25/15°C and 20/12°C, and two light regimes; 12 hours light/12 hours dark and 24 hours dark, with var. vernalis responding to relatively higher temperatures than var. verbenaca. The germination rate of neither species was significantly inhibited by complete darkness when compared to rates under periodic light exposure. Both varieties germinated at near optimum rates strongly to very strongly in all pH buffer solutions, from pH 5 to pH 10, but they responded most strongly at neutral pH. Var. vernalis showed slightly more tolerance to reduced moisture availability, moderate to strong salinity, and burial depth, compared to var. verbenaca. However, even a fairly shallow burial depth of 2 cm completely inhibited germination of both varieties. Thus, in circumstances where both varieties are present in a soil seedbank, var. vernalis could be expected to establish in more challenging conditions, where moisture is limited and salinity is 'moderate to high', implying that it is a more serious threat for invasive weed in conditions where crop plants are already challenged.

Endolithic microbial habitats as refuges for life in polyextreme environment of the Atacama Desert.

The extremely harsh conditions of hyperarid deserts are a true challenge for microbial life. Microorganisms thriving in such polyextreme environments are fascinating as they can tell us more about life, its strategies and its boundaries than other groups of organisms. The Atacama Desert (North Chile) holds two world records of extreme environmental characteristics: the lowest rainfall and greatest surface ultraviolet radiation and total solar irradiance ever measured on Earth. Despite these limiting conditions for life, we recently identified several remarkable examples of endolithic habitats colonized by phototrophic and heterotrophic microorganisms in the hyperarid core of the Atacama Desert.

Genomic Understanding of an Infectious Brain Disease from the Desert.

Rhinocladiella mackenziei accounts for the majority of fungal brain infections in the Middle East, and is restricted to the arid climate zone between Saudi Arabia and Pakistan. Neurotropic dissemination caused by this fungus has been reported in immunocompromised, but also immunocompetent individuals. If untreated, the infection is fatal. Outside of humans, the environmental niche of R. mackenziei is unknown, and the fungus has been only cultured from brain biopsies. In this paper, we describe the whole-genome resequencing of two R. mackenziei strains from patients in Saudi Arabia and Qatar. We assessed intraspecies variation and genetic signatures to uncover the genomic basis of the pathogenesis, and potential niche adaptations. We found that the duplicated genes (paralogs) are more susceptible to accumulating significant mutations. Comparative genomics with other filamentous ascomycetes revealed a diverse arsenal of genes likely engaged in pathogenicity, such as the degradation of aromatic compounds and iron acquisition. In addition, intracellular accumulation of trehalose and choline suggests possible adaptations to the conditions of an arid climate region. Specifically, protein family contractions were found, including short-chain dehydrogenase/reductase SDR, the cytochrome P450 (CYP) (E-class), and the G-protein ß WD-40 repeat. Gene composition and metabolic potential indicate extremotolerance and hydrocarbon assimilation, suggesting a possible environmental habitat of oil-polluted desert soil.

Exertional Heat Illness Resulting in Acute Liver Failure and Liver Transplantation.

Heat illness remains a large medical burden for militaries around the world. Mitigating the incidence as well as the complications of heat illness must remain on the forefront of operational planning when operating in hot environments. We report the case of a 27-year-old male U.S. Marine who sustained a heat-related illness resulting in fulminant liver failure and permanent disability. The patient was transferred from the field to a civilian hospital. On hospital day 5, liver failure was identified. The patient was transferred to a transplant center, where he successfully received a liver transplant.

Population decline is linked to migration route in the Common Cuckoo.

Migratory species are in rapid decline globally. Although most mortality in long-distance migrant birds is thought to occur during migration, evidence of conditions on migration affecting breeding population sizes has been completely lacking. We addressed this by tracking 42 male Common Cuckoos from the rapidly declining UK population during 56 autumn migrations in 2011-14. Uniquely, the birds use two distinct routes to reach the same wintering grounds, allowing assessment of survival during migration independently of origin and destination. Mortality up to completion of the Sahara crossing (the major ecological barrier encountered in both routes) is higher for birds using the shorter route. The proportion of birds using this route strongly correlates with population decline across nine local breeding populations. Knowledge of variability in migratory behaviour and performance linked to robust population change data may therefore be necessary to understand population declines of migratory species and efficiently target conservation resources.

Impacts of ridge-furrow rainfall concentration systems and mulches on corn growth and yield in the semiarid region of China.

BACKGROUND: Plastic-covered ridge-furrow farming systems for rainfall concentration (RC) improve the water availability for crops and increase the water use efficiency (WUE), thereby stabilizing high yields. In this study, we optimized the mulching patterns for RC planting to mitigate the risks of drought during crop production in semiarid agricultural areas. We conducted a 4-year field study to determine the RC effects on corn production of mulching in furrows with 8% biodegradable films (RCSB ), liquid film (RCSL ), bare furrow (RCSN ) and conventional flat (CF) farming. RESULTS: We found that RC significantly (P > 0.05) increased the soil moisture in the top 0-100 cm layer and the topsoil temperature (0-20 cm) during the corn-growing period. Mulching with different materials in planting furrows further improved the rain-harvesting, moisture-retaining and yield-increasing effects of RC planting. Compared with CF, the 4-year average total dry matter amount per plant for RCSB , RCSL and RCSN treatments increased by 42.1%, 30.8% and 17.2%, respectively. The grain yield increased by 59.7%, 53.4% and 32.6%, respectively. CONCLUSION: Plastic-covered ridge and furrow mulched with biodegradable film and liquid film is recommended for use in the semiarid Loess Plateau of China to alleviate the effects of drought on crop production. © 2015 Society of Chemical Industry.

Dietary nitrate reduces the O2 cost of desert marching but elevates the rise in core temperature.

PURPOSE: Dietary nitrate (NO3 (-)) supplementation reduces the O2 cost of fixed-workload tasks performed in temperate environments but has not been examined in the heat. If this effect were retained it could reduce heatstroke risk in military personnel that are deployed for desert combat. METHODS: Nine men completed three 45 min loaded battle marches at a standard cadence (4.83 km h(-1)/1.5 % grade) while wearing full combat gear [BDU, boots, body armor (8 kg), NBC suit] and carrying a loaded rucksack (16 kg). The 1st March (FAM) commenced in a temperate environment. The 2nd and 3rd commenced in simulated dry desert conditions (41 °C/20 % RH) and required subjects to ingest the beetroot juice equivalent of 8.4 mmol NO3 (-) (BRJ) or a NO3 (-) depleted placebo (PLA) for 6 days prior. VO2, VCO2, V E, core (T re), skin (T sk), and mean body (T b) temperatures, HR, and physiological strain index (PSI) were measured continuously. Thermal sensation, generalized discomfort, and perceived exertion (RPE) were measured at 5 min intervals. Heat storage (HS) was calculated. Blood markers of gastrointestinal permeability (TNF, Il-6, HO-1) were measured before and after exercise. RESULTS: VO2 in BRJ was lower than PLA from 1 to 12; 16 to 26; and 29 to 45 min of exercise (p < 0.05). VCO2 in BRJ was lower than PLA from 1 to 12 min (p < 0.05). V E in BRJ was lower than PLA from 1 to 20 min of exercise (p < 0.05). T re and T b in BRJ exceeded PLA from 16 to 45 min (p < 0.05). TNF, Il-6, and HO-1 were reduced in BRJ (p < 0.05) while HR, PSI, Tsk, and HS were not altered (p > 0.05). Thermal sensation, generalized discomfort, and RPE were elevated in BRJ from 40 to 45, 25 to 45, and 10 to 45 min, respectively (p < 0.01). CONCLUSION: Metabolic efficiency was improved in BRJ. Paradoxically, body temperatures rose more. This was not due to gut permeability. Therefore, we speculate that based on elimination of other possibilities, blood redistribution from skin to skeletal muscle may have contributed to impaired heat exchange.

[Changes in blood gas parameters of heatstroke rats in dry-heat environment of desert].

OBJECTIVE: To investigate the changes in characteristics of blood gas analysis of heatstroke rats residing in dry-heat environment of desert, and to provide a theoretical reference for its treatment in clinic. METHODS: Forty-eight male Sprague-Dawley ( SD ) adult rats under anesthesia were divided into six groups by random number table, with 8 rats in each group: namely mild, moderate, severe heatstroke groups and their corresponding control groups. The rats were placed in an artificial chamber with simulated desert dry-heat environment ( temperature 41 centigrade, humidity 10% ) for about 70, 110, 145 minutes, respectively, to reproduce mild, moderate, severe heatstroke models. The rats in control groups were placed in a normothermic environment for corresponding duration. Abdominal aorta blood of each group was collected for blood gas analysis, and electrolytes were determined by a portable blood gas analyzer. RESULTS: (1) Arterial partial pressure of carbon dioxide ( PaCO(2) ) in mild heatstroke group was increased to ( 45.64±8.19 ) mmHg ( 1 mmHg = 0.133 kPa ), arterial oxygen saturation ( SaO(2) ) was decreased to 0.84±0.08, pH value was lowered to 7.36±0.11, showing that respiratory acid-base imbalance was resulted. Base excess of extracellular fluid ( BEecf ) in moderate heatstroke group was decreased to ( -3.00±0.76 ) mmol/L, HCO(3)(-) was decreased to ( 19.39±1.89 ) mmol/L, and pH value was lowered to 7.21±0.07, indicating that metabolic acid-base imbalance was aggravated gradually. The changes in parameters in severe heatstroke group gradually became more serious, and a significant difference was found as compared with those of mild and moderate heatstroke groups ( PaCO(2): F = 6.537, P = 0.006; SaO(2): F = 5.174, P = 0.015; pH value: F = 10.736, P = 0.001; BEecf: F = 67.136, P = 0.000; HCO(3)(-): F = 5.612, P = 0.011 ), manifesting an obvious combination of respiratory acidosis and metabolic acidosis, and a serious mixed acid-base disturbance was produced. (2) Compared with corresponding control groups, hemoglobin ( Hb ) was significantly increased in moderate heatstroke group ( g/L: 15.31±1.84 vs. 13.28±0.94, t = 2.791, P = 0.014 ), Hb and hematocrit ( HCT ) in severe heatstroke group were significantly increased [ Hb ( g/L ): 16.59±2.52 vs. 13.42±1.15, t = 3.224, P = 0.006; HCT: ( 53.50±6.63 )% vs. ( 45.50±4.47 )%, t = 2.828, P = 0.013 ], showing that the degree of dehydration was aggravated gradually from mild to serious degree. (3) Serum sodium content in mild heatstroke group was normal ( t = 0.665, P = 0.517 ), serum potassium content was lowered significantly ( t = -2.526, P = 0.024 ); serum sodium content in moderate heatstroke group was increased significantly ( t = 2.162, P = 0.048 ), serum potassium content was lowered significantly ( t = -5.458, P = 0.000 ); and serum sodium content in severe heatstroke group rose obviously ( U = 12.500, P = 0.038 ), and most of the rats showed hypokalemia, with a small proportion of rats showed obvious hyperkalemia ( U = 19.500, P = 0.195 ). CONCLUSIONS: Acidosis, electrolyte disturbance, respiratory failure and dehydration in heatstroke occurred in dry-heat environment of desert. It indicates that resuscitation should focus on correction of respiratory acidosis, with simultaneous correction of metabolic acidosis, and one should be alert to correct dehydration and electrolyte disturbance. During the moderate phase and the serious phase, correction of aggravated metabolic acidosis should be reinforced, and the prevention and treatment of the severe dehydration and electrolyte disturbance should be undertaken actively.

Desert dust is a risk factor for the incidence of acute myocardial infarction in Western Japan.

BACKGROUND: Recently, there has been increasing concern about adverse health effects of exposure to desert dust events. However, the association between dust and the incidence of ischemic heart diseases is unknown. The aim of the present study was to elucidate whether Asian dust (AD), a windblown sand dust originating from mineral soil in China and Mongolia, is associated with the incidence of acute myocardial infarction (AMI). METHODS AND RESULTS: We investigated the data regarding hospitalization because of AMI among 3068 consecutive patients from 4 AMI centers in Fukuoka, Japan, and data for AD from April 2003 to December 2010. We applied a time-stratified case-crossover design to examine the association between AD and the incidence of AMI. Using a conditional logistic regression analysis, we estimated the odds ratios of AMI associated with AD after controlling for ambient temperature and relative humidity. The occurrence of AD events 0 to 4 days before the day of admission was significantly associated with the incidence of AMI. In particular, the occurrence of AD 4 days before admission was significantly associated with the onset of AMI. CONCLUSIONS: These data suggest that exposure to AD a few days before symptom onset is associated with the incidence of AMI.