RESUMO
Climate warming, land use change, and altered fire regimes are driving ecological transformations that can have critical effects on Earth's biota. Fire refugia-locations that are burned less frequently or severely than their surroundings-may act as sites of relative stability during this period of rapid change by being resistant to fire and supporting post-fire recovery in adjacent areas. Because of their value to forest ecosystem persistence, there is an urgent need to anticipate where refugia are most likely to be found and where they align with environmental conditions that support post-fire tree recruitment. Using biophysical predictors and patterns of burn severity from 1180 recent fire events, we mapped the locations of potential fire refugia across upland conifer forests in the southwestern United States (US) (99,428 km2 of forest area), a region that is highly vulnerable to fire-driven transformation. We found that low pre-fire forest cover, flat slopes or topographic concavities, moderate weather conditions, spring-season burning, and areas affected by low- to moderate-severity fire within the previous 15 years were most commonly associated with refugia. Based on current (i.e., 2021) conditions, we predicted that 67.6% and 18.1% of conifer forests in our study area would contain refugia under moderate and extreme fire weather, respectively. However, potential refugia were 36.4% (moderate weather) and 31.2% (extreme weather) more common across forests that experienced recent fires, supporting the increased use of prescribed and resource objective fires during moderate weather conditions to promote fire-resistant landscapes. When overlaid with models of tree recruitment, 23.2% (moderate weather) and 6.4% (extreme weather) of forests were classified as refugia with a high potential to support post-fire recruitment in the surrounding landscape. These locations may be disproportionately valuable for ecosystem sustainability, providing habitat for fire-sensitive species and maintaining forest persistence in an increasingly fire-prone world.
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Incêndios , Traqueófitas , Ecossistema , Florestas , Árvores , Tempo (Meteorologia)RESUMO
The western United States is projected to experience more frequent and severe wildfires in the future due to drier and hotter climate conditions, exacerbating destructive wildfire impacts on forest ecosystems such as tree mortality and unsuccessful post-fire regeneration. While empirical studies have revealed strong relationships between topographical information and plant regeneration, ecological processes in ecosystem models have either not fully addressed topography-mediated effects on the probability of plant regeneration, or the probability is only controlled by climate-related factors, for example, water and light stresses. In this study, we incorporated seedling survival data based on a planting experiment in the footprint of the 2011 Las Conchas Fire into the Photosynthesis and EvapoTranspiration (PnET) extension of the LANDIS-II model by adding topographic and an additional climatic variable to the probability of regeneration. The modified algorithm included topographic parameters such as heat load index and ground slope and spring precipitation. We ran simulations on the Las Conchas Fire landscape for 2012-2099 using observed and projected climate data (i.e., Representative Concentration Pathway 4.5 and 8.5). Our modification significantly reduced the number of regeneration events of three common southwestern conifer tree species (piñon, ponderosa pine, and Douglas-fir), leading to decreases in aboveground biomass, regardless of climate scenario. The modified algorithm decreased regeneration at higher elevations and increased regeneration at lower elevations relative to the original algorithm. Regenerations of three species also decreased in eastern aspects. Our findings suggest that ecosystem models may overestimate post-fire regeneration events in the southwest United States. To better represent regeneration processes following wildfire, ecosystem models need refinement to better account for the range of factors that influence tree seedling establishment. This will improve model utility for projecting the combined effects of climate and wildfire on tree species distributions.
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Incêndios , Traqueófitas , Ecossistema , Florestas , Sudoeste dos Estados UnidosRESUMO
Coccidioidomycosis is a fungal infection endemic to the Southwestern United States. Extrapulmonary Coccidioides immitis infections are uncommon and occur more frequently in immunocompromised individuals. There is often a delay in diagnosis and treatment due to the chronic, indolent nature of these infections. The clinical presentation is often nonspecific, and includes joint pain, erythema, or localized swelling. Therefore, these infections may only be identified after initial treatment failure and further workup is pursued. The majority of reported cases of coccidioidomycosis involving the knee have had intra-articular involvement or extension. This report describes a rare case of peri-articular Coccidioides immitis abscess of the knee that does not communicate with the joint in a healthy patient. This case illustrates the low threshold needed for additional testing, such as fluid or tissue sampling of joint-related fluid collections if the etiology is unclear. A high index of suspicion is prudent to avoid diagnostic delay, particularly for individuals who either reside in or travel to endemic areas.
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Coccidioidomicose , Humanos , Coccidioidomicose/diagnóstico , Coccidioidomicose/tratamento farmacológico , Coccidioidomicose/microbiologia , Diagnóstico Tardio , Coccidioides , Articulação do JoelhoRESUMO
We determine the presence and diversity of rhinoviruses in nasopharyngeal swab samples from 248 individuals who presented with influenza-like illness (ILI) at a university clinic in the Southwest United States between October 1, 2020 and March 31, 2021. We identify at least 13 rhinovirus genotypes (A11, A22, A23, A25, A67, A101, B6, B79, C1, C17, C36, and C56, as well a new genotype [AZ88**]) and 16 variants that contributed to the burden of ILI in the community. We also describe the complete capsid protein gene of a member (AZ88**) of an unassigned rhinovirus A genotype.
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Infecções por Enterovirus , Infecções por Picornaviridae , Infecções Respiratórias , Viroses , Humanos , Rhinovirus/genética , Infecções Respiratórias/epidemiologia , Universidades , Infecções por Picornaviridae/epidemiologia , GenótipoRESUMO
Coccidioides immitis and Coccidioides posadasii are the etiological agents of coccidioidomycosis (Valley fever [VF]). Disease manifestation ranges from mild pneumonia to chronic or extrapulmonary infection. If diagnosis is delayed, the risk of severe disease increases. In this report, we investigated the intersection of pathogen, host, and environment for VF cases in Northern Arizona (NAZ), where the risk of acquiring the disease is much lower than in Southern Arizona. We investigated reported cases and assessed pathogen origin by comparing genomes of NAZ clinical isolates to isolates from other regions. Lastly, we surveyed regional soils for presence of Coccidioides. We found that cases of VF increased in NAZ in 2019, and Coccidioides NAZ isolates are assigned to Arizona populations using phylogenetic inference. Importantly, we detected Coccidioides DNA in NAZ soil. Given recent climate modeling of the disease that predicts that cases will continue to increase throughout the region, and the evidence presented in this report, we propose that disease awareness outreach to clinicians throughout the western United States is crucial for improving patient outcomes, and further environmental sampling across the western U.S. is warranted. IMPORTANCE Our work is the first description of the Valley fever disease triangle in Northern Arizona, which addresses the host, the pathogen, and the environmental source in the region. Our data suggest that the prevalence of diagnosed cases rose in 2019 in this region, and some severe cases necessitate hospitalization. We present the first evidence of Coccidioides spp. in Northern Arizona soils, suggesting that the pathogen is maintained in the local environment. Until disease prevention is an achievable option via vaccination, we predict that incidence of Valley fever will rise in the area. Therefore, enhanced awareness of and surveillance for coccidioidomycosis is vital to community health in Northern Arizona.
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Coccidioidomicose , Humanos , Estados Unidos , Coccidioidomicose/epidemiologia , Arizona/epidemiologia , Filogenia , Incidência , SoloRESUMO
The European grapevine (Vitis vinifera L.) has been cultivated in North America for about 500 years. One of the major limitations to its culture is the powdery mildew (PM) fungus, Erysiphe necator Schw. This study reports on the most extensive screening of Vitis species from the southwestern United States and northern Mexico for resistance to PM, testing 147 accessions of 13 Vitis species. In addition, Vitis vinifera cv. Carignane, a highly susceptible wine grape cultivar, was used as a reference to evaluate the effect of the inoculum 14 days postinoculation. Inoculation was done with a vacuum-operated settling tower using a broadly virulent isolate of E. necator, the C-strain. Resistant accessions (nine), moderately susceptible accessions (39), and highly susceptible accessions (99) were detected. The resistant accessions were then inoculated with an additional fungal isolate, e1-101, and they retained their resistance. Vitis species susceptibility was not associated with a North-South gradation, but Western species were more susceptible than Midwestern and Eastern species. All five of the V. monticola accessions were susceptible, as were the accessions of V. treleasei. The species V. acerifolia, V. candicans, V. cinerea, and V. × doaniana had significantly more resistant to moderately susceptible accessions compared with V. arizonica, V. berlandieri, V. californica, V. × champinii, V. girdiana, V. riparia, and V. rupestris, which had relatively more susceptible accessions than the other species. This research identified new sources of PM resistance in Vitis from the southwestern United States that could be incorporated into PM resistance breeding programs throughout the world.
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Ascomicetos , Vitis , Resistência à Doença , Doenças das Plantas , Sudoeste dos Estados UnidosRESUMO
Grasslands managed for grazing are the largest land-use category globally, with a significant proportion of these grasslands occurring in semiarid and arid regions. In such dryland systems, the effect of grazing on native plant diversity has been equivocal, some studies suggesting that grazing reduces native plant diversity, others that grazing increases or has little impact on diversity. One impediment toward generalizing grazing effects on diversity in this region is that high levels of interannual variation in precipitation may obfuscate vegetative response patterns. By analyzing a long-term data set collected over a 20-yr period in a semiarid grassland, we explicitly evaluated the role of climate in regulating the effect of cattle grazing on plant communities, finding that climate interacted with grazing intensity to shape grassland communities. Community composition of plots that were intensively grazed varied considerably in response to climatic variation and native species richness was low relative to ungrazed and moderately grazed plots. Following a severe drought in 2002, exotic species richness rapidly increased in the high-intensity grazing plots. While this pattern was mirrored in the other treatments, exotic species richness increased to a greater extent and was slower to return to pre-drought levels in the high-intensity grazing plots. Overall, moderate grazing, even compared to grazing cessation, stabilized grassland communities through time, increased resilience to drought, and maintained the highest levels of native plant diversity and lowest levels of exotic diversity. These findings suggest that grazing, at moderate levels, may support grassland resilience to climate change in semiarid regions. However, grazing that exceeds tolerances, particularly in combination with extreme climatic events, like drought, can alter plant composition over relatively long timescales and possibly increase invasibility by nonnative species.
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Secas , Pradaria , Animais , Biodiversidade , Bovinos , Mudança Climática , PlantasRESUMO
PURPOSE: Spina Bifida (SB) is a congenital defect of the neural tube resulting in motor and sensory defects and frequently includes insensate skin on the buttocks and feet which are innervated by sacral nerves. For those living in hot climates such as the Southwestern United States, environmental surfaces reach temperatures throughout June-September that cause thermal burns. The objective of this novel case series was to evaluate the circumstances associated with environmental buttocks burns in children with SB who attend the District Medical Group Children's Rehabilitative Services Myelomeningocele (MM) Planning clinic in Phoenix, AZ. METHODS: Nine children and adolescents with SB and a history of environmental buttocks burns were identified through participation in the National Spina Bifida Patient Registry at District Medical Group Children's Rehabilitative Services Myelomeningocele Planning Clinic. Parents and patients were interviewed about the burn circumstances, charts were reviewed, and information was gathered from the NSBPR including level of function and ambulation status. RESULTS: Most of the patients were found to be of emerging independent ages (average age 10 years) and were not with their parents at the time of the burn. All had myelomeningocele (MM), almost all were community ambulators, and all had mid lumbar, low lumbar or sacral level function. There were no non-ambulators. In addition, the majority were wearing incontinence products. CONCLUSIONS: Children and adolescents with MM who are community ambulators, of an emerging independent age, and live in hot climates are at risk of environmental buttocks burns. Enhanced education in environmental thermal burn prevention is important. This education should be particularly focused on the child as they spend more time in settings without their parents. In addition, this enhanced education should extend to those who support the child or teen such as teachers, coaches, family and friends.
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Queimaduras/etiologia , Nádegas/lesões , Meio Ambiente , Meningomielocele/complicações , Disrafismo Espinal/complicações , Adolescente , Criança , Feminino , Humanos , Masculino , Sudoeste dos Estados UnidosRESUMO
PURPOSE OF REVIEW: This review summarizes recent literature examining exposure to environmental metals in rural areas of the southwestern/mountain west region of the United States focusing on the range of exposures and exposure pathways unique to this region. RECENT FINDINGS: Recent studies (2013-2018) indicated that exposures to arsenic (As), uranium (U), and cadmium (Cd) were the most commonly quantified metals in the study area. One or more of these three metals was analyzed in each study reviewed. SUMMARY: The current review draws attention to the variety of exposure assessment methods, analytical tools, and unique non-occupational exposure pathways in this region. The reviewed studies identified potential sources of metals exposure including regulated and unregulated drinking water, particulate matter, and food items, and provided information about the levels of exposures experienced by populations through a variety of exposure assessment methods including spatial analysis methodologies. The findings suggest that exposure assessment methods could be further integrated with population studies to assess health effects of environmental metals exposure through pathways unique to Southwestern and Mountain West U.S.
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PREMISE OF THE STUDY: Phenology is the study of biological life cycle events, such as flowering and migration. Climate patterns can alter these life history events, having ecosystem-wide ramifications. For example, warmer springs are associated with earlier leaf-out for many species, impacting species interactions and growing-season carbon dynamics. While phenological research has been conducted extensively in temperate regions, relatively little is known about the phenological responses in arid and semi-arid regions. METHODS: In this study we looked at the flowering phenology of a keystone species in the Sonoran Desert, the saguaro cactus (Carnegiea gigantea). The timing and abundance of flowering was observed on 151 individuals for 10 years at a site near Tucson, Arizona, USA. Using six phenological traits, we explored the relationship between saguaro size and flowering and the climatic drivers of flowering. KEY RESULTS: Our analyses demonstrated how the calculation of phenological traits at the individual versus the population level can yield differing responses to climate variability, suggesting that not all studies examining the same trait (e.g., first day of bloom) are directly comparable. We found that larger cacti began flowering earlier, flowered for longer, and produced more flowers. Warmer temperatures were correlated with advanced onset and higher bloom yields, while increased precipitation appeared to delay onset and reduce bloom yields. CONCLUSIONS: Given that climate models predict that the Southwestern USA will become increasingly warmer with more variable precipitation, saguaros may begin flowering earlier in the season and flower more intensely, which could impact pollen availability and population dynamics.
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Cactaceae/fisiologia , Clima , Flores/fisiologia , Arizona , Tamanho Corporal , Modelos Lineares , Estações do Ano , Tempo (Meteorologia)RESUMO
Unionid mussels are considered sensitive to salinity and there is growing concern in arid and semi-arid regions that declining flows coupled with anthropogenic impacts are amplifying natural salinity levels. In this study, we tested the effects of varying salinity concentrations (3.0, 4.0, 5.0, 6.0, 7.0 and 10.0 ppt NaCl) on survival of adult Popenaias popeii, (Texas Hornshell). This species occurs in the Rio Grande basin of Texas and northern Mexico, an arid to semi-arid stream plagued by salinization, and was recently listed as Endangered under the U.S. Endangered Species Act. We performed 2, 4, and 10-day toxicity tests on individuals from two disjunct populations: Laredo, TX, and the Lower Canyons of the Rio Grande near Big Bend National Park. We found no significant differences in LC50 estimates between populations at 96-hrs or 10-days but significant differences in TUD50s at 5 ppt between populations, which indicates that tolerance does not vary but sensitivity may between these populations. Overlaying LC50 estimates at 10-days for both populations on plots of salinity (ppt) measured over time, we show parts of the Rio Grande periodically approach or exceed 4.0 ppt, indicating these reaches are becoming unsuitable for P. popeii and populations within them at risk.
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Conservação dos Recursos Naturais , Tolerância ao Sal , Unionidae/fisiologia , Purificação da Água , Animais , Água Subterrânea/química , Dose Letal Mediana , México , Texas , Testes de Toxicidade , Poluentes Químicos da ÁguaRESUMO
Survivors of intimate partner violence (IPV) have an elevated risk for negative sexual health outcomes, including HIV and sexually transmitted infection (STI). Given the unique risk contexts for survivors, there is a need for effective sexual health interventions that take into account the imbalances of power for women who are survivors of IPV. Toward the aim of informing contextually relevant intervention approaches, this article describes women's strategies toward maintaining their sexual health in the context of violent, controlling relationships. Strategies are examined across women's healing process. Data were collected through semi-structured, in-person interviews with women who had experienced IPV ( N = 28). Participants had a wide range of negative sexual health outcomes and commonly used an analogy of a journey to describe their healing. Throughout these journeys, women gained more confidence and ownership over their sexuality. Themes centered around enhanced self-acceptance, ownership of personal sexuality, and readiness for desirable sexual partnerships.
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Violência por Parceiro Íntimo/psicologia , Parceiros Sexuais/psicologia , Sexualidade/psicologia , Sobreviventes/psicologia , Adaptação Psicológica , Adulto , Feminino , Humanos , Entrevistas como Assunto , Pessoa de Meia-Idade , Fatores de Risco , Comportamento Sexual/psicologia , Sudoeste dos Estados Unidos , Adulto JovemRESUMO
PREMISE OF THE STUDY: Astragalus sect. Humillimi is distributed across the southwestern United States and contains two endangered taxa, A. cremnophylax var. cremnophylax and A. humillimus. The former was originally described from the South Rim of the Grand Canyon. Analysis of individuals discovered on the North Rim of the Grand Canyon yielded some evidence that the population represented a distinct species. To enable effective conservation, we clarify the group's taxonomy and characterize the genetic diversity of A. cremnophylax and A. humillimus. METHODS: We used AFLPs to genotype most species in sect. Humillimi, focusing on the two endangered forms. We examined patterns of genetic diversity using complementary analytical approaches. KEY RESULTS: Our results demonstrate that North Rim populations group with A. c. var. cremnophylax. We found low levels of genetic diversity at certain localities and strong differentiation among populations. Astragalus humillimus, which has suffered recent and severe population declines, exhibits weak differentiation among and low diversity within populations. CONCLUSIONS: Our results clarify the taxonomy of sect. Humillimi and define the boundaries of A. c. var. cremnophylax, which is shown to inhabit both rims of the Grand Canyon. This clarification, and detailed analysis of genetic variation within both endangered taxa, may advance ongoing efforts to conserve these taxa. Our results suggest that range-wide genetic analysis of A. humillimus may inform recovery strategies for this taxon.
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Astrágalo/genética , Conservação dos Recursos Naturais , Variação Genética , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Astrágalo/classificação , Genótipo , Sudoeste dos Estados UnidosRESUMO
Freshwater resources in arid and semi-arid regions are in extreme demand, which creates conflicts between needs of humans and aquatic ecosystems. The Rio Grande basin in the southwestern United States and northern Mexico exemplifies this issue, as much of its aquatic biodiversity is in peril as a result of human activities. Unionid mussels have been disproportionately impacted, though the specific factors responsible for their decline remain largely unknown. This is problematic because the Rio Grande basin harbors one federally endangered unionid mussel (Popenaias popeii, Texas Hornshell) plus two other mussel species (Potamilus metnecktayi, Salina Mucket; and Truncilla cognata, Mexican Fawnsfoot), which are also being considered for listing under the U.S. Endangered Species Act. To date, surveys for these species have not corrected for variability in detection so current range estimates may be inaccurate. Using single occupancy-modeling to estimate detection and occupancy at 115 sites along ~800 river kilometers of the Rio Grande in Texas, we found that detection probabilities were relatively high, indicating that our survey design was efficient. In contrast, the estimated occupancy was low, indicating that our focal species were likely rare within the Rio Grande drainage. In general, the predicted occupancy of our focal species was low throughout their respective ranges, indicating possible range declines. A comparison of currently occupied ranges to presumptive ranges underscores this point. The best-approximating models indicated that occupancy was influenced by habitat, water quantity and quality, and proximity to large-scale human activities, such as dams and major urban centers. We also discuss a series of conservation options that may not only improve the long-term prognosis of our focal species but also other aquatic taxa.
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Conservação dos Recursos Naturais , Ecossistema , Espécies em Perigo de Extinção , Unionidae/fisiologia , Animais , Biodiversidade , Rios/química , Texas , Poluentes Químicos da Água/análiseRESUMO
PURPOSE OF REVIEW: This review summarizes the recent epidemiologic literature examining environmental exposures and health outcomes in rural, minority populations in the southwestern and mountain west region of the United States identifying areas requiring further data and research. RECENT FINDINGS: Recent studies (2012-2017) in this region have primarily focused on arsenic exposure (n=10 studies) with similar results reported across populations in this region. Associations between arsenic and cadmium were reported for cardiovascular and kidney disease, type II diabetes, cognitive function, hypothyroidism, and increased prevalence and mortality for lung and other cancers. Also in this review are studies of exposure to particulate matter, environmental tobacco smoke, pesticides and fungicides, heat and ozone. SUMMARY: Although small, the current literature identified in this review report consistent adverse health outcomes associated with particulate matter, arsenic, cadmium, and other exposures among rural, minority populations in the southwest/mountain west region of the U.S. This literature provides important insight into the environmental exposures and health effects experienced by the rural populations in these regions. Additional studies that identify sources of environmental exposure are needed. Greater representation of the rural and minority populations from this region into large health studies also remains a need.
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Bubonic plague (Yersinia pestis) is a deadly zoonosis with black-tailed prairie dogs (Cynomys ludovicianus) as a reservoir host in the United States. Systemic insecticides are a promising means of controlling the vectors, Oropsylla spp. fleas, infesting these prairie dogs, subsequently disrupting the Y. pestis cycle. The objective of this study was to conduct a field trial evaluating the efficacy of a grain rodent bait containing fipronil (0.005%) against fleas infesting prairie dogs. The study was performed in Larimer County, CO, where bait was applied to a treatment area containing a dense prairie dog population, three times over a three-week period. Prairie dogs were captured and combed for fleas during four study periods (pre-, mid-, 1st post-, and 2nd post-treatment). Results indicated the use of bait containing fipronil significantly reduced flea burden. The bait containing fipronil was determined to reduce the mean number of fleas per prairie dog >95% for a minimum of 52 days post-initial treatment application and 31 days post-final treatment application. These results suggest the potential for this form of treatment to reduce flea population density on prairie dogs, and subsequently plague transmission, among mammalian hosts across the United States and beyond.
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Infestações por Pulgas/prevenção & controle , Pirazóis , Sciuridae/parasitologia , Sifonápteros , Animais , Peste , Doenças dos Roedores , Yersinia pestisRESUMO
While many health literacy assessments exist, this area of research lacks an instrument that isolates and reflects the four components driving this concept (abilities to find, understand, use, and communicate about health information). The purpose of this study was to determine what abilities comprise the first component, how a patient finds health information. Low ( n = 13) and adequate ( n = 14) health literacy patients, and health professionals ( n = 10) described their experiences when looking for health information and the skills they employed to complete these tasks. Major skills/themes elicited included knowing when to search, credibility assessments, finding text and numerical information, interpersonal seeking, technology and online search, and spatial navigation. Findings from this study suggest that each of the dimensions included in the definition of health literacy warrants specific attention and assessment. Given identification of the skills comprising each dimension, interventions targeting deficits across health literacy dimensions could be developed to improve patient health.
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Informação de Saúde ao Consumidor/métodos , Informação de Saúde ao Consumidor/normas , Letramento em Saúde , Comportamento de Busca de Informação , Adulto , Escolaridade , Humanos , Internet , Pessoa de Meia-IdadeRESUMO
Because coccidioidomycosis death rates vary by region, we reanalyzed coccidioidomycosis-associated mortality in the United States by race/ethnicity, then limited analysis to Arizona and California. Coccidioidomycosis-associated deaths were shown to increase among African-Americans but decrease among Native Americans and Hispanics. Separately, in a Native American cohort, diabetes co-varied with coccidioidomycosis-associated death.
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Coccidioidomicose/mortalidade , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Arizona/epidemiologia , California/epidemiologia , Criança , Pré-Escolar , Coccidioidomicose/etnologia , Coccidioidomicose/história , Feminino , Geografia , História do Século XX , História do Século XXI , Humanos , Indígenas Norte-Americanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Estados Unidos/epidemiologia , Adulto JovemRESUMO
The integration of ecological niche modelling into phylogeographic analyses has allowed for the identification and testing of potential refugia under a hypothesis-based framework, where the expected patterns of higher genetic diversity in refugial populations and evidence of range expansion of nonrefugial populations are corroborated with empirical data. In this study, we focus on a montane-restricted cryophilic harvestman, Sclerobunus robustus, distributed throughout the heterogeneous Southern Rocky Mountains and Intermontane Plateau of southwestern North America. We identified hypothetical refugia using ecological niche models (ENMs) across three time periods, corroborated these refugia with population genetic methods using double-digest RAD-seq data and conducted population-level phylogenetic and divergence dating analyses. ENMs identify two large temporally persistent regions in the mid-latitude highlands. Genetic patterns support these two hypothesized refugia with higher genetic diversity within refugial populations and evidence for range expansion in populations found outside hypothesized refugia. Phylogenetic analyses identify five to six genetically divergent, geographically cohesive clades of S. robustus. Divergence dating analyses suggest that these separate refugia date to the Pliocene and that divergence between clades pre-dates the late Pleistocene glacial cycles, while diversification within clades was likely driven by these cycles. Population genetic analyses reveal effects of both isolation by distance (IBD) and isolation by environment (IBE), with IBD more important in the continuous mountainous portion of the distribution, while IBE was stronger in the populations inhabiting the isolated sky islands of the south. Using model-based coalescent approaches, we find support for postdivergence migration between clades from separate refugia.
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Aracnídeos/genética , Evolução Molecular , Genética Populacional , Refúgio de Vida Selvagem , Animais , Ecossistema , Variação Genética , Metagenômica , Filogenia , Sudoeste dos Estados UnidosRESUMO
The hyper-virulent emm59 genotype of invasive group A Streptococcus was identified in northern Arizona in 2015. Eighteen isolates belonging to a genomic cluster grouped most closely with recently identified isolates in New Mexico. The continued transmission of emm59 in the southwestern United States poses a public health concern.