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1.
Proc Natl Acad Sci U S A ; 121(31): e2321245121, 2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39008689

RESUMEN

Beef production has been identified as a significant source of anthropogenic greenhouse gas (GHG) emissions in the agricultural sector. United States and Canada account for about a quarter of the world's beef supply. To compare the GHG emission contributions of alternative beef production systems, we conducted a meta-analysis of 32 studies that were conducted between 2001 and 2023. Results indicated that GHG emissions from beef production in North America varied almost fourfold from 10.2 to 37.6 with an average of 21.4 kg CO2e/kg carcass weight (CW). Studies that considered soil C sequestration (C-seq) reported the highest mitigation potential in GHG emissions (80%), followed by growth enhancement technology (16%), diet modification (6%), and grazing management improvement (7%). Our study highlights the implications of using carbon intensity per economic activity (i.e., GHG emissions per monetary unit), compared to the more common metric of intensity on per weight of product basis (GHG emissions per kg CW) for comparisons across differentiated beef cattle products. While a positive association was found between the proportion of lifespan on grassland and the conventional weight-based indicator, grass-finished beef was found to have lower carbon intensity per economic activity than feedlot-finished beef. Our study emphasizes the need to incorporate land use and management effects and soil C-seq as fundamental aspects of beef GHG emissions and mitigation assessments.


Asunto(s)
Gases de Efecto Invernadero , Carne Roja , Animales , Bovinos , Gases de Efecto Invernadero/análisis , Carne Roja/economía , Canadá , Crianza de Animales Domésticos/métodos , Crianza de Animales Domésticos/economía , Estados Unidos , Agricultura/economía , Agricultura/métodos , Efecto Invernadero , Cambio Climático
2.
Nutrients ; 16(13)2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38999785

RESUMEN

Excessive vitamin A (VA) negatively impacts bone. Interactions between VA and vitamin D (VD) in bone health are not well-understood. This study used a traditional two-by-two factorial design. Pigs were weaned and randomized to four treatments (n = 13/group): -A-D, -A+D, +A-D, and +A+D for 3 and 5 wk. Serum, liver, kidney, adrenal glands, spleen, and lung were analyzed by ultra-performance LC. Growth was evaluated by weight measured weekly and BMD by DXA. Weights were higher in -A+D (18.1 ± 1.0 kg) and +A+D (18.2 ± 2.3 kg) at 5 wk than in -A-D (15.5 ± 2.1 kg) and +A-D (15.8 ± 1.5 kg). Serum retinol concentrations were 0.25 ± 0.023, 0.22 ± 0.10, 0.77 ± 0.12, and 0.84 ± 0.28 µmol/L; and liver VA concentrations were 0.016 ± 0.015, 0.0065 ± 0.0035, 2.97 ± 0.43, 3.05 ± 0.68 µmol/g in -A-D, -A+D, +A-D, and +A+D, respectively. Serum 25(OH)D3 concentrations were 1.5 ± 1.11, 1.8 ± 0.43, 27.7 ± 8.91, and 23.9 ± 6.67 ng/mL in -A-D, +A-D, -A+D, +A+D, respectively, indicating a deficiency in -D and adequacy in +D. BMD was highest in +D (p < 0.001). VA and the interaction had no effect on BMD. Dietary VD influenced weight gain, BMD, and health despite VA status.


Asunto(s)
Densidad Ósea , Deficiencia de Vitamina A , Vitamina A , Vitamina D , Animales , Densidad Ósea/efectos de los fármacos , Vitamina D/sangre , Porcinos , Vitamina A/sangre , Femenino , Masculino , Modelos Animales de Enfermedad , Hígado/metabolismo , Hígado/efectos de los fármacos , Suplementos Dietéticos
3.
Emerg Med Clin North Am ; 42(3): 541-550, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38925773

RESUMEN

Drowning is responsible for considerable morbidity and mortality worldwide, and it is estimated that 90% of drownings are preventable. Drowning is defined as "the process of experiencing respiratory impairment from submersion/immersion in liquid." Emergency providers should focus on airway management and rapid delivery of oxygen to interrupt the drowning process and improve patient outcomes. Patients with minimal or no symptoms do not require any specific diagnostic workup, aside from physical examination and 4 to 6 hours of observation prior to discharge. Patients with more severe symptoms may present with rales and foamy secretions, and should be managed with high-concentration oxygen and positive airway pressure.


Asunto(s)
Ahogamiento , Humanos , Ahogamiento/diagnóstico , Ahogamiento Inminente/terapia , Servicio de Urgencia en Hospital
4.
Cancer Discov ; : OF1-OF9, 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38867349

RESUMEN

Juvenile myelomonocytic leukemia (JMML) is a hematologic malignancy of young children caused by mutations that increase Ras signaling output. Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment, but patients with relapsed or refractory (advanced) disease have dismal outcomes. This phase II trial evaluated the safety and efficacy of trametinib, an oral MEK1/2 inhibitor, in patients with advanced JMML. Ten infants and children were enrolled, and the objective response rate was 50%. Four patients with refractory disease proceeded to HSCT after receiving trametinib. Three additional patients completed all 12 cycles permitted on study and continue to receive off-protocol trametinib without HSCT. The remaining three patients had progressive disease with two demonstrating molecular evolution by the end of cycle 2. Transcriptomic and proteomic analyses provided novel insights into the mechanisms of response and resistance to trametinib in JMML. ClinicalTrials.gov Identifier: NCT03190915. Significance: Trametinib was safe and effective in young children with relapsed or refractory JMML, a lethal disease with poor survival rates. Seven of 10 patients completed the maximum 12 cycles of therapy or used trametinib as a bridge to HSCT and are alive with a median follow-up of 24 months.

5.
iScience ; 27(6): 110068, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38872973

RESUMEN

Most cells in solid tumors are exposed to oxygen levels between 0.5% and 5%. We developed an approach that allows collection, processing, and evaluation of cancer and non-cancer cells under physioxia, while preventing exposure to ambient air. This aided comparison of baseline and drug-induced changes in signaling pathways under physioxia and ambient oxygen. Using tumor cells from transgenic models of breast cancer and cells from breast tissues of clinically breast cancer-free women, we demonstrate oxygen-dependent differences in cell preference for epidermal growth factor receptor (EGFR) or platelet-derived growth factor receptor beta (PDGFRß) signaling. Physioxia caused PDGFRß-mediated activation of AKT and extracellular regulated kinase (ERK) that reduced sensitivity to EGFR and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) inhibition and maintained PDGFRß+ epithelial-mesenchymal hybrid cells with potential cancer stem cell (CSC) properties. Cells in ambient air displayed differential EGFR activation and were more sensitive to targeted therapies. Our data emphasize the importance of oxygen considerations in preclinical cancer research to identify effective drug targets and develop combination therapy regimens.

6.
Nursing ; 54(7): 26-32, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38913923

RESUMEN

ABSTRACT: Drowning is the process of respiratory impairment from immersion or submersion in a liquid. Worldwide, approximately 360,000 deaths annually can be attributed to drowning. Morbidity and mortality are a result of hypoxia, so the focus during resuscitation should be on airway management and optimizing oxygenation. This article describes several drowning scenarios and discusses appropriate response and treatment algorithms.


Asunto(s)
Ahogamiento , Humanos , Terminología como Asunto , Manejo de la Vía Aérea/métodos , Algoritmos
7.
Angew Chem Int Ed Engl ; : e202407281, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38779787

RESUMEN

Catalytic olefin hydroamination reactions are some of the most atom-economical transformations that bridge readily available starting materials-olefins and high-value-added amines. Despite significant advances in this field over the last two decades, the formal hydroamination of nonactivated aromatic compounds remains an unsolved challenge. Herein, we report the extension of olefin hydroamination to aromatic π-systems by using arenophile-mediated dearomatization and Cu-catalysis to perform 1,2-hydroamination on nonactivated arenes. This strategy was applied to a variety of substituted arenes and heteroarenes to provide general access to structurally complex amines. We conducted DFT calculations to inform mechanistic understanding and rationalize unexpected selectivity trends. Furthermore, we developed a practical, scalable desymmetrization to deliver enantioenriched dearomatized products and enable downstream synthetic applications. We ultimately used this dearomative strategy to efficiently synthesize a collection of densely functionalized small molecules.

8.
Med Clin North Am ; 108(4): 641-653, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38816108

RESUMEN

Atopic dermatitis (AD) is a common, chronic relapsing, and remitting inflammatory skin disease that is characterized by erythematous, scaly, and pruritic lesions often located over the flexural surfaces. Treatment goals of AD include the reduction of itching and burning, as well as the reduction of skin changes. Treatment of AD includes emollients and skin care, topical therapies including topical corticosteroids and steroid-sparing therapies, systemic therapies, and phototherapy.


Asunto(s)
Dermatitis Atópica , Humanos , Corticoesteroides/uso terapéutico , Corticoesteroides/administración & dosificación , Dermatitis Atópica/tratamiento farmacológico , Dermatitis Atópica/terapia , Fármacos Dermatológicos/uso terapéutico , Fármacos Dermatológicos/administración & dosificación , Emolientes/uso terapéutico , Emolientes/administración & dosificación , Fototerapia/métodos , Cuidados de la Piel/métodos
9.
J Nutr ; 2024 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-38797483

RESUMEN

BACKGROUND: Vitamin A (VA) deficiency and excess negatively affect development, growth, and bone health. The World Health Organization's standard of care for xerophthalmia due to VA deficiency, is 3 high-dose VA supplements of 50,000-200,000 IU, based on age, which may cause hypervitaminosis A in some individuals. OBJECTIVES: This study measured VA status following 3 VA doses in 2 piglet studies. METHODS: In Study 1, 5 groups of piglets (n = 10/group) were weaned 10 d postbirth to VA-free feed and orally administered 0; 25,000; 50,000; 100,000; or 200,000 IU VA ester on days 0, 1, and 7. On days 14 and 15, the piglets underwent the modified relative dose-response (MRDR) test for VA deficiency, and were killed. Tissues were collected for high-pressure liquid chromatography analysis. Study 2 used the same design in 3 groups (n = 13/group) weaned at 16 d and administered 0; 25,000; and 200,000 IU doses. RESULTS: In Study 1 (final weight: 3.6 ± 0.7 kg), liver VA concentration was hypervitaminotic in 40%, 90%, and 100% of 50,000; 100,000; and 200,000 IU groups, respectively. The 25,000 IU group was 100% adequate, and the placebo group was 40% deficient. In Study 2 (final weight: 8.7 ± 0.8 kg), where 200,000 IU could be prescribed to infants with a similar body weight, 31% of the piglets were hypervitaminotic, the 25,000 IU group was 100% VA adequate, and the placebo group was 100% deficient. The MRDR test measured deficiency in 50% and 70% of the placebo group in each study but had 3 false positives among hypervitaminotic piglets in Study 1. CONCLUSIONS: Repeated high-dose VA may cause hypervitaminosis, indicating dose sizes may need reduction. The MRDR resulted in false positives in a hypervitaminotic state during malnutrition and should be paired with serum retinyl ester evaluation to enhance VA status assessment in populations with overlapping interventions.

10.
Wilderness Environ Med ; : 10806032241249126, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38710506

RESUMEN

The Wilderness Medical Society convened a panel to review available evidence supporting practices for medical direction of search and rescue teams. This panel included of members of the Wilderness Medical Society Search and Rescue Committee, the National Association of EMS Physicians Wilderness Committee, and leadership of the Mountain Rescue Association. Literature about definitions and terminology, epidemiology, currently accepted best practices, and regulatory and legal considerations was reviewed. The panel graded available evidence supporting practices according to the American College of Chest Physicians criteria and then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking.

11.
Clin Infect Dis ; 78(Supplement_2): S83-S92, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38662692

RESUMEN

Over the past decade, considerable progress has been made in the control, elimination, and eradication of neglected tropical diseases (NTDs). Despite these advances, most NTD programs have recently experienced important setbacks; for example, NTD interventions were some of the most frequently and severely impacted by service disruptions due to the coronavirus disease 2019 (COVID-19) pandemic. Mathematical modeling can help inform selection of interventions to meet the targets set out in the NTD road map 2021-2030, and such studies should prioritize questions that are relevant for decision-makers, especially those designing, implementing, and evaluating national and subnational programs. In September 2022, the World Health Organization hosted a stakeholder meeting to identify such priority modeling questions across a range of NTDs and to consider how modeling could inform local decision making. Here, we summarize the outputs of the meeting, highlight common themes in the questions being asked, and discuss how quantitative modeling can support programmatic decisions that may accelerate progress towards the 2030 targets.


Asunto(s)
COVID-19 , Enfermedades Desatendidas , Medicina Tropical , Enfermedades Desatendidas/prevención & control , Humanos , COVID-19/epidemiología , COVID-19/prevención & control , Modelos Teóricos , Organización Mundial de la Salud , SARS-CoV-2 , Toma de Decisiones , Salud Global
12.
PLoS Comput Biol ; 20(4): e1011993, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38557869

RESUMEN

The intensification of intervention activities against the fatal vector-borne disease gambiense human African trypanosomiasis (gHAT, sleeping sickness) in the last two decades has led to a large decline in the number of annually reported cases. However, while we move closer to achieving the ambitious target of elimination of transmission (EoT) to humans, pockets of infection remain, and it becomes increasingly important to quantitatively assess if different regions are on track for elimination, and where intervention efforts should be focused. We present a previously developed stochastic mathematical model for gHAT in the Democratic Republic of Congo (DRC) and show that this same formulation is able to capture the dynamics of gHAT observed at the health area level (approximately 10,000 people). This analysis was the first time any stochastic gHAT model has been fitted directly to case data and allows us to better quantify the uncertainty in our results. The analysis focuses on utilising a particle filter Markov chain Monte Carlo (MCMC) methodology to fit the model to the data from 16 health areas of Mosango health zone in Kwilu province as a case study. The spatial heterogeneity in cases is reflected in modelling results, where we predict that under the current intervention strategies, the health area of Kinzamba II, which has approximately one third of the health zone's cases, will have the latest expected year for EoT. We find that fitting the analogous deterministic version of the gHAT model using MCMC has substantially faster computation times than fitting the stochastic model using pMCMC, but produces virtually indistinguishable posterior parameterisation. This suggests that expanding health area fitting, to cover more of the DRC, should be done with deterministic fits for efficiency, but with stochastic projections used to capture both the parameter and stochastic variation in case reporting and elimination year estimations.


Asunto(s)
Tripanosomiasis Africana , Animales , Humanos , Tripanosomiasis Africana/epidemiología , República Democrática del Congo/epidemiología , Modelos Teóricos , Predicción , Cadenas de Markov , Trypanosoma brucei gambiense
14.
Nature ; 628(8007): 365-372, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38509364

RESUMEN

Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago1. Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements2. Here we report an archaeological site-Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago-that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow. The diet included a wide range of terrestrial and aquatic animals. Stable oxygen isotopes from fossil mammal teeth and ostrich eggshell show that the site was occupied during a period of high seasonal aridity. The unusual abundance of fish suggests that capture occurred in the ever smaller and shallower waterholes of a seasonal river during a long dry season, revealing flexible adaptations to challenging climatic conditions during the Middle Stone Age. Adaptive foraging along dry-season waterholes would have transformed seasonal rivers into 'blue highway' corridors, potentially facilitating an out-of-Africa dispersal and suggesting that the event was not restricted to times of humid climates. The behavioural flexibility required to survive seasonally arid conditions in general, and the apparent short-term effects of the Toba supereruption in particular were probably key to the most recent dispersal and subsequent worldwide expansion of modern humans.


Asunto(s)
Clima , Migración Humana , Animales , Humanos , Arqueología , Etiopía , Mamíferos , Estaciones del Año , Dieta/historia , Historia Antigua , Migración Humana/historia , Fósiles , Struthioniformes , Sequías , Peces
15.
J Med Chem ; 67(6): 5064-5074, 2024 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-38480493

RESUMEN

Protein-based 18F-PET tracers offer new possibilities in early disease detection and personalized medicine. Their development relies heavily on the availability and effectiveness of 18F-prosthetic groups. We prepared and evaluated a novel arginine-selective prosthetic group, 4-[18F]fluorophenylglyoxal ([18F]FPG). [18F]FPG was radiosynthesized by a one-pot, two-step procedure with a non-decay-corrected (n.d.c.) isolated radiochemical yield (RCY) of 41 ± 8% (n = 10). [18F]FPG constitutes a generic tool for 18F-labeling of various proteins, including human serum albumin (HSA), ubiquitin, interleukin-2, and interleukin-4 in ∼30-60% n.d.c. isolated RCYs. [18F]FPG conjugation with arginine residues is highly selective, even in the presence of a large excess of lysine, cysteine, and histidine. [18F]FPG protein conjugates are able to preserve the binding affinity of the native proteins while also demonstrating excellent in vivo stability. The [18F]FPG-HSA conjugate has prolonged blood retention, which can be applied as a potential blood pool PET imaging agent. Thus, [18F]FPG is an arginine-selective bioconjugation reagent that can be effectively used for the development of 18F-labeled protein radiopharmaceuticals.


Asunto(s)
Tomografía de Emisión de Positrones , Radiofármacos , Humanos , Tomografía de Emisión de Positrones/métodos , Radiofármacos/química , Radioquímica , Albúmina Sérica Humana , Ubiquitina , Radioisótopos de Flúor/química
16.
Wilderness Environ Med ; 35(1_suppl): 94S-111S, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38379489

RESUMEN

The Wilderness Medical Society convened a panel to review available evidence supporting practices for acute management of drowning in out-of-hospital and emergency care settings. Literature about definitions and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded available evidence supporting practices according to the American College of Chest Physicians criteria and then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking. This is the second update to the original practice guidelines published in 2016 and updated in 2019.


Asunto(s)
Ahogamiento , Medicina Silvestre , Humanos , Ahogamiento/prevención & control , Servicios Médicos de Urgencia , Resucitación , Sociedades Médicas
17.
Res Sq ; 2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38313253

RESUMEN

Sleep and circadian rhythm disruptions are comorbid features of many pathologies and can negatively influence numerous health conditions, including degenerative diseases, metabolic illnesses, cancer, and various neurological disorders. Genetic association studies linking sleep and circadian disturbances with disease susceptibility have mainly focused on changes in gene expression due to mutations, such as single-nucleotide polymorphisms. Thus, associations between sleep and/or circadian rhythm and alternative polyadenylation (APA), particularly in the context of other health challenges, are largely undescribed. APA is a process that generates various transcript isoforms from the same gene, resulting in effects on mRNA translation, stability, localization, and subsequent function. Here, we have identified unique APAs in rat brain that exhibit time-of-day-dependent oscillations in expression as well as APAs that are altered by sleep deprivation and the subsequent recovery period. Genes affected by APA usage include Mapt/Tau, Ntrk2, Homer1A, Sin3band Sorl. Sorl1 has two APAs which cycle with a 24 h period, one additional APA cycles with a 12 h period and one more that is reduced during recovery sleep. Finally, we compared sleep- or circadian-associated APAs with recently described APA-linked brain disorder susceptibility genes and found 46 genes in common.

18.
Res Sq ; 2024 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-38260456

RESUMEN

Telomeres undergo shortening with each cell division, serving as biomarkers of human aging, which is characterized by short telomeres and restricted telomerase expression in adult tissues. Contrarily, mice, featuring their longer telomeres and widespread telomerase activity, present limitations as models for understanding telomere-related human biology and diseases. To bridge this gap, we engineered a mouse strain with a humanized mTert gene, hmTert, wherein specific non-coding sequences were replaced with their human counterparts. The hmTert gene, encoding the wildtype mTert protein, was repressed in adult tissues beyond the gonads and thymus, closely resembling the regulatory pattern of the human TERT gene. Remarkably, the hmTert gene rescued telomere dysfunction in late generations of mTert-knockout mice. Through successive intercrosses of Terth/- mice, telomere length progressively declined, stabilizing below 10-kb. Terth/h mice achieved a human-like average telomere length of 10-12 kb, contrasting with the 50-kb length in wildtype C57BL/6J mice. Despite shortened telomeres, Terth/h mice maintained normal body weight and cell homeostasis in highly proliferative tissues. Notably, colonocyte proliferation decreased significantly in Terth/h mice during dextran sodium sulfate-induced ulcerative colitis-like pathology, suggesting limitations on cellular renewal due to short telomeres. Our findings underscore the genetic determination of telomere homeostasis in mice by the Tert gene. These mice, exhibiting humanized telomere homeostasis, serve as a valuable model for exploring fundamental questions related to human aging and cancer.

19.
J Pers ; 92(2): 421-435, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36938751

RESUMEN

OBJECTIVE: Individuals with a tendency to conceal unflattering information about themselves are more likely to be preoccupied by their secrets and tend to report more negative affect. According to theory, this negative affect is due to self-concealers' conflicting motivation to be authentic in their relationship but fear the negative consequences should they reveal their secrets, which promotes ill-fated attempts to suppress. The purpose of the current study was to test a central component of this model. METHODS: Two studies of adults who were in a romantic relationship and keeping a secret from their partner (combined N = 635; 67.2% women; Mage  = 39.6, SD = 11.9) were surveyed on four biweekly occasions. Multilevel mediation analyses were conducted to test whether preoccupation and suppression mediated the link between self-concealing and negative affect and guilt. RESULTS: The data support the hypotheses. Self-concealers were more preoccupied with and prone to suppress their secret than those low on the trait, which, in turn, predicted greater negative affect and guilt. CONCLUSION: The findings suggest that self-concealers' insecurities and fear of the relational consequences of disclosure set the stage for the debilitating cycle of suppression and preoccupation that leaves them feeling anxious and guilty.


Asunto(s)
Emociones , Culpa , Adulto , Humanos , Femenino , Masculino , Confidencialidad , Ansiedad , Encuestas y Cuestionarios
20.
Emerg Microbes Infect ; 13(1): 2290834, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38047354

RESUMEN

The spread of Lassa virus (LASV) in Guinea, Liberia and Sierra Leone, which together are named the Mano River Union (MRU) area, was examined phylogeographically. To provide a reliable evolutionary scenario, new rodent-derived, whole LASV sequences were included. These were generated by metatranscriptomic next-generation sequencing from rodents sampled between 2003 and 2020 in 21 localities of Guinea and Sierra Leone. An analysis was performed using BEAST to perform continuous phylogeographic inference and EvoLaps v36 to visualize spatio-temporal spread. LASV was identified as expected in its primary host reservoir, the Natal multimammate mouse (Mastomys natalensis), and also in two Guinean multimammate mice (Mastomys erythroleucus) in northern Sierra Leone and two rusty-bellied brush-furred mice (Lophuromys sikapusi) in southern Sierra Leone. This finding is consistent with the latter two species being secondary host reservoirs. The strains in these three species were very closely related in LASV lineage IV. Phylogenetic analysis indicated that the most recent common ancestor of lineage IV existed 316-374 years ago and revealed distinct, well-supported clades from Sierra Leone (Bo, Kabala and Kenema), Guinea (Faranah, Kissidougou-Guekedou and Macenta) and Liberia (Phebe-Ganta). The phylogeographic scenario suggests southern Guinea as the point of origin of LASV in the MRU area, with subsequent spread to towards Mali, Liberia and Sierra Leone at a mean speed of 1.6 to 1.1 km/year.


Asunto(s)
Fiebre de Lassa , Virus Lassa , Ratones , Animales , Virus Lassa/genética , Fiebre de Lassa/epidemiología , Filogenia , África Occidental/epidemiología , Murinae
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