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1.
J Infect Dis ; 229(1): 4-6, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38000901

RESUMO

Bangladesh is currently experiencing the country's largest and deadliest dengue outbreak on record. This year's outbreak has been characterized by an early seasonal surge in cases, rapid geographic spread, and a high fatality rate. The alarming trends in dengue incidence and mortality this year is an urgent wake-up call for public health policymakers and researchers to pay closer attention to dengue dynamics in South Asia, to strengthen the surveillance system and diagnostic capabilities, and to develop tools and methods for guiding strategic resource allocation and control efforts.


Assuntos
Dengue , Humanos , Dengue/epidemiologia , Dengue/diagnóstico , Bangladesh/epidemiologia , Incidência , Surtos de Doenças , Saúde Pública
2.
PLoS Biol ; 18(10): e3000878, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33091022

RESUMO

Predicting how pathogen populations will change over time is challenging. Such has been the case with Streptococcus pneumoniae, an important human pathogen, and the pneumococcal conjugate vaccines (PCVs), which target only a fraction of the strains in the population. Here, we use the frequencies of accessory genes to predict changes in the pneumococcal population after vaccination, hypothesizing that these frequencies reflect negative frequency-dependent selection (NFDS) on the gene products. We find that the standardized predicted fitness of a strain, estimated by an NFDS-based model at the time the vaccine is introduced, enables us to predict whether the strain increases or decreases in prevalence following vaccination. Further, we are able to forecast the equilibrium post-vaccine population composition and assess the invasion capacity of emerging lineages. Overall, we provide a method for predicting the impact of an intervention on pneumococcal populations with potential application to other bacterial pathogens in which NFDS is a driving force.


Assuntos
Evolução Molecular Direcionada , Streptococcus pneumoniae/fisiologia , Simulação por Computador , Modelos Biológicos , Vacinas Pneumocócicas/imunologia , Streptococcus pneumoniae/imunologia
3.
Molecules ; 28(17)2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37687058

RESUMO

Breast cancer, due to its high incidence and mortality, is a public health problem worldwide. Current chemotherapy uses non-specific cytotoxic drugs, which inhibit tumor growth but cause significant adverse effects. (-)-Epicatechin (EC) is part of a large family of biomolecules called flavonoids. It is widely distributed in the plant kingdom; it can be found in green tea, grapes, and cocoa. Several studies in animals and humans have shown that EC induces beneficial effects in the skeletal muscle and the cardiovascular system, reducing risk factors such as arterial hypertension, endothelial dysfunction, damage to skeletal muscle structure, and mitochondrial malfunction by promoting mitochondrial biogenesis, with no adverse effects reported. Recently, we reported that EC had an antitumor effect in a murine triple-negative mammary gland tumor model, decreasing tumoral size and volume and increasing survival by 44%. This work aimed to characterize the effects of flavanol EC on proliferation, migration, and metastasis markers of triple-negative murine breast (4T1) cancer cells in culture. We found proliferation diminished and Bax/Bcl2 ratio increased. When the migration of culture cells was evaluated, we observed a significant reduction in migration. Also, the relative expression of the genes associated with metastasis, Cdh1, Mtss1, Pten, Bmrs, Fat1, and Smad4, was increased. In conclusion, these results contribute to understanding molecular mechanisms activated by EC that can inhibit metastatic-associated proliferation, migration, and invasion of murine breast cancer cells.


Assuntos
Catequina , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Humanos , Animais , Camundongos , Catequina/farmacologia , Processos Neoplásicos , Flavonoides/farmacologia , Proliferação de Células
4.
Urban Rev ; : 1-29, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37363290

RESUMO

Research on Culturally Responsive Education (CRE) to date has mostly focused on identifying the aspects of education that already work for Black, Indigenous, and Students of Color. Building on this important literature base, this qualitative study examines the implementation, rather than the identification, of CRE practices. The seven New York City public schools that participated in the study were making school-wide changes for CRE as part of a program for Competency-Based Education (CBE) for personalizing learning for students. Both CRE and CBE are employed in schools to address common issues associated with educational inequities such as irrelevant lessons, teacher biases, one-size-fits-all instruction, and systemic racism. Based on interviews with teachers at the study schools, our findings demonstrated that teachers translated CRE theory into their CBE practice in three key ways: (1) deficit practices, where instructional choices were treated as neutral; (2) access practices, where instruction was differentiated but was not culturally responsive; and (3) transformative practices, where student agency challenged traditional structures. We argue that for schools and educators to meaningfully grapple with the issues of power they seek to address by engaging in CRE, they must embrace and nurture a more radical CRE imagination that leads to deeper school transformation.

5.
J Infect Dis ; 224(6): 976-982, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34191025

RESUMO

BACKGROUND: Serial screening is critical for restricting spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by facilitating timely identification of infected individuals to interrupt transmission. Variation in sensitivity of different diagnostic tests at different stages of infection has not been well documented. METHODS: In a longitudinal study of 43 adults newly infected with SARS-CoV-2, all provided daily saliva and nasal swabs for quantitative reverse transcription polymerase chain reaction (RT-qPCR), Quidel SARS Sofia antigen fluorescent immunoassay (FIA), and live virus culture. RESULTS: Both RT-qPCR and Quidel SARS Sofia antigen FIA peaked in sensitivity during the period in which live virus was detected in nasal swabs, but sensitivity of RT-qPCR tests rose more rapidly prior to this period. We also found that serial testing multiple times per week increases the sensitivity of antigen tests. CONCLUSIONS: RT-qPCR tests are more effective than antigen tests at identifying infected individuals prior to or early during the infectious period and thus for minimizing forward transmission (given timely results reporting). All tests showed >98% sensitivity for identifying infected individuals if used at least every 3 days. Daily screening using antigen tests can achieve approximately 90% sensitivity for identifying infected individuals while they are viral culture positive.


Assuntos
Teste para COVID-19 , COVID-19/diagnóstico , Testes Diagnósticos de Rotina , SARS-CoV-2/isolamento & purificação , Adulto , Idoso , Animais , Antígenos Virais/análise , Chlorocebus aethiops , Feminino , Humanos , Estudos Longitudinais , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Saliva , Sensibilidade e Especificidade , Células Vero , Adulto Jovem
7.
J Infect Dis ; 221(2): 238-242, 2020 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-31776559

RESUMO

Rotavirus, a diarrheal pathogen spread via fecal-oral transmission, is typically characterized by a winter incidence peak in most countries. Unlike for cholera and other waterborne infections, the role of sanitation and socioeconomic factors on the spatial variation of rotavirus seasonality remains unclear. In the current study, we analyzed their association with rotavirus seasonality, specifically the odds of monsoon cases, across 46 locations from 2001 to 2012 in Dhaka. Drinking water from tube wells, compared to other sources, has a clear protective effect against cases during the monsoon, when flooding and water contamination are more likely. This finding supports a significant environmental component of transmission.


Assuntos
Água Potável/análise , Infecções por Rotavirus/transmissão , Poços de Água , Bangladesh/epidemiologia , Estudos Transversais , Humanos , Rotavirus/isolamento & purificação , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/prevenção & controle , Estações do Ano , População Urbana
8.
Int J Exp Pathol ; 101(1-2): 55-64, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32459025

RESUMO

Rheumatoid arthritis is a disabling autoimmune disease with a high global prevalence. Treatment with disease-modifying anti-arthritic drugs (DIMARDs) has been routinely used with beneficial effects but with adverse long-term consequences; novel targeted biologics and small-molecule inhibitors are promising options. In this study, we investigated whether purified omega unsaturated fatty acids (ω-UFAs) and dialysable leukocyte extracts (DLEs) prevented the development of arthritis in a model of collagen-induced arthritis (CIA) in mice. We also investigated whether the transcription factor NF-κB and the NLRP3 inflammasome were involved in the process and whether their activity was modulated by treatment. The development of arthritis was evaluated for 84 days following treatment with nothing, dexamethasone, DLEs, docosahexaenoic acid, arachidonic acid, and oleic acid. Progression of CIA was monitored by evaluating clinical manifestations, inflammatory changes, and histological alterations in the pads' articular tissues. Both DLEs and ω-UFAs led to an almost complete inhibition of the inflammatory histopathology of CIA and this was concomitant with the inhibition of NF-kB and the inhibition of the activation of NLRP3. These data suggest that ω-UFAs and DLEs might have NF-κB as a common target and that they might be used as ancillary medicines in the treatment of arthritis.


Assuntos
Anti-Inflamatórios/farmacologia , Antirreumáticos/farmacologia , Artrite Experimental/prevenção & controle , Cartilagem Articular/efeitos dos fármacos , Extratos Celulares/farmacologia , Ácidos Graxos Insaturados/farmacologia , Leucócitos , Animais , Ácido Araquidônico/farmacologia , Artrite Experimental/induzido quimicamente , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Cartilagem Articular/metabolismo , Cartilagem Articular/patologia , Colágeno Tipo II , Diálise , Ácidos Docosa-Hexaenoicos/farmacologia , Feminino , Inflamassomos/efeitos dos fármacos , Inflamassomos/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos DBA , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Ácido Oleico/farmacologia
9.
Proc Natl Acad Sci U S A ; 113(15): 4092-7, 2016 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-27035949

RESUMO

The role of climate forcing in the population dynamics of infectious diseases has typically been revealed via retrospective analyses of incidence records aggregated across space and, in particular, over whole cities. Here, we focus on the transmission dynamics of rotavirus, the main diarrheal disease in infants and young children, within the megacity of Dhaka, Bangladesh. We identify two zones, the densely urbanized core and the more rural periphery, that respond differentially to flooding. Moreover, disease seasonality differs substantially between these regions, spanning variation comparable to the variation from tropical to temperate regions. By combining process-based models with an extensive disease surveillance record, we show that the response to climate forcing is mainly seasonal in the core, where a more endemic transmission resulting from an asymptomatic reservoir facilitates the response to the monsoons. The force of infection in this monsoon peak can be an order of magnitude larger than the force of infection in the more epidemic periphery, which exhibits little or no postmonsoon outbreak in a pattern typical of nearby rural areas. A typically smaller peak during the monsoon season nevertheless shows sensitivity to interannual variability in flooding. High human density in the core is one explanation for enhanced transmission during troughs and an associated seasonal monsoon response in this diarrheal disease, which unlike cholera, has not been widely viewed as climate-sensitive. Spatial demographic, socioeconomic, and environmental heterogeneity can create reservoirs of infection and enhance the sensitivity of disease systems to climate forcing, especially in the populated cities of the developing world.


Assuntos
Clima , Países em Desenvolvimento , Diarreia/epidemiologia , Infecções por Rotavirus/epidemiologia , Bangladesh/epidemiologia , Inundações , Humanos , Estações do Ano
10.
AAPS PharmSciTech ; 19(8): 3355-3361, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29948979

RESUMO

Additive manufacturing (3D printing) permits the fabrication of tablets in shapes unattainable by powder compaction, and so the effects of geometry on drug release behavior is easily assessed. Here, tablets (printlets) comprising of paracetamol dispersed in polyethylene glycol were printed using stereolithographic 3D printing. A number of geometric shapes were produced (cube, disc, pyramid, sphere and torus) with either constant surface area (SA) or constant surface area/volume ratio (SA/V). Dissolution testing showed that printlets with constant SA/V ratio released drug at the same rate, while those with constant SA released drug at different rates. A series of tori with increasing SA/V ratio (from 0.5 to 2.4) were printed, and it was found that dissolution rate increased as the SA/V ratio increased. The data show that printlets can be fabricated in multiple shapes and that dissolution performance can be maintained if the SA/V ratio is constant or that dissolution performance of printlets can be fine-tuned by varying SA/V ratio. The results suggest that 3D printing is therefore a suitable manufacturing method for personalized dosage forms.


Assuntos
Liberação Controlada de Fármacos , Estereolitografia , Comprimidos/química , Tecnologia Farmacêutica/métodos , Acetaminofen/química , Polietilenoglicóis/química , Pós , Impressão Tridimensional
11.
Cir Cir ; 92(5): 679-682, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39401780

RESUMO

INTRODUCTION: Gastrointestinal stromal tumors (GIST) are rare, reported incidence is between 10 to 15 cases per million of habitants. They are usually located in the stomach (56%), small intestine (32%), colon-rectum (6%), and esophagus (<1%). Its symptoms include nausea, vomiting and abdominal fullness; 30% are asymptomatic. Incidental finding during abdominal surgery or imaging studies is common. Resection with negative margins is the standard treatment. CASE REPORT: A 69-year-old female patient who debuted with massive digestive tract bleeding, requiring surgical treatment. A tumor was detected at jejunum compatible with a GIST.


INTRODUCCIÓN: Los tumores del estroma gastrointestinal (GIST) son poco frecuentes, con una incidencia de 10 a 15 casos por millón de habitantes. Suelen localizarse en el estómago (56%), el intestino delgado (32%), el colon-recto (6%) y el esófago (< 1%). Sus síntomas incluyen náusea, vómito y plenitud abdominal; el 30% son asintomáticos. Es común su hallazgo incidental durante una cirugía abdominal o en estudios de imagen. La resección con márgenes negativos es el tratamiento estándar. CASO CLÍNICO: Mujer de 69 años que debuta con hemorragia masiva de tubo digestivo, requiriendo tratamiento quirúrgico. Se detecta un tumor de yeyuno compatible con GIST.


Assuntos
Hemorragia Gastrointestinal , Tumores do Estroma Gastrointestinal , Neoplasias do Jejuno , Humanos , Tumores do Estroma Gastrointestinal/complicações , Tumores do Estroma Gastrointestinal/cirurgia , Feminino , Idoso , Hemorragia Gastrointestinal/etiologia , Neoplasias do Jejuno/complicações , Neoplasias do Jejuno/cirurgia , Achados Incidentais
12.
PNAS Nexus ; 2(9): pgad307, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38741656

RESUMO

Although the drivers of influenza have been well studied in high-income settings in temperate regions, many open questions remain about the burden, seasonality, and drivers of influenza dynamics in the tropics. In temperate climates, the inverse relationship between specific humidity and transmission can explain much of the observed temporal and spatial patterns of influenza outbreaks. Yet, this relationship fails to explain seasonality, or lack there-of, in tropical and subtropical countries. Here, we analyzed eight years of influenza surveillance data from 12 locations in Bangladesh to quantify the role of climate in driving disease dynamics in a tropical setting with a distinct rainy season. We find strong evidence for a nonlinear bimodal relationship between specific humidity and influenza transmission in Bangladesh, with highest transmission occurring for relatively low and high specific humidity values. We simulated influenza burden under current and future climate in Bangladesh using a mathematical model with a bimodal relationship between humidity and transmission, and decreased transmission at very high temperatures, while accounting for changes in population immunity. The climate-driven mechanistic model can accurately capture both the temporal and spatial variation in influenza activity observed across Bangladesh, highlighting the usefulness of mechanistic models for low-income countries with inadequate surveillance. By using climate model projections, we also highlight the potential impact of climate change on influenza dynamics in the tropics and the public health consequences.

13.
Adv Drug Deliv Rev ; 198: 114859, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37149039

RESUMO

Modern pharmaceutical interventions are shifting from traditional "one-size-fits-all" approaches toward tailored therapies. Following the regulatory approval of Spritam®, the first marketed drug manufactured using three-dimensional printing (3DP) technologies, there is a precedence set for the use of 3DP in the manufacture of pharmaceutical products. The involvement of 3DP technologies in pharmaceutical research has demonstrated its capabilities in enabling the customisation of characteristics such as drug dosing, release characteristics and product designs on an individualised basis. Nonetheless, research into 3DP implantable drug delivery devices lags behind that for oral devices, cell-based therapies and tissue engineering applications. The recent efforts and initiatives to address the disparity in women's health is overdue but should provide a drive for more research into this area, especially using new and emerging technologies as 3DP. Therefore, the focus of this review has been placed on the unique opportunity of formulating personalised implantable drug delivery systems using 3DP for women's health applications, particularly passive implants. An evaluation of the current landscape and key formulation challenges for achieving this is provided supplemented with critical insight into the current global regulatory status and its outlook.


Assuntos
Sistemas de Liberação de Medicamentos , Farmácia , Feminino , Humanos , Sistemas de Liberação de Medicamentos/métodos , Impressão Tridimensional , Preparações Farmacêuticas , Medicina de Precisão/métodos , Tecnologia Farmacêutica/métodos
14.
Sci Adv ; 9(31): eadh9920, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37531439

RESUMO

SARS-CoV-2 vaccines have been distributed at unprecedented speed. Still, little is known about temporal vaccination trends, their association with socioeconomic inequality, and their consequences for disease control. Using data from 161 countries/territories and 58 states, we examined vaccination rates across high and low socioeconomic status (SES), showing that disparities in coverage exist at national and subnational levels. We also identified two distinct vaccination trends: a rapid initial rollout, quickly reaching a plateau, or sigmoidal and slow to begin. Informed by these patterns, we implemented an SES-stratified mechanistic model, finding profound differences in mortality and incidence across these two vaccination types. Timing of initial rollout affects disease outcomes more substantially than final coverage or degree of SES disparity. Unexpectedly, timing is not associated with wealth inequality or GDP per capita. While socioeconomic disparity should be addressed, accelerating initial rollout for all over focusing on increasing coverage is an accessible intervention that could minimize the burden of disease across socioeconomic groups.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Vacinas contra COVID-19 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Vacinação , Disparidades Socioeconômicas em Saúde
15.
Artigo em Inglês | MEDLINE | ID: mdl-38051475

RESUMO

The leading cause of death worldwide and a significant factor in decreased quality of life are the cardiovascular diseases. Endovascular operations like angioplasty, stent placement, or atherectomy are often used in vascular surgery to either dilate a narrowed blood artery or remove a blockage. As an alternative, a vascular transplant may be utilised to replace or bypass a dysfunctional or blocked blood vessel. Despite the advancements in endovascular surgery and its popularisation over the past few decades, vascular bypass grafting remains prevalent and is considered the best option for patients in need of long-term revascularisation treatments. Consequently, the demand for synthetic vascular grafts composed of biocompatible materials persists. To address this need, biodegradable clopidogrel (CLOP)-loaded vascular grafts have been fabricated using the digital light processing (DLP) 3D printing technique. A mixture of polylactic acid-polyurethane acrylate (PLA-PUA), low molecular weight polycaprolactone (L-PCL), and CLOP was used to achieve the required mechanical and biological properties for vascular grafts. The 3D printing technology provides precise detail in terms of shape and size, which lead to the fabrication of customised vascular grafts. The fabricated vascular grafts were fully characterised using different techniques, and finally, the drug release was evaluated. Results suggested that the performed 3D-printed small-diameter vascular grafts containing the highest CLOP cargo (20% w/w) were able to provide a sustained drug release for up to 27 days. Furthermore, all the CLOP-loaded 3D-printed materials resulted in a substantial reduction of the platelet deposition across their surface compared to the blank materials containing no drug. Haemolysis percentage for all the 3D-printed samples was lower than 5%. Moreover, 3D-printed materials were able to provide a supportive environment for cellular attachment, viability, and growth. A substantial increase in cell growth was detected between the blank and drug-loaded grafts.

16.
Rev Chilena Infectol ; 29(2): 169-74, 2012 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-22689032

RESUMO

INTRODUCTION: Respiratory viruses are the leading cause of acute respiratory tract infection (ARI) in children. It has been reported that viral respiratory co-infection could be associated with severe clinical course. OBJECTIVES: To describe the frequency of viral co-infection in children admitted for AlRI and evaluate whether this co-infection was associated with more severe clinical course. PATIENTS AND METHODS: Prospective, descriptive study in pediatric patients who were hospitalized for ARI, with molecular detection of at least 1 respiratory virus in nasopharyngeal sample studied by PCR-Microarray for 17 respiratory viruses. RESULTS: 110 out of 147 patients with detection of > 1 respiratory virus were included. Viral co-infection was detected in 41/110 (37%). 22/110 children (20%) were classified as moderate to severe clinical course and 88/110 (80%) were classified as mild clinical course. In the group of moderate to severe clinical course, viral respiratory co-infection was detected in 6/22 (27.3%), compared to 35/88 (39.8 %) in the mild clinical course group. No statistically significant difference was found regarding the presence of co-infection between groups (p = 0.33). CONCLUSIONS: We detected high rates of viral co-infection in children with ARI. It was not possible to demonstrate that viral co-infections were related with severe clinical course in hospitalized children.


Assuntos
Coinfecção/virologia , Nasofaringe/virologia , Infecções Respiratórias/virologia , Viroses/virologia , Doença Aguda , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Estudos Prospectivos , Índice de Gravidade de Doença
17.
Front Digit Health ; 4: 814226, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36588749

RESUMO

Active gaming is a form of video gaming that requires full body motion or varying degrees of physical activity to play a game. While active gaming has regained momentum, the design and specific components of active games that make them engaging are limited. This study identifies, analyzes, and categorizes specific design mechanics and features used in active games. It answers the question: Which, if any, game mechanics and features can a panel of experts in the academic, health, and game industry agree on as valuable and impactful to the construction of successful and engaging active games? Using a Delphi study, nine experts answered questions related to active gaming. They reached an agreement on 20 of the 21 inquiries regarding game design focused on motivation, social influence, and flow. Their feedback offers recommendations on the design of future active games and identifies emerging trends. This study shares their notes and translates the findings into specific recommendations for developers on the design of active games. The field of active gaming has matured; there are pockets of experts in design, research, and implementation. Active gaming has maintained continuity; however, player enthusiasm and engagement in these types of games are consistently an issue. Through better game design and newer types of active games, players' interest will persist. These guidelines can inform developers working with newer technologies, such as mobile devices, enhanced game consoles, and virtual and augmented reality platforms, to create active games that inspire gamers to play.

18.
Open Forum Infect Dis ; 9(7): ofac192, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35791353

RESUMO

Background: The global effort to vaccinate people against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during an ongoing pandemic has raised questions about how vaccine breakthrough infections compare with infections in immunologically naive individuals and the potential for vaccinated individuals to transmit the virus. Methods: We examined viral dynamics and infectious virus shedding through daily longitudinal sampling in 23 adults infected with SARS-CoV-2 at varying stages of vaccination, including 6 fully vaccinated individuals. Results: The durations of both infectious virus shedding and symptoms were significantly reduced in vaccinated individuals compared with unvaccinated individuals. We also observed that breakthrough infections are associated with strong tissue compartmentalization and are only detectable in saliva in some cases. Conclusions: Vaccination shortens the duration of time of high transmission potential, minimizes symptom duration, and may restrict tissue dissemination.

19.
Nat Microbiol ; 7(5): 640-652, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35484231

RESUMO

The dynamics of SARS-CoV-2 replication and shedding in humans remain poorly understood. We captured the dynamics of infectious virus and viral RNA shedding during acute infection through daily longitudinal sampling of 60 individuals for up to 14 days. By fitting mechanistic models, we directly estimated viral expansion and clearance rates and overall infectiousness for each individual. Significant person-to-person variation in infectious virus shedding suggests that individual-level heterogeneity in viral dynamics contributes to 'superspreading'. Viral genome loads often peaked days earlier in saliva than in nasal swabs, indicating strong tissue compartmentalization and suggesting that saliva may serve as a superior sampling site for early detection of infection. Viral loads and clearance kinetics of Alpha (B.1.1.7) and previously circulating non-variant-of-concern viruses were mostly indistinguishable, indicating that the enhanced transmissibility of this variant cannot be explained simply by higher viral loads or delayed clearance. These results provide a high-resolution portrait of SARS-CoV-2 infection dynamics and implicate individual-level heterogeneity in infectiousness in superspreading.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Carga Viral , Eliminação de Partículas Virais
20.
Nat Commun ; 12(1): 1555, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33692343

RESUMO

A counterargument to the importance of climate change for malaria transmission has been that regions where an effect of warmer temperatures is expected, have experienced a marked decrease in seasonal epidemic size since the turn of the new century. This decline has been observed in the densely populated highlands of East Africa at the center of the earlier debate on causes of the pronounced increase in epidemic size from the 1970s to the 1990s. The turnaround of the incidence trend around 2000 is documented here with an extensive temporal record for malaria cases for both Plasmodium falciparum and Plasmodium vivax in an Ethiopian highland. With statistical analyses and a process-based transmission model, we show that this decline was driven by the transient slowdown in global warming and associated changes in climate variability, especially ENSO. Decadal changes in temperature and concurrent climate variability facilitated rather than opposed the effect of interventions.


Assuntos
Malária/epidemiologia , África Oriental/epidemiologia , Aquecimento Global , Humanos , Incidência , Malária Falciparum/epidemiologia , Plasmodium falciparum/patogenicidade , Plasmodium vivax/patogenicidade , Temperatura
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