Publications by authors named "Kevin Merkel"

Article Synopsis
  • - Bombali virus (BOMV) is a new type of ebolavirus found in free-tailed bats across several African countries including Sierra Leone, Guinea, Kenya, and Mozambique.
  • - Researchers screened bat lungs and blood samples from Côte d'Ivoire and Tanzania but only found BOMV RNA in one bat from Tanzania, which is the first time ebolavirus has been detected in that country.
  • - This discovery extends the known distribution of BOMV and confirms that these bats can serve as natural hosts for the virus.
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Measles is a highly contagious airborne viral disease. It can lead to serious complications and death and is preventable by vaccination. The live-attenuated measles vaccine (LAMV) derived from a measles virus (MV) isolated in 1954 has been in use globally for six decades and protects effectively by providing a durable humoral and cell-mediated immunity.

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Advances in viral discovery techniques have led to the identification of numerous novel viruses in human samples. However, the low prevalence of certain viruses in humans raises doubts about their association with our species. To ascertain the authenticity of a virus as a genuine human-infecting agent, it can be useful to investigate the diversification of its lineage within hominines, the group encompassing humans and African great apes.

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  • HSV-2 is a common DNA virus with two main lineages: one in West and Central Africa and another present globally.
  • Competing theories exist about its migration out of Africa, either following early human migrations 50-100,000 years ago or spreading through the trans-Atlantic slave trade 150-500 years ago.
  • Analysis of newly sequenced HSV-2 genomes indicates that the virus likely originated in East Africa and spread globally about 22-29,000 years ago, coinciding with human migrations after the Last Glacial Maximum.
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The 1918 influenza pandemic was the deadliest respiratory pandemic of the 20th century and determined the genomic make-up of subsequent human influenza A viruses (IAV). Here, we analyze both the first 1918 IAV genomes from Europe and the first from samples prior to the autumn peak. 1918 IAV genomic diversity is consistent with a combination of local transmission and long-distance dispersal events.

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Background: Massive transfusions are associated with a high mortality rate, but there is little evidence indicating when such efforts are futile. The purpose of this study was to identify clinical variables that could be used as futility indicators in massively transfused patients.

Methods: We retrospectively analyzed 138 adult surgical patients at our institution receiving a massive transfusion (2016-2019).

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Viruses closely related to human pathogens can reveal the origins of human infectious diseases. Human herpes simplexvirus type 1 (HSV-1) and type 2 (HSV-2) are hypothesized to have arisen via host-virus codivergence and cross-species transmission. We report the discovery of novel herpes simplexviruses during a large-scale screening of fecal samples from wild gorillas, bonobos, and chimpanzees.

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Objective: To assess the ratio of non-red blood cell to red blood cell components required to avoid coagulopathy when transfusing large amounts of salvaged blood using laboratory test-guided therapy.

Design: Retrospective cohort study.

Setting: Single-center, academic hospital.

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Background: Over the past decade, patient blood management (PBM) programs have been developed to reduce allogeneic blood utilization. This is particularly important in pancreatic surgery, which has historically been associated with high transfusion requirements and morbid event rates. This study investigated blood utilization and clinical outcomes in pancreatic surgery before, during, and after the implementation of PBM.

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Background: The objective of this study was to determine if anesthesia providers can accurately estimate the cost of commonly used medications, supplies, and blood products.

Methods: This study was conducted between April and June 2019 at an academic tertiary care hospital. Anesthesia providers (certified registered nurse anesthetists [CRNAs], residents, and fellows/attendings) were surveyed on their knowledge of the cost of commonly used therapies.

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Background: Transvenous lead extractions (TLEs) have increased in number due to an increased prevalence of cardiac implantable devices. Bleeding complications associated with TLEs can be catastrophic, and many institutions order blood components to be available in the procedure room. There are few studies supporting or refuting this practice.

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Many infectious diseases are thought to have emerged in humans after the Neolithic revolution. Although it is broadly accepted that this also applies to measles, the exact date of emergence for this disease is controversial. We sequenced the genome of a 1912 measles virus and used selection-aware molecular clock modeling to determine the divergence date of measles virus and rinderpest virus.

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Yaws-like lesions are widely reported in wild African great apes, yet the causative agent has not been confirmed in affected animals. We describe yaws-like lesions in a wild chimpanzee in Guinea for which we demonstrate infection with Treponema pallidum subsp. pertenue.

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Background: Patients requiring extracorporeal membrane oxygenation (ECMO) support are critically ill and have substantial transfusion requirements, which convey both risks and benefits. A retrospective analysis was conducted to assess the association between blood component administration and adverse outcomes in adult, pediatric, and neonatal ECMO patients.

Methods: We evaluated 217 ECMO patients at a single center hospitalized between January 2009 and June 2016.

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Objective: Blood transfusions are given to approximately one-fifth of patients undergoing elective lumbar spine surgery, and previous studies have shown that transfusions are accompanied by increased complications and additional costs. One method for decreasing transfusions is administration of tranexamic acid (TXA). The authors sought to evaluate whether the cost of TXA is offset by the decrease in blood utilization in lumbar spine surgery patients.

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Background: Patient blood management (PBM) is especially applicable in major spine surgery, during which bleeding and transfusion are common. What remains unclear in this setting is the overall impact of bundled PBM measures on transfusion requirements and clinical outcomes. We compared these outcomes before and after implementing a PBM program.

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Article Synopsis
  • Stress plays a significant role in triggering neuropsychiatric disorders and relapse in addiction, suggesting that targeting the stress response may help treat substance use disorders with medications like anxiolytics.
  • The research highlights that α-adrenergic receptors (α-ARs) in the brain, particularly in the extended amygdala, are important for modulating stress responses, and these receptors function similarly even in non-noradrenergic areas.
  • The study found that guanfacine, an α2A-AR agonist, enhances neuronal activity in the dorsal bed nucleus of the stria terminalis (dBNST) and has the potential to manage craving and anxiety, although its impact on relapse remains unclear due to competing brain actions.
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Wildlife detection in urban areas is very challenging. Conventional monitoring techniques such as direct observation are faced with the limitation that urban wildlife is extremely elusive. It was recently shown that invertebrate-derived DNA (iDNA) can be used to assess wildlife diversity in tropical rainforests.

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Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities.

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Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) are seen as close relatives but also unambiguously considered as evolutionary independent units. Here, we sequenced the genomes of 18 HSV-2 isolates characterized by divergent UL30 gene sequences to further elucidate the evolutionary history of this virus. Surprisingly, genome-wide recombination analyses showed that all HSV-2 genomes sequenced to date contain HSV-1 fragments.

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Monitoring wildlife infectious agents requires acquiring samples suitable for analyses, which is often logistically demanding. A possible alternative to invasive or non-invasive sampling of wild-living vertebrates is the use of vertebrate material contained in invertebrates feeding on them, their feces, or their remains. Carrion flies have been shown to contain vertebrate DNA; here we investigate whether they might also be suitable for wildlife pathogen detection.

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Fecal samples are an important source of information on parasites (viruses, prokaryotes, or eukaryotes) infecting wild great apes. Molecular analysis of fecal samples has already been used for deciphering the origins of major human pathogens such as HIV-1 or Plasmodium falciparum. However, for apes that hunt (chimpanzees and bonobos), detection of parasite nucleic acids may reflect either true infection of the host of interest or ingestion of an infected prey, for example, another non-human primate.

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The severe Ebola virus disease epidemic occurring in West Africa stems from a single zoonotic transmission event to a 2-year-old boy in Meliandou, Guinea. We investigated the zoonotic origins of the epidemic using wildlife surveys, interviews, and molecular analyses of bat and environmental samples. We found no evidence for a concurrent outbreak in larger wildlife.

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DNA analysis from carrion flies (iDNA analysis) has recently been promoted as a powerful tool for cost- and time-efficient monitoring of wildlife. While originally applied to identify any mammalian species present in an area, it should also allow for targeted detection of species and individuals. Using carrion flies captured in the Taï National Park, Côte d'Ivoire, we assessed this possibility by (i) screening carrion fly DNA extracts with nonspecific and species-specific PCR systems, respectively, targeting mitochondrial DNA (mtDNA) fragments of any mammal or of Jentink's duiker (Cephalophus jentinki), three colobine monkeys (subfamily Colobinae) and sooty mangabey (Cercocebus atys); and (ii) genotyping carrion fly extracts containing sooty mangabey mtDNA.

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Simian foamy viruses (SFVs) are thought to infect virtually any adult nonhuman primate (NHP). While many data have accumulated about patterns of codivergence with their hosts and cross-species transmission events, little is known about the modalities of SFV transmission within NHP species, especially in the wild. Here we provide a detailed investigation of the dynamics of SFV circulation in a wild community of Western chimpanzees (Pan troglodytes verus).

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