Publications by authors named "Scott C Weaver"
Eilat (EILV)/chikungunya virus (CHIKV), an insect-based chimeric alphavirus was previously reported to protect mice months after a single dose vaccination. The underlying mechanisms of host protection are not clearly defined. Here, we assessed the capacity of EILV/CHIKV to induce quick and durable protection in cynomolgus macaques.
View Article and Find Full Text PDFZika virus (ZIKV) is an arbovirus associated with neurological disorders accompanying congenital infections. With no vaccine or antiviral approved, there is an urgent need for the development of effective antiviral agents against ZIKV infection. We evaluated the anti-ZIKV and immunomodulatory activity of ouabain, a Na/K-ATPase inhibitor known to have immunomodulatory and antiviral activities, using human neural stem/progenitor cells (hNS/PCs) and a murine model of congenital Zika syndrome (CZS).
View Article and Find Full Text PDFNaturally circulating strains of eastern equine encephalitis virus (EEEV) bind heparan sulfate (HS) receptors and this interaction has been linked to its neurovirulence. Previous studies associated EEEV-HS interactions with three positively charged amino acid clusters on the E2 glycoprotein. One of these sites has recently been reported to be critical for binding EEEV to very-low-density lipoprotein receptor (VLDLR), an EEEV receptor protein.
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- Recent yellow fever outbreaks in Brazil were linked to mosquito transmission but showed no human outbreaks due to a lack of vaccination and presence of Aedes aegypti mosquitoes.
- The study tested if immunity from dengue and Zika viruses impacts yellow fever virus (YFV) spread in monkeys, finding that prior infections reduced YFV levels in the blood.
- These findings suggest that immunity from other flaviviruses might help prevent the amplification and spread of yellow fever in populations already exposed to dengue and Zika.
Madariaga virus (MADV) and Venezuelan equine encephalitis virus (VEEV) are emerging arboviruses affecting rural and remote areas of Latin America. However, clinical and epidemiologic reports are limited, and outbreaks are occurring at an increasing frequency. We addressed the data gap by analyzing all available clinical and epidemiologic data of MADV and VEEV infections recorded since 1961 in Panama.
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- The study explores the resurgence of Oropouche fever in Brazil from 2023 to 2024, focusing on virological factors influencing the outbreak after decades of sporadic cases.
- Researchers gathered data from various sources, analyzed serum samples from patients and previously infected individuals, and performed molecular tests to understand the virus's characteristics and behavior.
- The findings showed an extraordinary spike in cases in 2024, with over 8,600 confirmed incidents, highlighting the virus's widespread distribution across all regions of Brazil.
Chikungunya virus (CHIKV) was isolated from humans in an outbreak of a febrile illness during July and August 2015 in the central valleys of Chiapas, Mexico. Sera obtained from 80 patients were tested for CHIKV RNA by reverse transcriptase polymerase chain reaction (RT-PCR) and for IgM and IgG antibodies by an enzyme linked immunoassay and a commercial indirect immunofluorescence test for CHIKV and dengue virus (DENV). Of the 80 patients, 67 were positive, including 50 for RNA and 17 for IgM.
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- First-generation COVID-19 vaccines based on the spike (S) protein have decreased in effectiveness against new Omicron variants, highlighting the need for more broadly protective vaccines.
- Researchers developed a new mRNA vaccine targeting the nucleocapsid (N) protein and tested its efficacy alone and in combination with the existing S-based vaccine in hamsters.
- Results showed that the combined mRNA vaccines (mRNA-S+N) provided complete protection against Omicron variants, suggesting their potential as a comprehensive COVID-19 vaccine.
Article Synopsis
- Western equine encephalitis virus (WEEV) caused a significant outbreak in Argentina and Uruguay from December 2023 to April 2024, with 217 human cases and 2,548 equine cases reported.
- The investigation focused on the Rio Grande do Sul state border area between Argentina and Uruguay, utilizing epidemiologic, entomological, and genomic methods to analyze the outbreak.
- A novel lineage of the virus, proposed as lineage C, was identified in three fatal equine cases, emphasizing the need for ongoing monitoring and equine vaccination to prevent future outbreaks.
Article Synopsis
- * The study included data from 2015 to 2024, revealing a dramatic rise in infections—83.2% occurring in the North—and identified a novel OROV strain that is much more virulent than the original prototype.
- * The new OROV strain was shown to replicate significantly faster and more effectively in mammalian cells, with a notable decrease in neutralizing antibodies from individuals previously infected, indicating a potential threat to public health.
Article Synopsis
- Western equine encephalitis virus (WEEV) used to cause significant outbreaks in humans and horses but has become less virulent over time, raising questions about the reasons for this change and the potential for re-emergence of deadly strains.
- Researchers identified protocadherin 10 (PCDH10) as a key receptor for WEEV, which ancient strains could bind to, while contemporary strains show reduced binding abilities indicating a shift in the virus’s host adaptation.
- The study suggests that PCDH10 not only facilitates infection in neurons but also that a soluble form can protect against WEEV, offering insights for future medical treatments and risk assessments of the virus.
Article Synopsis
- - The study focuses on Acute Undifferentiated Febrile Illnesses (AUFIs) in Latin America, aiming to improve understanding of their causes and facilitate outbreak detection, which is currently limited by inadequate diagnostics and fragmented healthcare systems.
- - A collaborative research protocol involving institutions from several countries will collect clinical data and samples from patients with fever lasting less than 8 days, specifically targeting viral, bacterial, and parasitic pathogens.
- - The research team will analyze blood and other specimens using advanced testing methods, with findings aimed to be shared with health authorities to enhance public health responses to AUFIs.
Article Synopsis
- A seroprevalence survey in Bangladesh revealed that 2.4% of individuals tested positive for chikungunya virus (CHIKV) before a major epidemic in 2017.
- Factors significantly linked to CHIKV seropositivity included having a prior infection with dengue virus, being male, and the presence of Aedes aegypti mosquitoes in the community.
- The study estimated that nearly 5 million people in Bangladesh may have been previously infected with CHIKV, suggesting high susceptibility among the population prior to the outbreak.
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- Chikungunya virus has led to millions of infections globally in the last two decades, with a recent outbreak in the Kedougou region of Senegal, West Africa.
- Genomic studies indicate that the 2023 epidemic in Kedougou is not a result of a new introduction of the virus but rather a resurgence of a previously established strain.
- This endemic strain is evolving over time within a natural environment, suggesting a complex interaction with local ecosystems.
Article Synopsis
- - SARS-CoV-2 is continuously evolving, posing challenges to existing vaccines and treatments, which has led to the development of a new pipeline for creating effective VHH antibodies and bispecifics to neutralize various virus variants.
- - High-affinity VHH antibodies were discovered through targeted phage library techniques, resulting in a bispecific construct that effectively combats multiple SARS-CoV-2 variants, showing enhanced resistance to antigenic escape.
- - The new tetravalent bispecific platform enables speedy development and production of antibodies, providing flexible and potent responses to emerging variants, making it a promising method for ongoing viral management.
Article Synopsis
- * Researchers studied the effects of pre-existing immunity from related viruses like dengue (DENV) and Zika (ZIKV) on YFV infection using a mouse model.
- * Findings indicate that immunity from DENV-2 and ZIKV can significantly reduce YFV levels in mice, mostly through humoral immune responses, suggesting a need to reevaluate YFV outbreak risks considering existing flavivirus immunity.
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- A serosurvey in Senegal from 2020-2023 examined chikungunya virus (CHIKV) exposure in fruit bats.
- Out of 671 bats tested, 13.3% showed exposure to CHIKV IgG, with the highest rates found in Eidolon helvum (18.3%) and Epomophorus gambianus (13.7%).
- The findings indicate that these bat species are naturally exposed to the chikungunya virus.
Article Synopsis
- Chikungunya virus (CHIKV) is causing increasing public health concerns, highlighting the need for effective vaccination strategies to prevent its associated symptoms and future outbreaks.
- Researchers studied a chimeric virus, Eilat (EILV)/CHIKV, which doesn’t replicate in vertebrates but has shown promise in inducing strong protective immunity in mice and now shows effective protection in cynomolgus macaques.
- The chimeric virus not only provided rapid protection against wild-type CHIKV infection but also triggered robust immune responses with no adverse reactions, suggesting it is a safe and effective vaccine for long-lasting protection.
Article Synopsis
- A recent outbreak of western equine encephalitis virus (WEEV) has been reported in South America, particularly in Brazil, where three horses have died from the infection.
- Researchers sequenced the WEEV strains and discovered a new lineage responsible for these fatalities.
- To reduce the impact of WEEV, ongoing monitoring and vaccination of horses are essential.
We detected Mayaro virus (MAYV) in 3.4% (28/822) of febrile patients tested during 2018-2021 from Roraima State, Brazil. We also isolated MAYV strains and confirmed that these cases were caused by genotype D.
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- Ilhéus virus (ILHV) is an arbovirus found in Central and South America and the Caribbean, first identified in 1944, with limited studies on its pathogenesis and vector competence.
- Researchers developed a murine model to study ILHV, demonstrating that it can cause severe neurological disease in mice, particularly in immunocompromised and age-specific groups.
- The virus was shown to replicate efficiently in various vertebrate and invertebrate cell lines, and studies suggest that certain mosquito species can effectively transmit ILHV, indicating a risk of the virus emerging in new regions.
Article Synopsis
- * The outbreak suggests that the current strains of the virus may not need significant changes to spread in populated areas.
- * To prevent future dengue infections in Senegal, it's crucial to implement extensive genomic surveillance and improve molecular diagnostic methods.
Article Synopsis
- G3BP1 and G3BP2 are proteins that help form stress granules in cells during stress, like viral infections, but SARS-CoV-2's nucleocapsid (N) protein stops this process.
- The study identifies a specific mutation (N-F17A) in the N protein that prevents its interaction with G3BP1/2, leading to an inability to inhibit stress granule formation.
- This disruption results in lower viral replication and reduced illness in experimental models, showing that the G3BP1-N interaction is crucial for SARS-CoV-2’s ability to replicate and cause disease.
Effects of climate change and human activities on vector-borne diseases.
Nat Rev Microbiol
August 2024
Article Synopsis
- Vector-borne diseases, spread by blood-feeding arthropods like mosquitoes and ticks, significantly impact global health, especially in tropical and subtropical regions.
- Climate change affects these vectors' reproduction and distribution, which in turn influences disease transmission, but the outcomes are often complex and can vary widely.
- The discussion in this Review includes how factors such as climate, land use, and human movement contribute to the changing patterns of vectors and their associated diseases around the world.