Chikungunya Virus Research Articles

On the tracks of an uninvited guest, the Asian tiger mosquito, Aedes albopictus in Cyprus

BackgroundAedes albopictus, the Asian tiger mosquito, which is listed among the world's 100 most dangerous invasive species, is the main vector of chikungunya, dengue and Zika viruses. This mosquito species has rapidly dispersed and invaded much of the globe assisted by its life history traits and high propagule pressure driven by human activities. Aedes albopictus is currently widespread across mainland Europe and the Mediterranean region, including the islands. Cyprus remained free of Ae. albopictus until October 2022, when specimens were recorded for the first time in Limassol district, including the port area. Understanding the processes associated with the introduction, expansion and establishment of this vector in Cyprus is of primary importance to mitigate its dispersal on the island, and to implement control methods to prevent disease outbreaks. A genetic analysis of these invasive specimens collected in Limassol district and in areas from the Central Mediterranean was performed to obtain a genetic portrait of the demographic history of the invasive mosquitoes on Cyprus.MethodsWe applied highly polymorphic simple sequence repeat (SSR) markers to the Ae. albopictus mosquitoes collected in Cyprus and to specimens from Italy, France, Switzerland, the Balkans, Greece and Turkey to construct an SSR individual genotype dataset that would enable the invasion pattern of Ae. albopictus in Cyprus to be traced. Bayesian clustering analyses using STRUCTURE and BayesAss version 3 were employed to derive information on the degree of ancestry among Cypriot and Mediterranean mosquitoes and on recent mosquito movements both within Cyprus and between Cyprus and the Central Mediterranean areas.ResultsThe Cypriot mosquitoes appear to be highly polymorphic with no signs of genetic drift due to recent founder effects. An ongoing mosquito dispersal within the Limassol district was detected, suggesting the presence of established, hidden adventive populations. These mosquitoes share a high degree of ancestry with those in the Balkans and parts of northern Italy that border the Adriatic Sea.ConclusionsConsidering the trade connections of Limassol port, Cyprus with the Balkans and the Adriatic Italian region, we hypothesise that these areas may be involved in the incursion of Ae. albopictus into Cyprus. As the Balkan and Italian mosquitoes display high competence for CHIKV, questions arise about possible arbovirus outbreaks in Cyprus and highlight the need to implement surveillance and control measures.Graphical

Clinical manifestations associated with the chronic phase of Chikungunya Fever: A systematic review of prevalence.

The aim of this systematic review of prevalence is to observe and discuss the clinical manifestations of Chikungunya Virus disease in its chronic phase. To be eligible, the observational studies should accompany the individuals for at least six months. The research was conducted using electronic databases MEDLINE and EMBASE. The methodological quality was evaluated using the "Joanna Briggs Institute's critical appraisal checklist for studies reporting prevalence data" tool. The search has found 175 articles. The application of the inclusion criteria defined a total of 29 selected studies. From the included studies, only one did not present arthralgia as a prevalent symptom in the chronic phase. Other signs and symptoms observed were: fatigue; sleep disorders; myalgia; skin lesions; depression; digestive disorders. Because it is an often incapacitating symptom, arthralgia can affect the individuals' quality of life, with implications in their social and work life. Since the chronic phase is common in infected individuals, all levels of health care should be prepared to monitor, in the medium to long term, the patients affected by this condition.

Novel α-mangostin derivatives as promising antiviral agents: Isolation, synthesis, and evaluation against chikungunya virus.

Investigations into fruit and vegetable processing residues (FVPRs) offer huge opportunities to discover novel therapeutics against many diseases. In this study, detailed investigation of Garcinia mangostana fruit peel extract led to the isolation and identification of ten known compounds (1-10). Further, a new series of α-mangostin derived sulphonyl piperzines, aryl alkynes and 1,2,3-triazole derivatives were synthesized using Huisgen 1,3-dipolar cyclo-addition reaction ("click" chemistry). Both isolated compounds and synthetic derivatives were evaluated for their anti-chikungunya activity (CHIKV). Isolated compounds, gartanin (1), mangostenone-F (4), 1-isomangostin (5), mangostenone-D (6), epicatechin (7) and derivatives 14, 15c, 15d, 15e, 15f, 17d, 17f, and 18h exerted anti-CHIKV activity. Compounds 17d, 17f and 18h manifested higher antiviral activity (>2 log reduction in virus titer) with a selectivity index (SI)>50. The compounds with higher antiviral activity were evaluated further with various assays, time of addition assay, entry and entry bypass assay and were also subjected to molecular docking with viral proteins. The results revealed that 17d, 17f and 18h affect multiple stages of virus life cycle through probable interaction with envelope proteins and nsP3 macrodomain of CHIKV. Overall, this study provides evidence for anti-CHIKV activity of natural xanthones from Garcinia mangostana L and their derivatives which could be further investigated for development of therapeutics against chikungunya.

Cellular takeover: How new world alphaviruses impact host organelle function.

Alphavirus replication is dependent on host cell organelles to facilitate multiple steps of the viral life cycle. New world alphaviruses (NWA) consisting of eastern, western and Venezuelan equine encephalitis viruses are a subgroup of alphaviruses associated with central nervous system disease. Despite differing morbidity and mortality amongst these viruses, all are important human pathogens due to their transmission through viral aerosolization and mosquito transmission. In this review, we summarize the utilization of host organelles for NWA replication and the subversion of the host innate immune responses. The impact of viral proteins and replication processes on organelle function is also discussed. Literature involving old world alphaviruses (OWA), such as chikungunya virus and Sindbis virus, is included to compare and contrast between OWA and NWA and highlight gaps in knowledge for NWA. Finally, potential targets for therapeutics or vaccine candidates are highlighted with a focus on host-directed therapeutics.

Phylogeographic Characterization of Aedes albopictus (Skuse, 1894) in Algeria.

Aedes albopictus, known as the Asian tiger mosquito, is an extensively studied mosquito species recognized for its rapid global expansion and its capacity to transmit a range of viruses such as dengue, chikungunya, Zika, and yellow fever viruses. In 2010, Ae. albopictus was observed for the first time in Tizi-Ouzou, Algeria, and since then has colonized all the northern part of the country until the semi-arid areas. The present study was devoted to the molecular characterization of Ae. albopictus in Algeria. A total of 20 selected mosquitos,originated from collected eggs in five different districts of northern Algeria weretested by PCR amplification and sequencing of the Cytochrome c oxidase subunit 1 a (COIa). Pairwise alignment of the obtained sequences with representative Ae. albopictus available COIasequences of the world exhibit 117 different haplotypes. The Algerian sequences are grouped in 1 haplotype shared with Morroco, Madagascar and Mauritius in Africa and 3 other continents (Asia, Europe and America). Asia expresses the highest genetic and nucleotidic diversity (Hd = 0.828;π = 0.0144). In China two new species not described in the literature and confused with Ae. albopictus are detected. These results could be used as preliminary data to study and develop targeted control strategies to prevent this vector from spreading in Algeria.

A brief overview of chikungunya-related pain.

Pain is an important symptom associated with the arboviral disease caused by the Chikungunya virus (CHIKV). For a significant number of patients, this symptom can persist for months or even years, negatively affecting their quality of life. Unfortunately, pharmacological options for this condition are limited and only partially effective, as the underlying mechanisms associated with CHIKV-induced pain are still poorly understood. The re-emergence of CHIKV has led to new outbreaks, and the expected high prevalence of pain in these global events requires new scientific advances to find more effective solutions. Here we review the main aspects of pain caused by CHIKV infection, such as the anatomy of the affected sites, the prevalence and management of this symptom, the diversity of possible cellular and molecular mechanisms, and finally highlight a promising meningeal pathway to elucidate the mechanisms involved in the unsolved problem of CHIKV-associated pain.

The Chikungunya Virus nsP3 Macro Domain Inhibits Activation of the NF-κB Pathway

The role of the chikungunya virus (CHIKV) non-structural protein 3 (nsP3) in the virus lifecycle is poorly understood. The protein comprises three domains. At the N-terminus is a macro domain, biochemically characterised to bind both RNA and ADP-ribose and to possess ADP-ribosyl hydrolase activity—an enzymatic activity that removes ADP-ribose from mono-ADP-ribosylated proteins. As ADP-ribosylation is important in the signalling pathway, leading to activation of the transcription factor NF-κB, we sought to determine whether the macro domain might perturb NF-κB signalling. We first showed that CHIKV infection did not induce NF-κB activation and could not block exogenous activation of the pathway via TNFα, although TNFα treatment did result in a modest reduction in virus titre. In contrast, ectopic expression of nsP3 was able to inhibit both basal and TNFα-mediated NF-κB activation, and this was dependent on the macro domain, as a mutation previously shown to disrupt ADP-ribose binding and hydrolase activity (D10A) eliminated the ability to inhibit NF-κB activation. The macro domain D10A mutant also resulted in a dramatic reduction in virus infectivity, consistent with the notion that the ability of the macro domain to inhibit NF-κB activation plays a role in the virus lifecycle.

Chikungunya virus infection in the skin: histopathology and cutaneous immunological response

Alphavirus chikungunya virus (CHIKV) is an arbovirus, belonging to the Togaviridae family. The disease caused by CHIKV generally evolves with spontaneous resolution in a few weeks; however, progression to a chronic disease may occur. The most common symptoms are fever, myalgia, and arthralgia; however, skin manifestations may occur in 40 to 80% of infected individuals. Morbilliform and maculopapular erythematous eruptions, vesiculobullous lesions, generalized erythema, maculopapular eruption and skin peeling, hypermelanosis, painful oral lesions, and urticarial lesions have been reported. Usually, these manifestations disappear, but they can become sequelae. Since the skin is the first line of defense against CHIKV infection, in this study, we aimed to investigate the immunohistopathological aspects of the skin of infected individuals during the acute phase of the disease by performing histopathological and ultrastructural analysis, detection and quantification of the viral genome, detection of viral antigen and immune cells, and cytokines/chemokines’ characterization. The main histopathological findings were perivascular and inflammatory infiltrates, blood capillary ectasia, and interstitial edema. The immunohistochemistry revealed CHIKV antigen in the epidermis, endothelial cells, fibroblasts, and macrophages in the reticular and papillary dermis; inflammatory cells infiltrate; arrector pili muscle; sweat and sebaceous glands; and hair follicle. Moreover, inflammatory infiltrates were composed of lymphocytes (CD4+ and CD8+) and macrophages (CD68+) in the dermis and perivascular infiltrate. TNF-α, IL-6, RANTES, and VEGFR2 were expressed in the epidermis, blood vessels, sweat glands, and migrating cells. Loss of contact among adjacent keratinocytes, epidermis presenting necrotic cells, and fibroblasts with dilated cisternae in the endoplasmic reticulum and mitochondria with few cristae was observed by transmission electron microscopy. Studies involving skin immunopathogenesis during CHIKV infection are still scarce; therefore, the findings presented here can contribute to a better understanding of the disease immunopathogenesis.

Seroprevalence of dengue, Zika, and chikungunya in São Sebastião, Brazil (2020–2021): a population-based survey

BackgroundUrban arboviruses pose a significant global burden, particularly in tropical regions like Brazil. São Sebastião, a lower-middle-class urban area just 26 km from the Brazilian capital, is an endemic area for dengue. However, asymptomatic cases may obscure the actual extent of the disease. In this study, we measured the seroprevalence of dengue, Zika virus, and chikungunya, and compared these findings with surveillance data.MethodsA cross-sectional study was conducted involving 1,535 households. ELISA serological tests were performed to detect IgM and IgG antibodies against dengue, Zika virus, and chikungunya. History of previous exposure to arboviruses, data on age, gender, and education level were collected through a questionnaire. Participants who tested positive for IgM and/or IgG were classified as soropositive. Statistical analyses included tests for normality, associations, mean comparisons, and correlations. Positive serological results were compared with cases captured by local epidemiological surveillance.ResultsThe study included 1,405 individuals, divided into two groups related to pre-pandemic and pandemic COVID-19 phases. Among participants, 0.7% to 28.8% self-reported history of dengue, Zika, or chikungunya. However, the estimated overall seroprevalence was 64.3% (95% CI: 61.8–66.7) for dengue virus, 51.4% (95% CI: 48.8–53.9) for Zika virus, and 5.4% (95% CI: 4.4–6.7) for chikungunya virus. Multiple arboviruses were noted at 4.0% (95% CI: 3.1–5.1). Advancing age and lower education were associated with higher exposure to arboviruses (p < 0.05). The estimated number of urban arboviral infections was 84 times higher than reported cases.ConclusionsThe large gap between seroprevalence estimates and cases captured by epidemiological surveillance suggests a silent circulation of arboviruses, highlighting the need for comprehensive serological surveys in endemic regions. Addressing these discrepancies is crucial for effective resource allocation and implementation of public health interventions.

The Hsf1-sHsp cascade has pan-antiviral activity in mosquito cells

Aedes mosquitoes transmit pathogenic arthropod-borne (arbo) viruses, putting nearly half the world’s population at risk. Blocking virus replication in mosquitoes is a promising approach to prevent arbovirus transmission, the development of which requires in-depth knowledge of virus-host interactions and mosquito immunity. By integrating multi-omics data, we find that heat shock factor 1 (Hsf1) regulates eight small heat shock protein (sHsp) genes within one topologically associated domain in the genome of the Aedes aegypti mosquito. This Hsf1-sHsp cascade acts as an early response against chikungunya virus infection and shows pan-antiviral activity against chikungunya, Sindbis, and dengue virus as well as the insect-specific Agua Salud alphavirus in Ae. aegypti cells and against chikungunya virus and O’nyong-nyong virus in Aedes albopictus and Anopheles gambiae cells, respectively. Our comprehensive in vitro data suggest that Hsf1 could serve as a promising target for the development of novel intervention strategies to limit arbovirus transmission by mosquitoes.

Combinations of approved oral nucleoside analogues confer potent suppression of alphaviruses in vitro and in vivo.

Alphaviruses such as chikungunya virus (CHIKV) pose a significant threat to global health, yet specific antiviral therapies remain unavailable. In this study, we evaluated combinations of three approved oral directly acting antiviral (DAA) drugs (sofosbuvir (SOF), molnupiravir (MPV) and favipiravir (FAV)) against CHIKV, Semliki Forest virus (SFV), Sindbis virus (SINV), and Venezuelan Equine Encephalitis virus (VEEV) in vitro and in vivo . In human skin fibroblasts, synergistic antiviral effects were observed for the drug combinations MPV + SOF and FAV + SOF against CHIKV, and for FAV + SOF against SFV. In human liver Huh7 cells, the combinations of FAV + MPV conferred additive to synergistic activity against VEEV and SINV strains, while SOF synergized with FAV against SINV strains. In a mouse model of CHIKV arthritis, MPV improved CHIKV-induced foot swelling and reduced systemic infectious virus titers. Combination treatment with suboptimal doses of MPV and SOF significantly reduced foot swelling and decreased infectious virus titers in serum as compared to single doses of each drug. Sequencing of CHIKV RNA from mouse joint tissue revealed that MPV caused dose-dependent increases in mutations in the CHIKV genome. Upon combination therapy of MPV with SOF, the number of mutations was significantly lower compared to single treatment with several higher doses of MPV. In summary, combining approved oral nucleoside analogs confers potent suppression of multiple alphaviruses in vitro and in vivo with enhanced control of viral genetic evolution in the face of antiviral drug pressure. These drug combinations may ultimately lead to the development of potent combinations of pan-family alphavirus inhibitors.

Rising Incidence and Spatiotemporal Dynamics of Emerging and Reemerging Arboviruses in Brazil

Background: Brazil has witnessed the co-circulation of dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV), with outbreaks exacerbated by environmental factors, social determinants, and poor sanitation. The recent re-emergence of Oropouche virus (OROV) has added complexity to vector control strategies, emphasizing the need for integrated approaches to curb arboviruses spread. We aimed to analyze temporal trends and spatial distributions with national scope of these emerging arboviruses. Methods: An ecological study using data from the Brazilian Notifiable Diseases Information System the period from 2023 to 2024 was undertaken. Temporal trends were evaluated using Joinpoint regression, while spatial analysis was conducted using Moran’s I, and local indicators of spatial association. Results: Dengue fever cases increased by 322%, while Oropouche fever (OF) increased by 300%. The states of Amazonas and Espírito Santo reported increases in OF cases. Moran’s I test revealed spatial clustering of DENV and CHIKV. Two municipalities in the state of Mato Grosso do Sul showed cocirculation of DENV, CHIKV, and ZIKV. Conclusions: This study identified a surge in arbovirus cases between 2023 and 2024, with peak incidences from January to March and October to December, linked to favorable climatic conditions. Clustering patterns and co-circulation of arboviruses highlight the need for tailored control and prevention strategies and targeted interventions to mitigate their impact.

Structural and Functional Analysis of Hemoglobin Binding to the Peritrophic Matrix During Blood Digestion in Aedes aegypti

The Aedes aegypti mosquito is responsible for transmitting pathogens such as the Dengue, Zika, and Chikungunya viruses. The peritrophic matrix (PM) is an extracellular chitin-rich structure that lines the midgut of arthropods, providing a crucial protective barrier for the gut epithelium against mechanical damage, ingested pathogens, and toxic substances. During blood digestion, hemoglobin is lysed, releasing free heme into the midgut lumen. Part of this heme binds strongly to the PM, mitigating its harmful effects on the mosquito epithelial cells. Our study focused on investigating the interaction dynamic between hemoglobin and the PM during blood digestion in A. aegypti. Optical microscopy was employed to observe the temporal progression of blood digestion in the A. aegypti midgut, highlighting significant morphological changes in the blood bolus. An electrophoresis analysis revealed distinct protein bands in the PM extract, some of which were associated with hemoglobin and its subunits. The presence of PM-associated hemoglobin was confirmed by amino-terminal sequencing and an immunoblot analysis using anti-hemoglobin antibodies. Furthermore, fluorescence microscopy revealed overlapping labeling between hemoglobin and chitin, suggesting an interaction between hemoglobin and PM chitin. Corroborating these results, hemoglobin showed an affinity with chitin in the chromatography and molecular docking assays, in which the hemoglobin subunits interacted with the oligosaccharide (NAG)4. Thus, hemoglobin may perform a function similar to that of peritrophins. Further experiments demonstrated the protective role of the PM against hemoglobin proteolysis during blood digestion. Overall, this study provides valuable insights into the intricate interactions between hemoglobin and the PM, enhancing our understanding of mosquito digestive physiology and potentially contributing to the development of vector control strategies.

Old World alphaviruses use distinct mechanisms to infect brain microvascular endothelial cells for neuroinvasion.

Several alphaviruses bypass the blood-brain barrier (BBB), causing debilitating or fatal encephalitis. Sindbis virus (SINV) has been extensively studied in vivo to understand alphavirus neuropathogenesis; yet the molecular details of neuroinvasion at the BBB remain poorly understood. We investigated alphavirus-BBB interactions by pairing a physiologically relevant, human pluripotent stem cell derived model of brain microvascular endothelial cells (BMECs) with SINV strains of opposite neuroinvasiveness. Our system demonstrates that SINV neuroinvasion correlates with robust infection of the BBB. Specifically, SINV genetic determinants of neuroinvasion enhance viral entry into BMECs. We also identify solute carrier family 2 member 3 (SLC2A3, also named GLUT3) as a potential BMEC-specific entry factor exploited for neuroinvasion. Strikingly, efficient BBB infection is a conserved phenotype that correlates with the neuroinvasive capacity of several Old World alphaviruses, including chikungunya virus. Here, we reveal BBB infection as a shared pathway for alphavirus neuroinvasion that can be targeted for preventing alphavirus-induced encephalitis.

Chikungunya Particle and RNA Induce Mechanical and Heat Hypersensitivities in a TRPV1-Dependent Manner

Chikungunya virus (CHIKV), the causative agent of the chikungunya fever, is an alphavirus widely transmitted by the bite of the female mosquito of the genus Aedes sp., especially in tropical and subtropical regions. Brazil is the country most affected by the microorganism. CHIKV classically induces articular pain, which can become long lasting for even years in a great number of the infected individuals, reducing their quality of life. The mechanisms of CHIKV-induced pain are poorly understood, but recent evidence indicated a role for the transient receptor potential vanilloid 1 (TRPV1) in this pathology. Herein, we assessed the ability of intra-articularly injected inactivated CHIKV or its RNA to trigger nociception in mice. Both stimuli induced bilateral secondary hyperalgesia to mechanical and heat stimuli. These responses were attenuated by TRPV1 ablation or antagonism. Joint structural alterations and increased cartilage TRPV1 protein expression were detected in the ipsilateral knee joints injected with either CHIKV or viral RNA. However, the lack of this receptor did not influence the histological changes triggered by CHIKV or RNA. The results further support the role of TRPV1 in CHIKV-induced pain and highlight its importance in the chronic phase of the disease.

Modeling chikungunya virus infection with Black–Karasinski process: stationary distribution, probability density function, and extinction

Incorporating stochastic processes into biological models is crucial for capturing the inherent variability and uncertainties within biological systems. This paper explores the benefits of introducing Black–Karasinski process into chikungunya virus infection modeling. By utilizing the Black–Karasinski process researchers can capture the inherent variability in biological processes and account for uncertainties. This paper highlights the advantages of Black–Karasinski processes in biological modeling. We investigate the dynamical behavior of a stochastic model for chikungunya virus infection incorporating a Black–Karasinski process. Firstly, we establish sufficient conditions for the existence of a stationary distribution in the model. By solving the corresponding Fokker–Planck equation we obtain the local probability density function near the quasi-endemic equilibrium, which provides insights into the statistical characteristics of the stochastic system. Additionally, we present sufficient conditions for the extinction of infected host cells and chikungunya virus particles. Finally, we supplement the analytical results with numerical simulations to investigate the impact of random noise.

Arbovirus exposure and subclinical myocardial dysfunction in an Indigenous population in Northeast Brazil: a cross-sectional study

BackgroundHuman activities, such as urbanization and climate change, have facilitated the spread of arbovirus-carrying vectors, disproportionately affecting vulnerable traditional Indigenous communities.ObjectiveTo explore the relationships between subclinical myocardial dysfunction, assessed by global longitudinal strain (GLS), and comprehensive arbovirus serology in an Indigenous population, while also describing the serological and epidemiological profile of dengue, chikungunya, and Zika viruses.MethodsThis ancillary study is part of the first phase (2016–2017) of the Project of Atherosclerosis among Indigenous Populations (PAI), a cross-sectional study involving participants from two Indigenous communities with different degrees of urbanization and a highly urbanized city in Northeast Brazil. We assessed the seroprevalence of dengue, chikungunya, and Zika viruses in the Fulni-ô Indigenous community, the less urbanized and most traditional group. Additionally, we explored the relationship between these viruses and subclinical heart disease, assessed by speckle-tracking echocardiography-derived GLS.ResultsOne hundred seventy-four participants were included, with a median age of 45.0 years (interquartile range 38.0–55.0). The majority were female (58.6%; n = 102). The prevalence of anti-ZIKV IgG was 95.3%; anti-DENV IgG was 85.8%, and anti-CHIKV IgG was 70.9%. GLS abnormalities were detected in nearly half (48.3%) of the cohort. However, no significant association was found between arbovirus serology and GLS.ConclusionsThe findings reveal a high prevalence of positive serology for arboviruses and a significant rate of subclinical cardiac dysfunction. There was no significant association between reduced left ventricular longitudinal strain and positive arbovirus serology, likely due to the limited number of participants with indications of acute contact with the viruses studied. However, the unprecedented and relevant results of this study are noteworthy, as they address critical public health issues, particularly in vulnerable populations. Further research is needed to explore these findings in more depth.

A Roadmap Towards the Identification and Validation of Conserved T Cell Epitope Regions in Viral Pathogen Families with Pandemic Potential.

The SARS-CoV-2 pandemic has highlighted the need for society, as a whole, to be prepared against potential pandemics caused by a variety of different viral families of concern. Here, we describe a roadmap towards the identification and validation of conserved T cell epitope regions from Viral Families of Pandemic Potential (VFPP). For each viral family, we select a prototype virus, the sequence of which could be utilized in epitope identification screens. Examples of viral families considered and their respective prototypes (species/ subspecies) are Coronaviridae (Severe Acute Respiratory Syndrome-related Coronavirus/ SARS-CoV-2), Flaviviridae (Dengue virus/DENV2), Togaviridae (Chikungunya virus/ CHIKV), Paramyixoviridae (Morbillivirus/measles), Arenaviridae (Mammarenavirus/ Lassa), and Picornaviridae (Enterovirus C/poliovirus). The peptide sequences encoded in each prototype virus are then analyzed to determine their conservation across different viral taxonomic groups and viral variants derived from each of the VFPP. We outline available methodologies for epitope discovery based on panels of overlapping peptides and bioinformatics- based predictions of HLA-peptide binding, along with high-throughput in vitro assays, with emphasis on addressing coverage of the general worldwide population. Validation can be achieved by a variety of methodologies, including determining HLA restriction and recognition in samples from volunteers convalescent from previous infections or immunized with approved or experimental vaccines, and immunophenotyping of responding T cells. The capacity of these regions to induce crossreactive T cell responses can be tested experimentally with homologous peptides derived from the various viral species of interest. Importantly, they could be considered as a component of pan-viral family vaccines. Conversely, immunogenic regions that are highly specific to a given virus could be of interest for diagnostic applications.

Susceptibility to organophosphate insecticides in Aedes aegypti (Diptera: Culicidae) from northern Colombia and associated resistance mechanisms

BackgroundAedes aegypti is the primary vector of dengue, chikungunya, and Zika viruses in Colombia. Various insecticides, including pyrethroid, organophosphate, and carbamate insecticides; growth regulators; and biological insecticides, such as Bacillus thuringiensis var. israelensis, have been used to control Ae. aegypti populations. However, organophosphates such as malathion, pirimiphos-methyl, and temephos have been used over the last decade owing to the high resistance to pyrethroids.MethodsThis study assessed the susceptibility to organophosphates in 14 Ae. aegypti populations from the Córdoba department in northern Colombia. Moreover, possible resistance mechanisms were investigated by determining the activity levels of α-esterases, β-esterases, mixed function oxidases (MFOs), glutathione S-transferases (GSTs), and insensitive acetylcholinesterase (iAChE). Additionally, the Ace-1 gene was sequenced to identify mutations at the target site of action.ResultsThe populations were susceptible to temephos and malathion but resistant to fenitrothion, and in three of them, to pirimiphos-methyl. Alterations in the enzyme activity levels of α-esterases and β-esterases, GST, and iAChE were observed among the populations, with high enzyme activity levels of α and β esterases associated with resistance to fenitrothion. No mutations were identified in the Ace-1 gene.ConclusionsThese findings are highly relevant for vector control programs in the region, as they allow for adjustments in resistance management strategies and improve the effectiveness of interventions against these arboviruses.Graphical

Mutations in chikungunya virus nsP4 decrease viral fitness and sensitivity to the broad-spectrum antiviral 4'-Fluorouridine.

Chikungunya virus (CHIKV) is an arthritogenic alphavirus that has re-emerged to cause large outbreaks of human infections worldwide. There are currently no approved antivirals for treatment of CHIKV infection. Recently, we reported that the ribonucleoside analog 4'-fluorouridine (4'-FlU) is a highly potent inhibitor of CHIKV replication, and targets the viral nsP4 RNA dependent RNA polymerase. In mouse models, oral therapy with 4'-FlU diminished viral tissue burdens and virus-induced disease signs. To provide critical evidence for the potential of 4'-FlU as a CHIKV antiviral, here we selected for CHIKV variants with decreased 4'-FlU sensitivity, identifying two pairs of mutations in nsP2 and nsP4. The nsP4 mutations Q192L and C483Y were predominantly responsible for reduced sensitivity. These variants were still inhibited by higher concentrations of 4'-FlU, and the mutations did not change nsP4 fidelity or provide a virus fitness advantage in vitro or in vivo. Pathogenesis studies in mice showed that the nsP4-C483Y variant caused similar disease and viral tissue burden as WT CHIKV, while the nsP4-Q192L variant was strongly attenuated. Together these results support the potential of 4'-FlU to be an important antiviral against CHIKV.