Search Results (1,569)

Aedes albopictus is considered one of the major invasive species in the world and can transmit viruses such as dengue, Zika, or chikungunya. The Sterile Insect Technique (SIT) can be used to suppress the native populations of Ae. albopictus. Mark–release–recapture (MRR) studies are crucial to support the development of the release strategy during the SIT application. Meanwhile, weather conditions can affect the MRR trial’s results and it is critical to understand the influence of climatic factors on the results. In October 2022, 84,000 irradiated sterile males were released for three consecutive weeks in Faro, Southern Portugal. Mosquitoes were recaptured by human landing collection (HLC) one, two, four, and six days after release. Generalized linear models with a negative binomial family and log function were used to estimate the factors associated with the number of recaptured mosquitoes, prevalence ratios, and the 95% confidence intervals (CIs). A total of 84,000 sterile male mosquitoes were released, with 528 recaptured (0.8%) by HLC. The prevalence of recaptured mosquitoes was 23% lower when the wind intensity was moderate. Marked sterile males had an average median distance travelled of 88.7 m. The median probability of daily survival and the average life expectancy were 61.6% and 2.1 days, respectively. The wild male population estimate was 443.33 males/ha. Despite no statistically significant association being found with humidity, temperature, and precipitation, it is important to consider weather conditions during MRR trial analyses to obtain the best determinant estimation and a more efficient application of the SIT in an integrated vector management program. Full article

This study examined the seropositivity of T. gondii and coinfections with other TORCH pathogens among pregnant women attending 17 Basic Health Units (UBS) in Araçatuba, SP, Brazil. Of the 711 pregnant women seen at these UBS, only 297 were tested for T. gondii. Of the women tested for T. gondii (n = 297), 26.9% had IgG antibodies, 6.7% had IgM, and 32.0% tested positive for either or both. Only 1.4% showed both IgG and IgM antibodies, while 67.7% were non-reactive. The seropositivity was 17.1% for syphilis, 63.2% for rubella, 0.9% for hepatitis C, 0.9% for dengue, 17.9% for COVID-19, and 0.9% for herpes simplex (types 1/2). Coinfections with syphilis, rubella, and herpes simplex were also noted. Higher education levels appeared to protect against T. gondii seropositivity. The findings highlight a significant prevalence of T. gondii among pregnant women, with variation across UBSs, pointing to socioeconomic, behavioral, and environmental factors as influential. We also observed co-occurrence with other infections, such as syphilis, rubella, and herpes simplex. The study underscores the need for targeted public health interventions to reduce the risks of congenital infections. Full article

This study aimed to identify the factors associated with all-cause in-hospital mortality in laboratory-confirmed dengue cases from 2020 to mid-2024. A nationwide retrospective cohort study was conducted in Mexico and data from 18,436 participants were analyzed. Risk ratios (RRs) and 95% confidence intervals (CIs), estimated using generalized linear regression models, were used to evaluate the factors associated with all-cause in-hospital mortality risk. The overall case–fatality rate was 17.5 per 1000. In the multiple model, compared to dengue virus (DENV) 1 infections, DENV-2 (RR = 1.81, 95% CI 1.15–2.86) and DENV-3 (RR = 1.87, 95% CI 1.19–2.92) were associated with increased mortality risk. Patient characteristics, such as increasing age (RR = 1.02, 95% CI 1.01–1.03), type 2 diabetes mellitus (RR = 2.07, 95% CI 1.45–2.96), and chronic kidney disease (RR = 3.35, 95% CI 2.03–5.51), were also associated with an increased risk of a fatal outcome. We documented the influence of both the virus and individual susceptibility on mortality risk, underscoring the need for a comprehensive public health strategy for dengue. Full article

Climate change is no longer a hypothetical problem in the Caribbean but a new reality to which regional public health systems must adapt. One of its significant impacts is the increased transmission of infectious diseases, such as dengue fever, which is endemic in the region, and the presence of the Aedes aegypti mosquito vector responsible for transmitting the disease. (1) Methods: To assess the association between climatic factors and human dengue virus infections in the Caribbean, we conducted a systematic review of published studies on MEDLINE and Web of Science databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. (2) Results: In total, 153 papers were identified, with 27 studies selected that met the inclusion criteria ranging from the northern and southern Caribbean. Rainfall/precipitation and vapor pressure had a strong positive association with dengue incidence, whereas the evidence for the impact of temperatures was mixed. (3) Conclusions: The interaction between climate and human dengue disease in the Caribbean is complex and influenced by multiple factors, including waste management, infrastructure risks, land use changes, and challenged public health systems. Thus, more detailed research is necessary to understand the complexity of dengue within the wider Caribbean and achieve better dengue disease management. Full article

West Nile Virus (WNV) poses a significant global public health threat as a mosquito-borne pathogen. While laboratory mouse models have historically played a crucial role in understanding virus biology, recent research has focused on utilizing immunocompromised models to study arboviruses like dengue and Zika viruses, particularly their interactions with Aedes aegypti mosquitoes. However, there has been a shortage of suitable mouse models for investigating WNV and St. Louis encephalitis virus interactions with their primary vectors, Culex spp. mosquitoes. Here, we establish the AG129 mouse (IFN α/β/γ R^−/−) as an effective vertebrate model for examining mosquito–WNV interactions. Following intraperitoneal injection, AG129 mice exhibited transient viremia lasting several days, peaking on the second or third day post-infection, which is sufficient to infect Culex quinquefasciatus mosquitoes during a blood meal. We also observed WNV replication in the midgut and dissemination to other tissues, including the fat body, in infected mosquitoes. Notably, infectious virions were present in the saliva of a viremic AG129 mouse 16 days post-exposure, indicating successful transmission capacity. These findings highlight the utility of AG129 mice for studying vector competence and WNV–mosquito interactions. Full article

The establishment of effective antiviral responses within host cells is intricately related to their metabolic status, shedding light on immunometabolism. In this study, we investigated the hypothesis that cellular reliance on glutamine metabolism contributes to the development of a potent antiviral response. We evaluated the antiviral response in the presence or absence of L-glutamine in the culture medium, revealing a bivalent response hinging on cellular metabolism. While certain interferon-stimulated genes (ISGs) exhibited higher expression in an oxidative phosphorylation (OXPHOS)-dependent manner, others were surprisingly upregulated in a glycolytic-dependent manner. This metabolic dichotomy was influenced in part by variations in interferon-β (IFN-β) expression. We initially demonstrated that the presence of L-glutamine induced an enhancement of OXPHOS in A549 cells. Furthermore, in cells either stimulated by poly:IC or infected with dengue virus and Zika virus, a marked increase in ISGs expression was observed in a dose-dependent manner with L-glutamine supplementation. Interestingly, our findings unveiled a metabolic dependency in the expression of specific ISGs. In particular, genes such as ISG54, ISG12 and ISG15 exhibited heightened expression in cells cultured with L-glutamine, corresponding to higher OXPHOS rates and IFN-β signaling. Conversely, the expression of viperin and 2′-5′-oligoadenylate synthetase 1 was inversely related to L-glutamine concentration, suggesting a glycolysis-dependent regulation, confirmed by inhibition experiments. This study highlights the intricate interplay between cellular metabolism, especially glutaminergic and glycolytic, and the establishment of the canonical antiviral response characterized by the expression of antiviral effectors, potentially paving the way for novel strategies to modulate antiviral responses through metabolic interventions. Full article

Dengue virus poses a significant global health challenge, particularly in tropical and subtropical regions. Despite the urgent demand for vaccines in the control of the disease, the two approved vaccines, Dengvaxia and TV003/TV005, there are current questions regarding their effectiveness due to an increased risk of antibody-dependent enhancement (ADE) and reduced protection. These challenges have underscored the need for further development of improved vaccines for Dengue Virus. This study presents a new design using an in silico approach to generate a more effective dengue vaccine. Initially, our design process began with the collection of Dengue polyprotein sequences from 10 representative countries worldwide. And then conserved fragments of viral proteins were retrieved as the bases for epitope screening. The selection of epitopes was then carried out with criteria such as antigenicity, immunogenicity, and binding affinity with MHC molecules, while the exclusion criteria were according to their allergenicity, toxicity, and potential for antibody-dependent enhancement. We then constructed a core antigen with the selected epitopes and linked the outcomes with distinct adjuvant proteins, resulting in three candidate vaccines: PSDV-1, PSDV-2, and PSDV-3. Among these, PSDV-2 was selected for further validation due to its superior physicochemical and structural properties. Extensive simulations demonstrated that PSDV-2 exhibited strong binding to pattern recognition receptors, high stability, and robust immune induction, confirming its potential as a high-quality vaccine candidate. For its recombinant expression, a plasmid was subsequently designed. Our new vaccine design offers a promising additional option for Dengue virus protection. Further experimental validations will be conducted to confirm its protective efficacy and safety. Full article

French Guiana lacks a dedicated model for developing an early warning system tailored to its entomological contexts. We employed a spatiotemporal modeling approach to predict the risk of Aedes aegypti larvae presence in local households in French Guiana. The model integrated field data on larvae, environmental data obtained from very high-spatial-resolution Pleiades imagery, and meteorological data collected from September 2011 to February 2013 in an urban area of French Guiana. The identified environmental and meteorological factors were used to generate dynamic maps with high spatial and temporal resolution. The study collected larval data from 261 different surveyed houses, with each house being surveyed between one and three times. Of the observations, 41% were positive for the presence of Aedes aegypti larvae. We modeled the Aedes larvae risk within a radius of 50 to 200 m around houses using six explanatory variables and extrapolated the findings to other urban municipalities during the 2020 dengue epidemic in French Guiana. This study highlights the potential of spatiotemporal modeling approaches to predict and monitor the evolution of vector-borne disease transmission risk, representing a major opportunity to monitor the evolution of vector risk and provide valuable information for public health authorities. Full article

Among the main arboviruses affecting public health in tropical regions are dengue, zika, and chikungunya, transmitted mainly by mosquitoes of the Aedes genus, especially Aedes aegypti. In recent years, outbreaks have posed major challenges to global health, highlighting the need for integrated and innovative strategies for their control and prevention. Prevention strategies include the elimination of vectors and avoiding mosquito bites; this can be achieved through the use of bioinsecticides and repellents based on plant phytochemicals, as they offer sustainable, ecological, and low-cost alternatives. Mexico has a variety of plants from which both extracts and essential oils have been obtained which have demonstrated significant efficacy in repelling and/or killing insect vectors. This review examines the current knowledge on plant species found in Mexico which are promising options concerning synthetic compounds in terms of their repellent and insecticidal properties against mosquitoes of the genus Aedes and that are friendly to the environment and health. Full article

Dengue illness, caused by the dengue viruses, continues to be a major global health concern, with increasing incidence and the emergence of severe manifestations such as neurological complications. An overview of the current understanding of dengue epidemiology, clinical manifestations, and research priorities is presented here. Dengue transmission has escalated in recent years, exacerbated by factors such as vector expansion, climate change, and socioeconomic challenges. The clinical spectrum of dengue ranges from mild febrile illness to severe manifestations, including hemorrhagic fever and neurological complications. Neurological manifestations of dengue, once considered rare, are now increasingly reported, encompassing encephalitis, myelitis, and Guillain–Barré Syndrome, among others. Diagnosis primarily relies on laboratory methods such as RT/PCR, NS1 antigen detection, and serological assays. Despite advancements in understanding the dengue pathogenesis, there remains a critical need for effective vaccines, antiviral drugs, improved surveillance methods, predictive models for disease severity, and long-term studies on post-Dengue sequelae. Integrated programs and holistic approaches to dengue control are essential for mitigating its impact. Addressing these research priorities will be pivotal in combating dengue and reducing its global burden. Full article

Orthoflaviviruses, including zika (ZIKV), West Nile (WNV), and dengue (DENV) virus, induce severely debilitating infections and contribute significantly to the global disease burden, yet no clinically approved antiviral treatments exist. This review offers a comprehensive analysis of small-molecule drug development targeting orthoflaviviral infections, with a focus on NS2B-NS3 inhibition. We systematically examined clinical trials, preclinical efficacy studies, and modes of action for various viral replication inhibitors, emphasizing allosteric and orthosteric drugs inhibiting NS2B-NS3 protease with in vivo efficacy and in vitro-tested competitive NS2B-NS3 inhibitors with cellular efficacy. Our findings revealed that several compounds with in vivo preclinical efficacy failed to show clinical antiviral efficacy. NS3-NS4B inhibitors, such as JNJ-64281802 and EYU688, show promise, recently entering clinical trials, underscoring the importance of developing novel viral replication inhibitors targeting viral machinery. To date, the only NS2B-NS3 inhibitor that has undergone clinical trials is doxycycline, however, its mechanism of action and clinical efficacy as viral growth inhibitor require additional investigation. SYC-1307, an allosteric inhibitor, exhibits high in vivo efficacy, while temoporfin and methylene blue represent promising orthosteric non-competitive inhibitors. Compound 71, a competitive NS2B-NS3 inhibitor, emerges as a leading preclinical candidate due to its high cellular antiviral efficacy, minimal cytotoxicity, and favorable in vitro pharmacokinetic parameters. Challenges remain in developing competitive NS2B-NS3 inhibitors, including appropriate biochemical inhibition assays as well as the selectivity and conformational flexibility of the protease, complicating effective antiviral treatment design. Full article

Wolbachia symbionts introduced into Aedes mosquitoes provide a highly effective dengue virus transmission control strategy, increasingly utilised in many countries in an attempt to reduce disease burden. Whilst highly effective against dengue and other positive-sense RNA viruses, it remains unclear how effective Wolbachia is against negative-sense RNA viruses. Therefore, the effect of Wolbachia on Bunyamwera virus (BUNV) infection in Aedes aegypti was investigated using wMel and wAlbB, two strains currently used in Wolbachia releases for dengue control, as well as wAu, a strain that typically persists at a high density and is an extremely efficient blocker of positive-sense viruses. Wolbachia was found to reduce BUNV infection in vitro but not in vivo. Instead, BUNV caused significant impacts on density of all three Wolbachia strains following infection of Ae. aegypti mosquitoes. The ability of Wolbachia to successfully persist within the mosquito and block virus transmission is partially dependent on its intracellular density. However, reduction in Wolbachia density was not observed in offspring of infected mothers. This could be due in part to a lack of transovarial transmission of BUNV observed. The results highlight the importance of understanding the complex interactions between multiple arboviruses, mosquitoes and Wolbachia in natural environments, the impact this can have on maintaining protection against diseases, and the necessity for monitoring Wolbachia prevalence at release sites. Full article

We determined the dengue virus (DENV) serotypes and genotypes in archived serum samples that were collected during the 2014–2016 and 2021 dengue outbreaks in Dire Dawa City and the Somali region in Ethiopia. DENV serotype 1 (DENV-1) was predominant followed by DENV serotype 2 (DENV-2). Thirteen of the DENV-1 strains were assigned to Genotype-I, while the remaining two were found to be Genotype-III. All three DENV-2 strains were assigned the Cosmopolitan Genotype. The DENV strains responsible for the outbreaks are genetically closely related to the DENV strains that circulated in neighboring and Asian countries. The findings also showed continued local transmission of a monophyletic lineage and a co-circulation of DENV-1 and DENV-2 during the outbreaks. There is a need to strengthen DENV genomic surveillance capacity for the early detection of circulating serotypes, and prevent devastating consequences of future outbreaks due to the co-circulation of different serotypes. Full article

Aedes mosquito-borne diseases remain a significant global health threat, necessitating effective control strategies. This study introduces monoterpenes-based nanohydrogels for potential use as repellents against Aedes aegypti, the primary dengue vector worldwide. We formulated hydrogels using cymene- and myrcene-based nanoemulsions with different polymers: chitosan, carboxymethylcellulose (CMC), and carbopol^®. Our evaluations of rheological, texture, and bioadhesive properties identified CMC hydrogel as the most promising gelling agent for topical application, exhibiting sustained monoterpene release over 12 h with low skin permeation and high retention in the stratum corneum. Myrcene-loaded CMC hydrogel achieved a 57% feeding deterrence compared to 47% with cymene hydrogel in the mosquito membrane-feeding model. Molecular docking studies revealed interactions between myrcene and an essential amino acid (Ile116) in the Ae. aegypti odorant-binding protein 22 (AeOBP22), corroborating its higher repellent efficacy. These findings suggest that myrcene-loaded CMC hydrogels offer a promising, minimally invasive strategy for personal protection against Ae. aegypti and warrant further investigation to optimize monoterpene concentrations for vector control. Full article

The main focus in this manuscript is to find a numerical solution of a dengue fever disease model by using the Fibonacci wavelet method. The operational matrix of integration has been obtained using Fibonacci wavelets. The proposed method is called Fibonacci wavelet collocation method (FWCM). This biological model has been transformed into a system of nonlinear algebraic equations by using the Fibonacci wavelet collocation scheme. Afterward, this system has been solved by using the Newton–Raphson method. Finally, we provide evidence that our results are better than those obtained by various current approaches, both numerically and graphically, demonstrating the method’s accuracy and efficiency. Full article