Search Results (517)

Arboviral diseases are emerging public health challenges in Burkina Faso, largely driven by the proliferation of Aedes aegypti mosquitoes in the environment. Effective surveillance of arbovirus circulation is critical to inform interventions. From August 2022 to June 2023, we implemented a comprehensive entomological surveillance platform in five sectors of Bobo-Dioulasso. Surveillance methods included oviposition traps to collect eggs, larval surveys in some concessions per sector conducted bimonthly, and adult mosquito collections using BG-Sentinel traps and Prokopack aspirators. Mosquito samples colonized by Ae. aegypti were identified morphologically, confirmed by conventional PCR, and screened by RT-PCR for dengue (DENV), chikungunya (CHIKV), yellow fever (YFV), and Zika (ZIKV) viruses. Molecular analysis detected dengue virus and yellow fever virus in mosquito pools from sector 22 and chikungunya virus in sectors 9 and 26; no Zika virus was found. This study demonstrates the successful establishment of an integrated entomological surveillance platform capable of capturing the spatial and temporal dynamics of arboviral vectors and virus circulation in Bobo-Dioulasso. The identification of active dengue and chikungunya transmission underlines the urgent need for sustained vector monitoring and targeted control strategies. Our approach provides a scalable model for arboviral disease surveillance and epidemic preparedness in West African urban settings. Full article

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus prevalent in more than 110 countries and regions, including Africa, Asia, the Americas, and Europe. It can cause acute fever, rash, and severe joint pain, and some patients may develop chronic arthritis, which significantly impairs quality of life. CHIKV infection can occasionally be fatal, with neurologic disease a particularly severe manifestation. Following its resurgence in 2005, CHIKV has emerged as a major threat to global public health. This review summarizes diagnostic techniques, advances in vaccine development, and the latest drug interventions for CHIKV. We also present an overview of the epidemiology, structure, and invasion mechanisms of epidemic hotspots in 2024–2025 and propose evidence-based strategies for effective prevention and control of CHIKV infection. Full article

Millions of healthcare workers experience percutaneous exposure to bloodborne communicable infectious disease pathogens annually, with the risk of contracting occupationally acquired infections. In this study, we aimed to assess the status of occupational safety and outbreak preparedness in Congolese nurses and laboratory technicians in Kongo central and the Katanga area, amidst multiple ongoing public health emergencies in the Democratic Republic of the Congo (DRC). This was a multicenter analytical cross-sectional study conducted in five referral hospitals located in Kongo central province and the Katanga area between 2019 and 2020 amidst Ebola, Yellow fever, Cholera and Chikungunya outbreaks. Participants were adult A0 grade nurses, A1 nurses, A2 nurses and medical laboratory technicians (N = 493). They answered a structured, self-administered questionnaire related to hospital hygiene and standard precautions for occupational infection prevention. The majority of the respondents were females (53.6%), and 30.1% of them have never participated in a training session on hospital infection prevention during their career. The proportions of those who have been immunized against hepatitis B virus (HBV) was markedly low, at 16.5%. Of the respondents, 75.3% have been using safety-engineered medical devices (SEDs), whereas 93.5% consistently disinfected medical devices after use. Moreover, 78% of the respondents used gloves during medical procedures and 92.2% wore masks consistently. A large majority of the respondents, 82.9%, have been recapping the needles after use. Regarding participation in outbreak response, 24.5% and 12.2% of the respondents were Chikungunya and Cholera epidemic responders, respectively; 1.8% have served in Ebola outbreak sites. The proportion of the respondents who sustained at least one percutaneous injury by needlestick or sharp device, blood/body fluid splash or both in the previous 12-month period was high, 89.3% (41.8% for injury, 59.2% for BBF event), and most of them (73%) reported over 11 events. Compared to laboratory technicians, nurses had higher odds for sustaining percutaneous injury and BBF events [OR = 1.38 (0.16); p < 0.01], whereas respondents with longer working experience were less likely to sustain those events [OR = 0.47 (0.11); p < 0.001]. Findings from this study suggest that Congolese nurses and laboratory technicians experience a high frequency of injury and BBF events at work, and remain at high risk for occupationally acquired infection. There is a need for periodic capacity-building training for the healthcare workforce to improve infection prevention in health settings, the provision of sufficient and appropriate PPE and SEDs, post-exposure follow-up and keeping records of occupational injuries in hospitals in Congolese healthcare settings. Full article

Dengue (DENV), Chikungunya (CHIKV), and Zika (ZIKV) are emerging arboviral threats in Bangladesh, transmitted by Aedes mosquitoes thriving in urban Dhaka. Overlapping symptoms complicate diagnosis, and Bangladesh-specific data on arboviral antibody reactivity are limited. In four hospitals of Dhaka, we conducted a cross-sectional study on 438 febrile patients aged ≥10 years, collecting samples between September and December 2023 to describe arboviral antibody reactivity and their distribution across selected demographic and environmental characteristics. Rapid diagnostic tests (RDTs) for DENV and CHIKV were performed, followed by enzyme-linked immunosorbent assay (ELISA) on RDT-reactive samples. Participants had a mean age of 30 years (±13.5); two-thirds were male, and most lived in crowded, low-income households. RDTs indicated DENV/CHIKV antibody reactivity in 40% of participants; 170 samples underwent ELISA, suggesting DENV IgG reactivity in 33.5% and IgM reactivity in 15.5%. CHIKV IgG reactivity (0.7%) was low and ZIKV IgG was reactive in 21% of total samples, and IgM was reactive in one (0.2%); most ZIKV IgG-reactive samples also showed DENV IgG reactivity, suggesting cross-reactivity. DENV IgG and IgM reactivity were associated with lower education, while ZIKV IgM reactivity was associated with older age. Awareness of Aedes mosquitoes was low, and environmental risk factors were common. This study provides cross-sectional data on serological reactivity against DENV, CHIKV, and ZIKV among febrile patients attending four hospitals of Dhaka, without aiming to establish etiologic causes of illness. ZIKV IgG antibody reactivity requires confirmatory testing to distinguish true infections from other arboviral cross-reactivity. Strengthened community-based surveys, better public awareness, and sustained vector control are critical for reducing arboviral disease risks in urbanizing settings like Dhaka, Bangladesh. Full article

The year 2025 likely marks a turning point in both the perception and the reality of mosquito-borne arboviral diseases in Europe. While chikungunya and dengue viruses have long been regarded as tropical illnesses confined to intertropical regions, West Nile virus has circulated for decades in temperate areas, including southern Europe. Nevertheless, all three mosquito-borne viruses are now increasingly established across the European continent. This evolution reflects a profound transformation of the European epidemiological landscape, where arboviral diseases are increasingly emerging as endemic and seasonal threats. This shift concerns not only the scale but also the dynamics of transmission, with the appearance of newly affected regions, an earlier onset of the transmission season, and a broader diversity of arboviruses involved. Europe is thus entering a new phase in which longer, wider, and more intense transmission of vector-borne diseases is likely to become the new norm requiring strengthened preparedness. Full article

Apart from some information on dengue virus (DENV), there is limited data on the circulation of arboviruses in Burkina Faso. The aim of this study was to investigate antibody prevalence against six arboviruses in four regions of the country to document previous virus exposure. Serum samples collected between August 2018 and December 2022 from people infected with viral hepatitis B and C in Bobo-Dioulasso were used to detect IgG antibodies against DENV, Chikungunya virus (CHIKV), Zika virus (ZIKV), Yellow fever virus (YFV), Rift Valley fever virus (RVFV) and Crimean-Congo hemorrhagic fever virus (CCHFV) using commercial ELISA kits. A total of 1808 serum samples, accompanied by basic epidemiologic data (sex, age and residency) were included in this study. We observed an IgG antibodies seroprevalence of 75.4% for DENV, 30.8% for CHIKV, 2.9% for ZIKV, 1.2% for RVFV, 1.1% for CCHFV and 1.1% for YFV. Age, sex, and place of residence were significantly associated with seropositivity for DENV and age and sex with CHIKV seropositivity. The results suggested widespread circulation of DENV and CHIKV and possible circulation of CCHFV and RVFV in humans in Burkina Faso. The importance of strengthening arbovirus surveillance by including additional arboviruses in the diagnostic panel is emphasized. Full article

Chikungunya fever (CHIKV) has reemerged as a serious global health problem worldwide. Currently, no antiviral drugs are available for the prevention or treatment of CHIKV infection. Therefore, this study aimed to analyze the anti-CHIKV potential of the alga Spirulina maxima. Extracts were obtained by maceration using solvents of different polarities (hexane, dichloromethane, and methanol). The cytotoxic activity of the extracts was evaluated using the MTT assay, which demonstrated that none of the extracts had a cytotoxic effect on VERO and BJ cell lines. The anti-CHIKV effect was evaluated using a plate assay with VERO, HepG2, and BJ cell lines. The results showed that the methanol extract had the best anti-CHIKV effect, completely inhibiting viral replication at a concentration of 15 µg/mL in all three cell lines. Furthermore, the addition time assay suggested that the mechanism of action is related to the inhibition of some processes at the beginning of the infection, such as the entry or early replication of the virus. In conclusion, SP contains molecules that could provide a basis for future research on the development of new drug therapies against CHIKV. Full article

Chikungunya virus (CHIKV) poses a significant public health threat, and its continuous evolution necessitates high-resolution genomic surveillance. Current methods lack the speed and resolution to efficiently discriminate sub-lineages. To address this, we developed CHIKVGenotyper, an interpretable machine learning framework for high-resolution CHIKV lineage classification. This study leveraged a comprehensive dataset of 6886 CHIKV genome sequences, from which a high-quality set of 3014 sequences was established for model development. A hierarchical assignment pipeline that integrated a probability-based sequence matching model, machine learning refinement, and phylogenetic validation was developed to assign high-confidence labels across eight CHIKV lineages, thereby constructing a reliable dataset for subsequent analysis. Multiple machine learning models were trained and evaluated, with the optimal Random Forest model achieving near-perfect accuracy (F1-score: 99.53%) on high-coverage whole-genome test data and maintaining robust performance (F1-score: 96.50%) on an independent low-coverage set. The E2 glycoprotein alone yielded comparable accuracy (F1-score: 99.52%), highlighting its discriminative power. SHapley Additive exPlanations (SHAP) analysis identified key lineage-defining amino acid mutations, such as E1-K211E and E2-V264A, for the Indian Ocean Lineage, which were corroborated by established biological knowledge. This work provides an accurate, scalable, and interpretable tool for CHIKV molecular epidemiology, offering insights into viral evolution and aiding outbreak response. Full article

Dengue fever has become a major global public health challenge due to its rapidly in-creasing incidence. Rapid on-site detection of dengue virus (DENV) is critical for early diagnosis, timely patient isolation, and outbreak control. In this study, dengue virus serotype 2 (DENV-2), the predominant strain circulating in tropical and subtropical regions, was selected as the target pathogen. We established a one-tube rapid detection assay that integrates the HUDSON nucleic acid extraction-free protocol, reverse transcription recombinase-aided amplification (RT-RAA), and CRISPR/Cas12a-mediated trans cleavage activity. The method achieved a detection limit of 1 × 10² copies/μL for simulated infected samples and exhibited no cross-reactivity with other DENV serotypes (DENV-1, DENV-3, DENV-4) or with other arboviruses, including Zika, Japanese encephalitis, yellow fever, and chikungunya viruses. The assay demonstrated high sensitivity and specificity across various sample types, including mosquitoes, rodents, blood, and cultured cells, with results consistent with quantitative PCR (qPCR). Requiring only basic equipment such as a water bath, the system enables on-site detection of DENV-2 within 1 h. This simple, cost-effective, and reliable assay provides a practical tool for field-based DENV-2 surveillance and supports effective public health responses in resource-limited settings. Full article

Alphaviruses pose a growing global health threat, with Chikungunya virus (CHIKV) epidemics ongoing. Although several CHIKV vaccine candidates have progressed to late-stage clinical evaluation, none have yet achieved licensure or widespread availability. The CHIKV nonstructural proteins nsP2 and nsP4 encode essential enzymatic activities that represent key targets for antiviral development, yet the biochemical basis of nsP4 RNA-dependent RNA polymerase (RdRp) activity remains poorly understood. Here, we identify a minimal, functional precursor form of nsP4 derived from the nsP3–nsP4 polyprotein (P34) that is active in a cell-based RNA replicon system. Using synthetic, capped mRNAs, we show that cleavage of P34 by the nsP2 protease is required for robust reporter expression, and that a truncated form retaining only the C-terminal 50 residues of nsP3 (CT50-P34) supports near-wild-type replication. Unexpectedly, ubiquitin–nsP4 fusions failed to substitute for P34, likely reflecting the transient expression supported by our RNA-based system. We propose that precursor forms of nsP4 interact with the nsP1 dodecamer at the site of genome replication, where cleavage activates the RdRp and localization within the nsP1 dodecamer maintains nsP4 in its active conformation. Dissociation from the nsP1 dodecamer triggers a conformational switch to an inactive state. Together, these findings establish a tractable framework for interrogation of the assembly, activation, and regulation of the alphavirus polymerase. Full article

Background: Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, remains a leading cause of viral encephalitis. Current management is largely supportive, with no specific antivirals. This study evaluated the antiviral efficacy and mechanism of action of CC-90009 against JEV in vitro and in vivo. Methods: Five targeted protein degraders (TPDs) were screened for anti-JEV activity in the human neuroblastoma cell line SH-SY5Y. Time-of-addition, binding, and endocytosis assays were used to delineate the phase of action of CC-90009, a cereblon (CRBN) E3 ligase modulator (CELMoD) and molecular glue degrader. Small interfering RNA knockdown and co-immunoprecipitation (Co-IP) confirmed targets essential for its antiviral effects. The broad-spectrum activity of CC-90009 against other mosquito-borne viruses was also evaluated. In vivo efficacy was tested in a murine JEV model. Results: Of the five TPDs tested, only CC-90009 significantly inhibited JEV infection in SH-SY5Y cells, acting during both viral entry and post-entry phases without reducing adsorbed or internalised virions. CC-90009 reduced JEV RNA and non-structural protein accumulation. Knockdown of G1-to-S phase transition 1 (GSPT1), a key target of CC-90009, suppressed JEV infection and translation; Co-IP confirmed GSPT1 interaction with JEV non-structural protein 5 (NS5). CC-90009 disrupted JEV translation and replication by inducing proteasomal degradation of the GSPT1/NS5 complex, further demonstrating its broad-spectrum antiviral activity through the effective inhibition of West Nile virus and chikungunya virus. In vivo, it protected mice from JEV-induced mortality, reducing viral load, antigen levels, and brain pathology. Conclusions: CC-90009 exerts potent anti-JEV activity both in vitro and in vivo by inducing proteasomal degradation of the GSPT1/NS5 complex, thereby disrupting viral translation and replication. This targeted protein degradation strategy represents a novel host-directed antiviral approach with promising therapeutic potential against mosquito-borne viral encephalitis. Full article

Aedes aegypti is the primary urban vector for several important arboviruses, including dengue, chikungunya, yellow fever, and Zika viruses. Traditional dengue virus (DENV) surveillance relies on passive reporting of human cases, which often underestimates transmission due to asymptomatic or unreported infections. This study evaluated the utility of monitoring DENV in Ae. aegypti mosquitoes to improve detection of local dengue transmission and inform vector control strategies during the 2024 dengue epidemic in Puerto Rico. Mosquito surveillance was conducted in 15 neighborhoods within the San Juan metropolitan area where confirmed dengue cases had been recently reported. Adult female Ae. aegypti were collected weekly using Autocidal Gravid Ovitraps (AGO traps) placed within a 200 m radius of index cases. Pools of 1–20 mosquitoes were tested for DENV RNA and serotype using RT-PCR. Surveillance continued for up to 91 days in study areas, depending on virus detection. A total of 29,354 female Ae. aegypti were collected, of which 29,211 females were pooled (1–20 specimens per pool) into 3878 pools and analyzed. DENV was detected in 49 pools across 11 neighborhoods, with serotypes DENV-1, DENV-2, and DENV-3 identified. Multiple serotypes were sometimes detected in mosquitoes from the same neighborhood. Minimum infection rates and vector indices were higher during the epidemic than in previous inter-epidemic periods, and mosquito densities exceeded thresholds considered protective against outbreaks. Entomo-virological surveillance detected a greater variety and evenness of serotypes than passive human surveillance. These findings suggest that entomo-virological surveillance can complement passive case surveillance, providing a more comprehensive detection of DENV circulation. Integrating mosquito-based and human surveillance can improve outbreak detection, guide vector control, and aid in reducing dengue burden in affected communities. Full article

Background/Objectives: As of April 2025, La Réunion is facing a second major chikungunya virus (CHIKV) outbreak, following the 2005–2006 epidemic that infected nearly one-third of the population. IXCHIQ^®, a live-attenuated, single-dose vaccine, offers an opportunity for targeted immunization to complement vector control efforts. Using surveillance data up to 23 February 2025 (week 7), we estimated the potential scale of the 2024–2025 chikungunya outbreak in La Réunion and how much of the burden could have been averted by an emergency vaccination campaign at different detection thresholds. Methods: A stochastic SEIR–SEI host–vector model was calibrated to weekly case counts (weeks 46/2024–7/2025). We projected the epidemic under three vaccination-trigger scenarios (≥100, ≥3000, ≥40,000 detected cases) and two incremental vector-control assumptions (10% and 20% reductions in biting rate). Several mosquito-related parameters—extrinsic incubation period, offspring number, and mortality rate—were temperature-dependent, based on daily temperatures in La Réunion. Vaccination was applied homogeneously, using a 14.5% coverage to reflect the proportion of the population targeted in the initial public health recommendation. Results: Our findings indicate that without vaccination, up to 27.5% of the population could become infected. If vaccination would begin after 100 detected cases, 75% of infections could be prevented. Delaying until 3000 or 40,000 cases reduced effectiveness to 41% and 11%, respectively. Conclusions: Our results show that timely emergency vaccination can substantially reduce outbreak size. This underscores the importance of preparedness and rapid response by public health authorities in high-risk regions. Full article

Arthropod-borne viruses (arboviruses) are an increasingly significant threat to public health in tropical regions. In this study, we investigated the seroprevalence of various arboviruses in two species of sloth (Choloepus hoffmanni and Bradypus variegatus) in rural and peri-urban areas of Western Panama province. Between 2013 and 2018, blood samples from 60 sloths were tested for neutralizing antibodies against ten arboviruses. Significant variation in seroprevalence of different arboviruses was observed: 6.7% of sloths were seropositive for Madariaga virus, 6.7% for Venezuelan equine encephalitis virus, and 4.8% for Oropouche virus, while none were seropositive for dengue type 2, Zika, chikungunya, Una, Mayaro, or Punta Toro viruses. Notably, two Changuinola virus (CGLV) strains, which were previously isolated from Panamanian sloths in the 1970s, showed high seroprevalence: Pansloth 149 (23.3%) and D50 (53.3%). Given the high seroprevalence detected in our study and the lack of genomic characterization of the historical Pansloth 149 isolate, we performed next-generation sequencing of its complete genome using Illumina technology to understand its genetic diversity and evolutionary relationship with other CGLV strains. Full article

Multiplexed detection of arboviruses using a 4 × 4 Si-based electrolyte-gated transistor (EGT) array functionalized with specific aptamers has been investigated. The Si-based EGTs were fabricated using conventional Si microfabrication processes. The EGTs showed excellent intrinsic electrical characteristics, including a low threshold voltage of 0.8 V, a sub-threshold swing of 75 mV/dec, and a gate leakage of <10 pA, ensuring uniform device performance with low device-to-device variation. Aptamers specific to the yellow fever virus nonstructural protein 1 (YF), dengue virus nonstructural protein 1 (DN), and chikungunya virus envelope protein 2 (CHK) were functionalized on EGT arrays to evaluate individual and multiplexed detection. In individual-target detections, concentration-dependent negative shifts in threshold voltage were observed, and relevant limits of detection (LOD) as low as 38.6 pg/mL, 95.2 pg/mL, and 1.6 ng/mL were extracted for YF, DN, and CHK, respectively. In multiplexed detections, sensitivities decreased and variations increased relative to the individual responses, resulting in higher LODs. The extracted LODs were 0.2 ng/mL, 0.6 ng/mL, and 2.8 ng/mL for YF, DN, and CHK, respectively, which are lower than those reported for other methods. These results suggest that Si-based EGT arrays are promising as a scalable, low-cost, and highly sensitive biosensing platform for multiplexed arbovirus detection and point-of-care diagnostics. Full article