Search Results (67)

West Nile virus (WNV) remains the most frequently reported locally acquired arboviral infection in the United States, yet many small and mid-sized mosquito abatement districts lack the diagnostic capacity and integrated data systems needed for rapid detection and response. The Canyon County Mosquito Abatement District (CCMAD) in southwestern Idaho undertook a multi-year capacity-building effort to expand arbovirus surveillance, standardize mosquito identification and pooling procedures, and implement triplex RT-qPCR testing for WNV, Western equine encephalitis virus (WEEV), and St. Louis encephalitis virus (SLEV). Historical trapping datasets (2021–2025) were consolidated, geospatially harmonized, and grouped into biologically meaningful sampling units to enable multi-year spatial comparisons. Surveillance revealed recurrent WNV activity annually, with peak transmission occurring between epidemiological weeks 31 and 37. The highest WNV activity occurred in 2023 and 2025, with 192 and 92 positive pools, respectively, while no WEEV or SLEV detections were observed. Enhanced laboratory capacity reduced sample-processing times, decreased the reliance on external confirmatory testing, lowered per-pool testing costs, and enabled same-day reporting to operational staff. In 2025, routine gravid trap surveillance detected a single Aedes aegypti, which was identified morphologically and subsequently confirmed by DNA barcoding, prompting targeted follow-up trapping. CCMAD’s integrated approach provides a scalable model for strengthening local surveillance and response capabilities in resource-limited settings. Full article

The northward expansion of Dirofilaria spp. is a current medical and veterinary concern. However, it is unclear how far north the parasite has spread in Western Siberia and what species of mosquito can carry and transmit it. This study examined Dirofilaria spp. infection in Aedes mosquitoes in the taiga zone of the Irtysh Basin. The mosquito species were identified based on morphology, and Dirofilaria spp. were identified using PCR. Of the 13 habitats surveyed, 24 of 2205 mosquito samples were infected with D. repens and 1 with Dirofilaria sp. The highest infection rate (~7.6) was recorded in Tobolsk, Tyumen region, at 58.4° N. Mosquito infection was recorded as far north as 61° N in Khanty-Mansiysk. The presence of the infective L3 stage of the parasite was recorded up to 60° N in Bobrovsky. Nine species of mosquitoes were found to be infected with D. repens: Aedes rossicus, Aedes behningi, Aedes cantans, Aedes communis, Aedes cyprius, Aedes euedes, Aedes excrucians, Aedes flavescens, and Aedes sticticus. Two of these species, Ae. behningi and Ae. communis, were competent vectors of the parasite. Thus, D. repens has successfully adapted to the Aedes mosquito in the taiga zone of Siberia. Full article

Dengue virus (DENV) and Zika virus (ZIKV) are flaviviruses transmitted by Aedes spp. mosquitoes, causing a spectrum of symptoms ranging from mild fevers and joint pain to severe damage to vital organs, including the kidneys, brain, and liver. Unfortunately, there are currently no specific treatments for these viruses. The NS2B/NS3 serine protease has been recognized as a crucial therapeutic target due to its pivotal role in viral replication. Herein, several molecular modeling techniques were employed to search for novel allosteric inhibitors against DENV and ZIKV NS2B/NS3 proteases from a set of 545 in-house compounds. Virtual screening based on molecular docking and MM/GBSA-based free energy calculations indicated that, among 545 derivatives, four compounds demonstrated high binding affinity against both targets, including two sulfonamide-vinyl sulfone hybrids (cpd48_e and cpd50_e), one sulfonamide-chalcone analog (cpd48), and one berberine-cinnamic acid derivative (DN071_f). Their molecular complexation was driven mainly by van der Waals forces rather than electrostatic attraction. Several residues at the enzyme allosteric site, particularly K74, L149, and N152 (DENV) and L76, I123, N152, and V155 (ZIKV), were identified as binding hotspots for the screened compounds. Drug-likeness predictions based on Lipinski’s rule of five further supported their potential as drug candidates. Overall, these findings provide valuable insights for the future design and development of novel antiviral drugs targeting the DENV and ZIKV NS2B/NS3 proteases. Full article

West Nile virus (WNV) is a mosquito-borne pathogen of the Flaviviridae family that poses recurring public health threats in Tunisia, where Culex pipiens is recognized as the primary vector. Identification of circulating strains in different mosquito species is essential for targeted prevention and control. Between November 2021 and October 2022, mosquitoes were collected at four high-risk sites, and human samples were obtained through the national meningitis surveillance program. Human serum, cerebrospinal fluid (CSF), and urine samples were tested for WNV-specific IgM and IgG antibodies using ELISA, and molecular diagnosis was performed using Real-time RT-PCR (RRT-PCR). Positive samples underwent sequencing for phylogenetic characterization. Serological investigation on human serum revealed the presence of IgM and/or IgG antibodies reactive to WNV antigens, which may indicate exposure to WNV or related flaviviruses. RNA of WNV was detected in 21 mosquito pools (10.19%) belonging to Culex pipiens, Cx. perexiguus, Aedes caspius, and Ae. detritus, as well as in three human cases. Phylogenetic analysis of positive human and mosquito samples showed that all detected WNV strains belonged to sublineage 1a. The concurrent detection of WNV in vectors and humans confirms active circulation in Tunisia and underscores the role of Culex spp. Mosquitoes in transmission. Sustained multidisciplinary surveillance integrating entomological and clinical data is critical for early detection, guiding control measures, and preventing future outbreaks in humans and animals. Full article

In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease incidence and insecticide resistance (IR) call for a critical appraisal of historical and current control practices. This literature review compiles secondary data produced from 1901 to 2024 obtained from Medline/PubMed, Google Scholar, and governmental notes and reports. Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, carbamates, pyrethroids, insect growth regulators, microbial larvicides (Bti and Lsp), spinosad, and recently formulations with dual active-ingredient. Ae. aegypti showed widespread resistance to temephos and pyrethroids, decreased susceptibility to pyriproxyfen, and no documented Bti resistance. Anopheles spp. exhibited low to moderate resistance to pyrethroids. Cx. quinquefasciatus resistance is likely influenced by collateral exposure from Aedes control and domestic use. Regarding triatomines and phlebotomines, there was a predominant reliance on pyrethroids; most studies indicate their susceptibility to these compounds. In short, Brazil’s century-long, insecticide-centric strategy has delivered episodic gains but fostered Aedes aegypti resistance. For other species, for which there is no dedicated program for a long period, data on resistance are scarce or nonexistent. Sustainable progress requires strengthened, nationwide IR surveillance and entomological mapping to coordinate cross-program actions. Full article

While a great deal of research has been conducted to identify the biotic mechanisms influencing the co-occurrence of aquatic Ae. aegypti and Ae. albopictus mosquitoes, including inter-specific larval competition and mating interference, few studies have been completed to investigate their oviposition behaviors under co-occurrence scenarios. Herein, we performed three experiments to understand the influence of conspecific and heterospecific L4-larvae presence in oviposition by antagonist Aedes spp. mosquitoes. We compared egg counts of Ae. aegypti and Ae. albopictus in cups with water and conspecific or heterospecific larvae (either present or removed), or no larvae as control. In the first experiment, we used small cages; in the second experiment, we used larger cages increasing the number of treatment replicates per cage; and in the third experiment, we removed larvae before allowing gravid females to oviposit. In experiments 1 and 2, Ae. aegypti laid more eggs in conspecific cups, while Ae. albopictus distributed eggs evenly between conspecific and heterospecific cups, and both species laid fewer eggs in controls. In these experiments, more eggs were laid during the first 24 h. In experiment 3, both species laid more eggs in conspecific larvae-conditioned water as compared to controls in the first 24 h; however, in Ae. Aegypti, this inclination was lost with time. Our results suggest that co-occurrence of Ae. aegypti and Ae. albopictus may be explained by Ae. aegypti’s ability to avoid oviposition in habitats colonized by heterospecific L4-larvae. Yet chemical cues in conspecific L4-larvae-conditioned water were insufficient to replicate this behavior, and therefore, additional cues may be involved. Full article

Aedes (Stegomyia) albopictus (Skuse), a mosquito vector with increasing capacity to transmit human arboviral infections worldwide, naturally harbors the intracellular bacterium Wolbachia spp. This relationship has been observed in native mosquito populations of Ae. albopictus around the world and, more recently, in Mérida, Yucatán, México (abbreviated hereafter as MID). This study provides additional evidence confirming the presence of Wolbachia A (wAlbA) and B (wAlbB) strains in field-collected Ae. albopictus of Mérida, based on wsp gene DNA sequencing analyses of 14 positive PCR samples. Maximum likelihood (ML) analyses of the wsp gene showed high nucleotide sequence homology between Wolbachia from Merida and the globally reported strains A and B, suggesting that these two Wolbachia strains have remained stable in Ae. albopictus over time, regardless of the geographical area. To the best of our knowledge, this is the first report of Wolbachia gene sequencing in native populations of Ae. albopictus in Yucatán, Mexico. Currently many Aedes mosquitoes (e.g., Ae. aegypti) harboring intracellular Wolbachia B bacteria are being released as part of arbovirus and mosquito control programs in Yucatan and globally. Understanding the presence and stability of Wolbachia strains across different Aedes host backgrounds is crucial to ensuring the long-term effectiveness of biological interventions aimed at controlling mosquito populations and arbovirus transmission in endemic areas. Full article

The chemical composition of leaf essential oil of the harmful invasive species Chromolaena odorata collected in Vietnam was analyzed by GC/MS and chiral GC. All three essential oil samples (O1, O2 and O3) in this study fell into chemotype I characterized by α-pinene/geigerene/germacrene D/(E)-β-caryophyllene from a total of six different chemotypes. Chemotype I demonstrated larvicidal effects against Aedes aegypti (Linnaeus, 1762), Aedes albopictus Aedes albopictus (Skuse, 1894), Culex fuscocephala (Theobald, 1907) and Culex quinquefasciatus (Say, 1823), with 24 h LC₅₀ values ranging from 11.73 to 69.87 µg/mL. In contrast, its microemulsion formulation exhibited enhanced toxicity, yielding 24 h LC₅₀ values between 11.16 and 32.43 µg/mL. This chemotype also showed repellent efficacy against Ae. aegypti, with protection times ranging from 70.75 to 122.7 min. Fumigant toxicity was observed against Aedes aegypti, with LC₅₀ values of 40.27% at 0.5 h and 0.34% at 24 h. Molluscicidal activity was recorded with 48 h LC₅₀ values between 3.82 and 54.38 µg/mL against Indoplanorbis exustus (Deshayes, 1833), Pomacea canaliculate (Lamarck, 1822), Physa acuta (Draparnaud, 1805). Additionally, the chemotype exhibited acetylcholinesterase inhibitory activity, with an IC₅₀ value of 70.85 µg/mL. Antimicrobial potential was also demonstrated, with MIC values ranging from 2.0 to 128.0 µg/mL against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella enterica, and Candida albicans. The C. odorata essential oil can be considered as a potential bioresource for human health protection strategies. Full article

Between 2016 and 2018, the state of Minas Gerais, Brazil, experienced its most significant yellow fever (YF) outbreak in 80 years. Yellow fever virus (YFV) circulation persisted afterward, with continued non-human primate (NHP) epizootics and, recently, human cases. In June 2024, YFV RNA was detected in a dead marmoset (Callithrix penicillata) in an urban square in Belo Horizonte (BH), prompting a field investigation in an adjacent park to assess infection in potential mosquito vectors and NHPs. A total of 250 mosquitoes representing nine species were collected at ground and canopy level, of which Aedes fluviatilis and Aedes scapularis comprised 78.8% of the specimens. Haemagogus spp. and Sabethes spp. mosquitoes were not collected, possibly due to the short sampling window during the dry season. No active YFV infection was detected in any of the mosquito pools tested. Eight marmosets (Callithrix penicillata) were captured and tested for arboviral infections. Five out of eight sera, representing both adult and juvenile (less than 17 months old) animals, tested positive for anti-YFV IgM. Interestingly, two adults recaptured in later expeditions revealed seroconversion. One was IgM-positive in July 2024 but negative by September 2024, consistent with the expected decline in IgM levels. The other, initially IgM-negative (as of July 2024), tested positive in April 2025, indicating recent exposure to YFV. These findings provide evidence for the ongoing, low-level circulation of YFV among urban NHPs, posing a continued risk of viral spillover to humans. Moreover, these results highlight the importance of active surveillance in detecting recent infections that would likely be missed by passive monitoring. This integrated approach enhances our understanding of local YF epidemiology and supports early, evidence-based public health interventions to prevent future human outbreaks. Full article

Since there are no available vaccines against some arboviruses, vector control is the most effective way to reduce their incidence. In this context, mechanical control is one of the most cost-effective ways to suppress Aedes populations, but it requires knowledge about vector breeding ecology in varied landscapes and climates. Here we investigated the infestation levels and container types used as larval habitats by Aedes aegypti and Aedes albopictus in an urban gradient of Vassouras, a countryside city in Rio de Janeiro. Larval surveys were conducted bimonthly from January 2017 to December 2018. Infestation was measured through the House (HI) and Breteau indexes (BI). Container types found with Aedes spp. immatures were correlated with temperature and rainfall and were compared between urbanization zones. The distribution of positive containers was mapped. The HI for Ae. aegypti increased during rainy seasons, but the HI and BI were always <1% for both mosquito vectors. More reservoirs were found harboring Ae. albopictus than Ae. aegypti, but in general their relative distribution into types was similar between species. On the other hand, the amount and distribution of containers into types varied across urbanization zones. Finally, the spatial distribution of larval habitats was similar between species, as well as often constant between seasons and study years. Full article

Arboviruses, including but not limited to dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV), pose a significant global threat to human health. The transmission of DENV, ZIKV, and CHIKV is facilitated by mosquitoes belonging to the genus Aedes, which are prevalent in both urban and rural regions of Vietnam. In 2023 an investigation into the population of mosquitoes was conducted in a number of provinces located within the central region of Vietnam. A total of 12,546 mosquitoes were collected during the study. The mosquitoes collected comprised the genera Culex spp., Aedes spp., Anopheles spp., and Armigeres spp. The Aedes spp. mosquitoes were predominant, being collected in 908 pools. These were then examined by RT-qPCR for the detection of DENV, ZIKV, and CHIKV. DENV viral RNA was detected in 92 mosquito pools, ZIKV was detected in 1 mosquito pool, and CHIKV was not detected. The typing of samples containing DENV RNA was carried out. It is evident from the results of the typing process that three distinct types of DENV have been identified. The three main dengue virus types are DENV-1, DENV-2, and DENV-4. Full article

Yellow fever (YF) disease is a viral infection caused by Orthoflavivirus flavi (YFV). YFV is transmitted by hematophagous daytime-biting mosquitoes, predominantly Haemagogus spp. and Sabethes spp. in the sylvatic cycles, and Aedes spp. in urban cycles. In this work, we correlated vaccination coverage with the occurrence and spread of the disease throughout Brazil during the years 2016–2018. The Vale do Mucuri and Vale do Rio Doce regions in Minas Gerais state had the highest number of reported cases. Despite being considered areas with vaccine recommendation since 2008, these regions had less than 60% and 70% vaccination coverage in 2016. The outbreak of YF in Brazil has shown that surveillance for emerging diseases should be constant, especially in relation to the national immunization program. In this study, we observed that low vaccination coverage and the lack of public policies aimed at this region with low population development may have an impact on the reemergence of YF. Full article

The island of Cyprus has historically been prone to vector-borne diseases due to its location at the crossroads of three continents. The introduction of novel vectors, microorganisms, or strains in Cyprus, coupled with the global climate change and antimicrobial resistance crisis, can lead to an altered infectious disease landscape and entomological status, causing a rise in vector-borne diseases on the island. The current review provides a broad snapshot of the status of vector-borne infectious diseases and associated risks in Cyprus. Our research has uncovered a pressing issue, the risk of the spread and emergence of various infectious diseases, including West Nile virus and malaria, respectively, due to the presence of Aedes and Anopheles spp. mosquitoes on the island, while underscoring the animal reservoirs of several pathogenic microorganisms. Our research emphasizes the importance of the One Health approach and the collaboration between communities for the improvement of vector control strategies to limit the spread of vector borne diseases. Full article

CHIKV infection is transmitted by Aedes mosquitoes spp., with Ae. aegypti considered as the primary vector and Ae. Albopictus playing an important role in sustaining outbreaks in Europe. The ECSA-Indian Ocean Lineage (IOL) strain emerged in Reunion, subsequently spreading to areas such as India, the Indian Ocean, and Southeast Asia, also causing outbreaks in naive countries, including more temperate regions, which originated from infected travelers. In Italy, two authocthounous outbreaks occurred in 2007 (Emilia Romagna region) and 2017 (Lazio and Calabria regions), caused by two different ECSA-IOL strains. The phylogenetics, evolution, and phylogeography of ECSA-IOL-CHIKV strains causing the 2007 and 2017 outbreaks in Italy were investigated. The mean evolutionary rate and time-scaled phylogeny were performed through BEAST. Specific adaptive vector mutations or key signature substitutions were also investigated. The estimated mean value of the CHIKV E1 evolutionary rate was 1.313 × 10⁻³ substitution/site/year (95% HPD: 8.709 × 10⁻⁴–1.827 × 10⁻³). The 2017 CHIKV Italian sequences of the outbreak in Lazio and of the secondary outbreak in Calabria were located inside a sub-clade dating back to 2015 (95% HPD: 2014–2015), showing an origin in India. Continued genomic surveillance combined with phylogeographic analysis could be useful in public health, as a starting point for future risk assessment models and early warning. Full article

Background: Dengue, transmitted by Aedes spp. mosquitoes, poses significant public health challenges in Burkina Faso. This study investigated outbreak thresholds, utilizing historical data since 2018 to explore the climatic impacts on dengue transmission and address knowledge gaps. Methodology: This retrospective ecological study utilized historical and contemporary data from Burkina Faso’s Public Health Ministry (2018–2024) to model dengue outbreak thresholds. A combination of epidemic channel analysis, joinpoint regression, climate–disease relationship analysis, and negative binomial regression was employed to provide comprehensive insights into the factors driving dengue outbreaks. Principal Findings: The incidence of probable dengue cases remained stable, mostly below 5 cases per 100,000 people, except for a sharp surge in week 40 of 2023, peaking at 38 cases per 100,000. This surge was brief, normalizing by week 47, but coincided with a marked increase in mortality, reaching 90 deaths in week 45. Joinpoint regression identified key thresholds, an alert at 2.1 cases per 100,000 by week 41 and an intervention threshold at 19.1 cases by week 44, providing a framework for timely public health responses. Climatic factors significantly influenced dengue transmission, with higher temperatures (RR = 2.764) linked to increased incidence, while higher precipitation (RR = 0.551) was associated with lower case numbers, likely due to disrupted mosquito breeding conditions. Additionally, intermediate precipitation levels showed a complex relationship with higher incidence rates. Conclusions: This study established evidence-based epidemiological thresholds for dengue outbreak detection in Burkina Faso (2018–2024), demonstrating temperature as a primary transmission driver while precipitation showed inverse relationships. Analysis of the 2023 outbreak identified a critical five-week intervention window (weeks 40–45), providing a framework for climate-sensitive early warning systems. These findings advance the understanding of dengue dynamics in West Africa, though future research should integrate geographical and socioeconomic variables to enhance predictive modeling and outbreak preparedness. Full article