Search Results (242)

Background and Objectives: Climate change is modifying the ecological and climatic conditions that influence the distribution and activity of arthropod vectors. Rising temperatures and prolonged warm seasons have favored the establishment of Aedes albopictus in Mediterranean regions, increasing the risk of autochthonous Dengue transmission. Therefore, this study describes the evolution of Dengue surveillance in Sardinia between 2018 and 2024, integrating human and entomological data to assess trends, system performance, and implications for prevention and control. Materials and Methods: Data on human cases were retrieved from national notification systems (namely PREMAL, arbo.iss.it) and the New Health Information System. Entomological surveillance data were obtained from the Experimental Zooprophylactic Institute of Sardinia. Mosquitoes were collected using BG-Sentinel^® traps and ovitraps, covering major cities and points of entry. Descriptive analyses were conducted for both datasets. Results: Sixteen Dengue cases were reported during the study period, all imported and laboratory-confirmed in 81% of cases. Most patients were adults (mean age 38 years), and 77% required hospitalization. The most frequent travel origins were Southeast Asia, Africa, and Latin America. No autochthonous cases were identified. Entomological surveillance showed a progressive increase in Aedes albopictus captures from 2020 onwards, with seasonal peaks between September and October. Despite intensified sampling and expanded geographic coverage, no mosquito pools tested positive for the Dengue virus. Conclusions: Although no locally acquired Dengue infections have been detected, the widespread and increasing presence of Aedes albopictus indicates that Sardinia meets the ecological prerequisites for possible autochthonous transmission. Strengthening the timeliness and completeness of human surveillance, improving clinicians’ awareness of reporting requirements, promoting vaccination for travelers, and maintaining continuous entomological monitoring are essential to prevent and promptly manage future outbreaks. Full article

Zika virus (ZIKV) was first identified in Africa in the mid-20th century and circulated for decades with limited and often unnoticed human cases. This situation changed with the emergence of the Asian lineage, responsible for large outbreaks in the Pacific and the Americas and for severe complications such as Guillain–Barré syndrome and Congenital Zika Syndrome (CZS). In contrast, the African lineage, although frequently more efficient in replication, cytopathogenicity, and mosquito transmission in experimental systems, has not been linked to comparable epidemics or congenital disease clusters. This review summarizes current knowledge on the differences between African and Asian lineages at the molecular, cellular, and epidemiological levels. It highlights how genetic variation interacts with host immunity, ecological factors, and human activity to shape epidemic potential. Understanding these interactions is essential for anticipating future outbreaks and for improving strategies to mitigate the impact of emerging arboviruses. Full article

West Nile Virus (WNV), a mosquito-borne flavivirus first identified in Uganda in 1937, has emerged over the past quarter century as a major global public health threat. Since its introduction into North America in 1999, WNV has become the leading cause of arboviral neuroinvasive disease, with recurrent outbreaks continuing across Europe, Africa, and the Americas. This review provides a comprehensive overview of the microbiology, epidemiology, and clinical impact of WNV. We discuss the molecular biology of the virus, highlighting its genomic organization, replication strategies, and the structural and non-structural proteins that underpin viral pathogenesis and immune evasion. The complex enzootic transmission cycle, involving Culex mosquitoes and diverse avian reservoir hosts, is examined alongside ecological and climatic determinants of viral amplification and spillover into humans and equines. The clinical spectrum of WNV infection is outlined, ranging from asymptomatic seroconversion to West Nile fever and life-threatening neuroinvasive disease, with particular emphasis on risk factors for severe outcomes in older and immunocompromised individuals. Current approaches to diagnosis, supportive management, and vector control are critically reviewed, while challenges in vaccine development and the absence of effective antiviral therapy are underscored. Finally, we address future research priorities, including therapeutic innovation, predictive outbreak modeling, and genomic surveillance of viral evolution. WNV exemplifies the dynamics of emerging zoonotic diseases, and its persistence underscores the necessity of a coordinated One Health approach integrating human, animal, and environmental health. Continued scientific advances and public health commitment remain essential to mitigate its enduring global impact. Full article

Scorpion venom is a rich source of diverse bioactive molecules with medicinal importance. While the venoms of many Buthidae scorpions have been extensively studied for their toxicity and therapeutic potential, Hottentotta judaicus scorpion venom (HjSV) remains poorly explored. In this study, using LC-ESI-MS, we show that HjSV has a complex composition. We find that HjSV has no significant cytotoxic effects on three human cancer cell lines, even at concentrations of up to 1000 µg/mL. However, it exerts a dose-dependent insecticidal effect against Drosophila melanogaster, a well-established genetic model organism, and two medically relevant mosquito species, Aedes albopictus and Culex pipiens. These findings highlight the venom’s selective activity and reveal a species-dependent susceptibility in insects, with mosquitoes being more sensitive than Drosophila. Furthermore, we show that at sub-lethal doses, HjSV alters D. melanogaster behavioral patterns, significantly reducing locomotor activity and increasing sleep duration. Altogether, our results provide new insights into the dual role of HjSV as both an insecticidal agent and behavioral modulator, shedding light on its ecological function in prey subduing and its potential application in pest control strategies. Full article

Oropouche virus (OROV) is an emerging arbovirus responsible for Oropouche fever, also known as sloth fever, a febrile illness that can lead to recurrent outbreaks in affected regions. Endemic to parts of South and Central America, OROV is primarily transmitted by biting midges (Culicoides paraensis), although mounting evidence implicates mosquitoes, particularly the Culex and Aedes species, as additional vectors. Recent ecological disturbances—such as deforestation, urbanization, and climate change—have driven significant shifts in vector population dynamics, contributing to the expanded geographic range and increased transmission of OROV. Notably, recent reports of OROV infections among American and European travelers to Cuba highlight the virus’s growing potential for international dissemination and underscore its significance as a global health concern. OROV is an enveloped orthobunyavirus within the Peribunyaviridae family, possessing a tripartite, single-stranded, negative-sense RNA genome composed of the S (small), M (medium), and L (large) segments. These segments encode the nucleocapsid (N) protein, glycoproteins (Gn and Gc), and RNA-dependent RNA polymerase, respectively. Despite increasing incidence and potential for global spread, no licensed vaccines or antiviral therapies currently exist, and effective diagnostic tools remain limited. Furthermore, although human-to-human transmission has not been observed, the absence of robust surveillance systems complicates timely outbreak detection and response. In this study, we present a comprehensive molecular characterization of OROV’s major structural proteins, with an emphasis on structural modeling and epitope prediction. By integrating bioinformatics approaches with available structural data, we identify key antigenic regions that could serve as targets for the development of serological diagnostics and vaccine candidates. Our findings contribute critical insights into the molecular virology of OROV and provide a foundational framework for future efforts aimed at the prevention, diagnosis, and control of this neglected tropical pathogen. These advancements are essential for mitigating the impact of OROV in endemic regions and reducing the risk of global emergence. Full article

Vector-borne diseases account for 17% of all infectious diseases. The most effective strategies for controlling these diseases have focused on decreasing the vector population, primarily through the use of insecticides. Many insecticides have no specific targets, harming pollinators and beneficial insects. Additionally, the vector populations are developing resistance, reducing the effectiveness of these strategies and increasing ecological damage. Double-strand RNA (dsRNA) is widely used in insects to study gene function by knocking down their expression. Recently, this technology has been applied to develop RNAi-based insecticides for controlling agricultural pests. These biopesticides demonstrate high specificity, as insects do not develop resistance to them, and they cause minimal ecological damage. These pesticides knock down the expression of key genes related to vital functions, development, and reproduction, which affects the insect life cycle and consequently decreases their populations. This review focuses on using RNA interference (RNAi)-based insecticides for controlling major insect vectors, including mosquitoes, kissing bugs, and ticks. We examine the advancements and challenges associated with this technology, considering the complex life cycles and feeding behavior of these insects. Furthermore, we discuss gaps in knowledge about vector biology and delivery strategies for dsRNA, which need to be addressed to enhance the application and efficiency of this emerging technology for controlling vector-borne diseases. Full article

Dichlorodiphenyltrichloroethane (DDT), used in the 20th century to combat malaria, is considered harmful to health and the environment. As an alternative, insecticides such as pyrethroids have been used, especially alphacypermethrin, which is applied in mosquito nets impregnated with long-lasting insecticide (LLIN). This study analyzed the concentrations of DDT and alphacypermethrin in soils from three municipalities in the Legal Amazon (Mazagão, Porto Velho, and Cantá) using gas chromatography. The results showed the presence of DDT and metabolites, indicating slow degradation in the region, especially in Cantá, with an average of 2.694 mg/kg of total DDT. Alphacypermethrin stands out in Porto Velho, with an average of 0.364 mg/kg, possibly due to the use of LLINs. DDT did not represent a significant ecological risk in this study, but it did present risks to human health, mainly through food intake. The incremental lifetime cancer risk (ILCR) indicated potential danger, with values of up to 2.93 × 10⁻³ for DDT and 1.17 × 10⁻¹ for alphacypermethrin. The total non-carcinogenic risk index (HI) was extreme, with a maximum value of 336.61. The pesticides evaluated did not present an ecological risk, but they do pose risks to human health, indicating irregular use of LLINs and the need for continuous monitoring. Full article

We conducted a systematic literature review, following PRISMA guidelines, to assess whether existing species distribution models for Aedes vexans reflect its known ecological requirements. This mosquito is closely associated with temporary floodwaters, making hydrological dynamics a critical factor for accurate modelling. From 28 peer-reviewed studies, we extracted 477 environmental and ecological variables and organized them into a hierarchical classification scheme with four main categories: weather, land characteristics, water characteristics, and population. We analysed patterns in variable usage and the reported importance of each variable. Our results show that flood-related variables were largely absent, despite the species’ reliance on ephemeral water bodies for reproduction. This may possibly reduce the predictive utility of existing Aedes vexans species distribution models. In contrast, urban-landscape variables were frequently used and often ranked as highly predictive, but such results were primarily found in studies that did not account for sampling bias. Full article

Mosquito community composition can differ spatially and temporally within the same wetlands. Understanding this spatiotemporal variation is crucial, particularly in wetlands of conservation importance. Here, we examine the diversity and community composition of Culicidae (Diptera) across four sites within Fetzara Lake, a large Ramsar site in Northeast Algeria. For two years, we conducted monthly field surveys across four sites (Northeast, Northwest, Southeast, and Southwest) from April 2021 to March 2023. During these surveys, we used ovitraps to sample mosquitoes and assess species richness as well as alpha and beta diversity. We identified seven mosquito species (Aedes aegypti, Ae. albopictus, Ae. geniculatus, An. labranchiae, Culex perexiguus, Cx. pipiens, and Cs. longiareolata). There was a clear dominance of Culex pipiens (Usutu and West Nile virus vector), which accounted for 74.3% of all samples, whereas Aedes aegypti was the least abundant (<1%). Species richness varied between five and six across sites. The Shannon index and beta diversity revealed significant variation in species diversity across sites and seasons, likely driven by local differences in environmental conditions. This study emphasizes the importance of local variation in environmental conditions in shaping ecological communities in space and time. Full article

As one of the key vectors for the transmission of Dengue fever, Aedes albopictus is highly ecologically adaptable. The development of environmentally compatible biological defence and control technologies has therefore become an urgent need for vector biological control worldwide. This study constructed and used double-stranded RNA (dsRNA) expression vectors targeting the cyp314a1 and cyp315a1 genes of Ae. albopictus to transform Chlamydomonas reinhardtii and Chlorella vulgaris, achieving RNA interference (RNAi)-mediated gene silencing. The efficacy of the RNAi recombinant algal strain biocide against Ae. albopictus was evaluated by administering it to Ae. albopictus larvae. The results showed that the oral administration of the cyp314a1 and cyp315a1 RNAi recombinant C. reinhardtii/C. vulgaris strains was lethal to Ae. albopictus larvae and severely affected their pupation and emergence. The recombinant algal strains triggered a burst of ROS (Reactive Oxygen Species) in the mosquitoes’ bodies, resulting in significant increases in the activities of the superoxide dismutase (SOD), peroxiredoxin (POD) and catalase (CAT), as well as significant upregulation of the mRNA levels of the CME pathway genes in larvae. In the simulated field experiment, the number of Ae. albopictus was reduced from 1000 to 0 in 16 weeks by the RNAi recombinant Chlorella, which effectively controlled the population of mosquitoes. Meanwhile, the levels of nitrogen (N), phosphorus (P), nitrate, nitrite, ammonia and COD (Chemical Oxygen Demand) in the test water decreased significantly. High-throughput sequencing analyses of 18S rDNA and 16S rDNA showed that, with the release of RNAi recombinant Chlorella into the test water, the biotic community restructuring dominated by resource competition caused by algal bloom, as well as the proliferation of anaerobic bacteria and the decline of aerobic bacteria triggered by anaerobic conditions, are the main trends in the changes in the test water. This study is an important addition to the use of RNAi recombinant microalgae as a biocide. Full article

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, poses a significant public health threat in Asia. Although Culex species are primary vectors, the role of Aedes albopictus in JEV transmission has gained attention under changing ecological conditions. This study evaluated the vector competence of Ae. albopictus for three JEV genotypes: I (GI), III (GIII), and V (GV). Laboratory-reared Ae. albopictus were orally challenged with each genotype, and infection rate (IR), dissemination rate (DR), head–thorax positivity rate (HTR, proxy for potential transmission), and transmission rate (defined as saliva positivity) were assessed at 7 and 14 days post-infection (dpi). Ae. albopictus showed marked genotype-specific differences. By 14 dpi, GV had the highest DR (100.0%) and HTR (71.7%), with viral RNA detected in 36.7% of TR. GIII showed moderate competence (76.9% DR, 39.3% HTR), but low TR (6.6%). In contrast, GI-infected mosquitoes exhibited minimal infection and negligible transmission, with viral RNA rarely detected beyond the midgut. These findings indicate that Ae. albopictus is highly competent for transmitting JEV genotype V and moderately for genotype III, but not genotype I, under laboratory conditions. This highlights its potential role in the transmission dynamics of emerging JEV genotypes and underscores the need for continued surveillance. Full article

Malaria persists as a paradigmatic model of co-evolutionary complexity, emerging from the dynamic interplay among a human host, Anopheles vectors, and Plasmodium falciparum parasites. In human populations, centuries of selective pressures have sculpted an intricate and heterogeneous immunogenetic landscape. Classical adaptations, such as hemoglobinopathies, are complemented by a diverse array of genetic polymorphisms that modulate innate and adaptive immune responses. These genetic traits, along with the acquisition of functional immunity following repeated exposures, mitigate disease severity but are continually challenged by the parasite’s highly evolved mechanisms of antigenic variation and immunomodulation. Such host adaptations underscore an evolutionary arms race that perpetually shapes the clinical and epidemiological outcomes. Intermediaries in malaria transmission have evolved robust responses to both natural and anthropogenic pressures. Their vector competence is governed by complex polygenic traits that affect physiological barriers and immune responses during parasite development. Recent studies reveal that these mosquitoes exhibit rapid behavioral and biochemical adaptations, including shifts in host-seeking behavior and the evolution of insecticide resistance. Mechanisms such as enhanced metabolic detoxification and target site insensitivity have emerged in response to the widespread use of insecticides, thereby eroding the efficacy of conventional interventions like insecticide-treated bed nets and indoor residual spraying. These adaptations not only sustain transmission dynamics in intervention saturated landscapes but also challenge current vector control paradigms, necessitating the development of innovative, integrated management strategies. At the molecular level, P. falciparum exemplifies evolutionary ingenuity through extensive genomic streamlining and metabolic reconfiguration. Its compact genome, a result of strategic gene loss and pruning, is optimized for an obligate parasitic lifestyle. The repurposing of the apicoplast for critical anabolic functions including fatty acid, isoprenoid, and haem biosynthesis highlights the parasite’s ability to exploit host derived nutrients efficiently. Moreover, the rapid accumulation of mutations, coupled with an elaborate repertoire for antigenic switching and epigenetic regulation, not only facilitates immune escape but also accelerates the emergence of antimalarial drug resistance. Advanced high throughput sequencing and functional genomics have begun to elucidate the metabolic epigenetic nexus that governs virulence gene expression and antigenic diversity in P. falciparum. By integrating insights from molecular biology, genomics, and evolutionary ecology, this study delineates the multifaceted co-adaptive dynamics that render malaria a recalcitrant global health threat. Our findings provide critical insights into the molecular arms race at the heart of host–pathogen vector interactions and underscore promising avenues for the development of next generation therapeutic and vector management strategies aimed at sustainable malaria elimination. Full article

Vector-borne diseases (VBDs) continue to pose a persistent global health challenge, disproportionately impacting low- and middle-income countries where surveillance and healthcare infrastructure are constrained. Within these countries, residents of remote island communities are particularly vulnerable to emerging VBD threats; however, they remain critically understudied. We conducted a community-based cross-sectional survey of 300 residents from Shahpori Island, Bangladesh, and Gaya Island, Malaysia, to assess knowledge, attitudes, and practices (KAP) related to VBDs. Using a structured questionnaire and mixed-effects Poisson regression modeling, we identified socio-demographic predictors of VBD-related knowledge and compared KAP outcomes across the two islands. Significant disparities were observed between the two settings: the Gaya Island residents demonstrated a higher level of awareness regarding VBDs and preventive practices compared to the Shahpori residents. Education was a strong predictor of VBD knowledge, with individuals possessing secondary education or above exhibiting significantly better knowledge (β = 0.2024, p = 0.0003). Marital status was also a significant factor, with unmarried respondents showing lower levels of knowledge (β = –0.1657, p = 0.0372). Age was positively correlated with VBD knowledge (β = 0.0051, p = 0.0119), indicating a gradual increase with age, while income, gender, occupation, and household size were not significantly associated. Despite basic awareness of VBD symptoms and transmission, detailed understanding of mosquito ecology, disease symptoms, and breeding prevention strategies was remarkably poor, especially among the Shahpori residents. Our findings highlight critical gaps in VBD-related knowledge and prevention behaviors shaped by socio-economic and educational disparities. Community-focused public health strategies including educational campaigns, establishment of health infrastructure, access to trained healthcare providers, and integrated vector control interventions are urgently needed to enhance resilience against emerging VBD threats such as drug-resistant malaria in remote island populations. 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

In the early 1900s, eastern mosquitofish (Gambusia holbrooki) and western mosquitofish (Gambusia affinis) were deliberately and globally introduced for the biological control of mosquito larvae. Subsequently, both species developed a reputation for causing impacts on native small-bodied fish, amphibian larvae, and other aquatic species. This led to both species being considered some of the world’s worst invasive species. Due to morphological similarities, organizations worldwide often consider these species jointly when discussing their introduction and impacts. Recent studies suggest these species differ in fundamental ways, which could affect invasion success. Our goal was to compare eastern and western mosquitofish behavior and invasion success. Replicate populations were collected from the U.S. states of Florida (eastern mosquitofish) and Louisiana (western mosquitofish) to assess variation in aggression, boldness, and sociability. Mesocosm trials were used to compare invasion success between species following introduction to an ecosystem occupied by another small-bodied poeciliid. Eastern mosquitofish caused more damage to similar-sized heterospecifics and western mosquitofish exhibited greater boldness. No differences were found in sociability between the two species. In mesocosms, impacts were observed for both mosquitofish species but were greatest for heterospecifics with eastern mosquitofish. This suggests that two invasive species, even with similar life history and morphology, can differ in traits related to invasion success and ecological impacts. It is important to correctly identify mosquitofish species when evaluating their invasion. Full article