Search Results (272)

Aedes aegypti transmits viruses to millions of people worldwide. Despite the availability of vaccines, control and monitoring of mosquitoes is mandatory, which in turn requires knowledge of microevolutionary population genetics. Genetic techniques permit the assessment of biological parameters directly linked to the epidemiological importance of the insect (polymorphism, migration, fitness). However, these techniques are costly to most health surveillance services. Even for research laboratories, genotyping and estimation of variability may be unfeasible and time consuming. We conjectured that the wing geometry of Ae. aegypti could serve as an alternative indicator of genetic variability in mosquitoes, as wing shape is a useful taxonomic marker determined by quantitative heritage. We investigated this conjecture by testing if wild Ae. aegypti populations with high genetic variability had higher wing morphological diversity than inbred colonised populations. Using wing geometric morphometrics and microsatellite DNA genotyping of some populational samples, we confirmed this conjecture. The morphological diversity index was partly correspondent with genetic variability indexes such as theta, gene diversity and alleles per locus. Our findings, although circumscribed to the populational samples studied, indicate that wing geometry may be used as a cheap and quick semi-quantitative proxy for genetic variability. Full article

Yellow fever (YF) is an infectious disease caused by the yellow fever virus (YFV), an arbovirus of the Flaviviridae family. It is transmitted through the bite of infected mosquitoes of the Culicidae family and affects both humans and non-human primates (NHPs). This study aimed to investigate the sylvatic Culicidae fauna and the occurrence of natural YFV infection in a microregion of southern Santa Catarina, Brazil, an area recently affected by a sylvatic YF outbreak. Entomological collections were conducted between January and February 2023 in five municipalities with confirmed viral circulation. Natural YFV infection was assessed using RT-LAMP. A total of 4352 female culicids were collected, representing at least 32 species, including several key sylvatic YFV vectors. Haemagogus leucocelaenus was identified in all sampled municipalities, whereas Haemagogus (Haemagogus) janthinomys Dyar, 1921, historically considered the primary vector of sylvatic YFV in Brazil, was not detected. Mosquitoes from the genera Aedes Meigen, 1818; Haemagogus Williston, 1896; Psorophora Robineau-Desvoidy, 1827; and Sabethes Robineau-Desvoidy, 1827 were tested for YFV. Only one pool, composed of Sabethes albiprivus, tested positive, yielding a minimum infection rate (MIR) of 11.6. This is the first record of natural YFV infection in Sa. albiprivus in southern Brazil, and only the third record globally, highlighting its potential role as a secondary vector in maintaining viral circulation in sylvatic environments. Based on species presence and abundance, Hg. leucocelaenus is likely to have acted as the primary YFV vector in the study area. The composition of the culicid fauna, coupled with the detection of YFV in sylvatic vectors, indicates an ongoing epidemiological risk. These findings underscore the need to strengthen entomological surveillance and expand YF vaccination coverage in affected and neighbouring regions. Full article

Mosquitoes are recognized as the arthropod group with the greatest vectorial capacity, and the viruses they transmit constitute a significant concern in the context of global One Health. In addition, these insects act as hosts for a wide diversity of insect-specific viruses (ISVs), which exclusively infect arthropods. Expanding knowledge of ISVs is particularly relevant, given their potential influence on arbovirus replication and their role in elucidating the evolutionary processes that shape virus–vector interactions. In this study, we report the isolation and molecular analysis of three negeviruses associated with different mosquito species of the genera Culex, Coquillettidia, Mansonia, and Ochlerotatus, collected in Belém, Pará State, in the Brazilian Amazon: Loreto virus, Wallerfield virus, and a putative new species, designated Terra firme virus. Eleven pools exhibited cellular alterations consistent with cytopathic effects in invertebrate C6/36 cells but showed no evidence of replication in vertebrate Vero cells. Notably, simultaneous infections by two or three negeviruses were detected in some mosquito pools, indicating the occurrence of multiple viral infections within individual samples. Genomic analyses revealed that the isolated strains share conserved domains with previously described isolates from other countries. Phylogenetic inferences demonstrated that the investigated strains are classified within the clades Nelorpivirus and Sandewavirus. Taken together, these findings expand the currently known diversity of the negevirus group and contribute to a more comprehensive understanding of its host range and geographic distribution. Full article

Urban coastal wetlands constitute important ecological interfaces where human activities, wildlife, and arthropod vectors interact, potentially increasing the risk of pathogen transmission. In the city of Veracruz, Mexico, several interdunal lagoons have been incorporated into urban areas and are intensively used for recreational activities; however, information on their mosquito fauna remains limited. This study aimed to characterize mosquito species composition, abundance, and diversity in three urban recreational interdunal lagoons in Veracruz. Adult mosquitoes were collected weekly during the rainy season (June–September) 2023 using CDC light traps. Specimens were identified based on morphological characters using standard taxonomic keys, including genitalia dissections for male specimens when necessary. Species richness, sampling completeness, and community structure were evaluated using non-parametric richness estimators, diversity indices, species accumulation curves, and similarity analyses. A total of 1465 adult mosquitoes belonging to 11 species and five genera were collected. Mosquito assemblages were characterized by low species richness and a marked dominance of Culex panocossa and Culex quinquefasciatus across all lagoons. Diversity indices were low, and species composition showed a high degree of similarity among sites. Notably, Uranotaenia apicalis was recorded for the first time in the state of Veracruz, expanding its known geographical distribution. These findings indicate that urban interdunal lagoons support simplified mosquito communities dominated by disturbance-tolerant species, highlighting their potential epidemiological relevance and the need for targeted vector surveillance in urban coastal environments. 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

Accurate identification of disease vectors is crucial for public health, yet distinguishing morphologically similar species demands significant taxonomic expertise and data resources. This study proposes MVP-Net, an AI-driven framework designed to extract a minimal sufficient set of diagnostic anatomical views from multi-view imagery for efficient identification. The framework was evaluated on regionally collected datasets of Calyptratae (8 views) and Culicidae (11 views) from routine surveillance in Shanghai. Under all-view fusion, MVP-Net achieved Top-1 accuracies of 87.04% for Calyptratae and 100% for Culicidae. After Pareto-based view optimization, the required input was reduced to 5 views for Calyptratae and 2 views for Culicidae, lowering computational cost by 37.49% and 81.82%, respectively, while retaining comparable classification performance (86.11% for the recommended Calyptratae configuration and 100% for the recommended Culicidae configuration). These results show that MVP-Net can reduce view redundancy while preserving comparable identification performance within the current Shanghai surveillance setting, providing a practical approach for optimizing regional multi-view auxiliary identification workflows. Full article

The management of Culex pipiens (Diptera: Culicidae), key vectors of arboviruses like West Nile virus, necessitates sustainable alternatives to chemical insecticides. This study screened indigenous entomopathogenic fungi (EPF) from forest soils in Achaia, Greece, for their larvicidal efficacy against Cx. pipiens biotype molestus. Fifteen fungal isolates were obtained via insect baiting and identified as Beauveria and Metarhizium species. A comprehensive bioassay at 1 × 10⁸ conidia mL⁻¹ revealed significant variation in pathogenicity after 72 h. Two isolates, Beauveria bassiana (BB) (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (K3(1)) (Hypocreales: Clavicipitaceae), exhibited the highest virulence among the tested isolates, each causing 60% mortality with a rapid median lethal time (LT₅₀) of ~18.5 h. Survival analysis, Cox modeling, and non-linear kinetic modeling (Gompertz/Richards) classified three distinct virulence clusters: high/rapid, moderate/consistent, and low/delayed. A pathogenicity network analysis and a composite virulence index further validated BB and K3(1) as the most effective candidates. These results demonstrate the high isolate specificity of fungal efficacy and underscore the importance of screening local fungal diversity. The identified high-virulence isolates represent promising, environmentally sound candidates for the development of targeted biopesticides. Future research should focus on formulation for aquatic environments and integration into resistance-resilient integrated vector management programs. Full article

Arthropod-borne diseases are increasingly reported in temperate regions, reflecting the combined effects of climate variability, environmental change, and global movement of humans and animals. This review addresses how different arthropod vectors contribute to disease emergence in these regions and aims to identify shared and vector-specific drivers of transmission. A comparative synthesis of recent literature was conducted focusing on mosquitoes, ticks, sandflies, and biting midges, using a stage-based framework encompassing introduction, establishment and overwintering, seasonal amplification, and spillover to humans or animals. The analysis shows that although climate-related factors commonly facilitate expansion, the biological traits of each vector group strongly influence persistence, transmission dynamics, and detectability. Differences in overwintering capacity, host associations, and dispersal mechanisms result in distinct emergence pathways and surveillance challenges. The findings indicate that early warning indicators and control options are highly context dependent and cannot be applied uniformly across vector groups. This narrative review concludes that effective preparedness in temperate regions requires surveillance and intervention strategies tailored to specific vectors and ecological settings. Full article

Phytotelmata are small, plant-held water pools that support unique assemblages of fauna and flora. Aquatic Diptera are a significant component of these microecosystems. Based on an exhaustive review of over 100 years of published literature, a global database of phytotelmata-associated aquatic Diptera with Bromeliaceae and Zingiberales (7 families) was compiled to explore diversity and ecology and identify gaps in the research. This database is designed to provide a valuable baseline and to serve as an objective, informed tool for future monitoring and research. A total of 4979 unique associations between aquatic Diptera larvae and 117 species in 26 genera of Bromeliaceae and 27 species in 10 genera across 6 families of Zingiberales were assembled in the database. These reported aquatic Diptera span 369 species, 80 genera, and 14 families, and include taxa with diverse ecological roles as detritivores, filter feeders, predators, and prey. Mosquitoes (Culicidae) had the greatest number of documented species (227), and non-biting midges (Chironomidae) had the greatest number of documented genera (26) in the dataset. Several mosquito vectors (e.g., Anopheles, Aedes, and Culex) also complete their life cycles in these habitats, although records of vector mosquitoes compose only 6% of the assembled data. Because phytotelmata provide year-round aquatic refugia, they sustain regional aquatic Diptera diversity yet are threatened by habitat loss and other anthropogenic pressures. Furthermore, despite the important role of phytotelmata in freshwater ecology, diversity in these ephemeral freshwater habitats remains under-documented. This comprehensive analysis of existing literature establishes the first global baseline for aquatic Diptera in phytotelmata and offers a foundation for biodiversity assessments, conservation strategies, and future ecological research. Full article

Mosquitoes (Diptera: Culicidae) exhibit vertical stratification patterns in forest environments, a fundamental ecological aspect for understanding niche occupation patterns, host-seeking behavior, and consequently arbovirus transmission mechanisms. Despite the relevance of this topic, available studies mostly focus on genera such as Aedes, Haemagogus, and Sabethes which are traditionally associated with arbovirus transmission. There are still important gaps regarding stratification and seasonality in the Mansoniini tribe, whose biology and epidemiological role remain underexplored, especially in highly biodiverse ecosystems such as the Atlantic Forest. This study evaluated the influence of seasonality and vertical stratification on the mosquito community, with a detailed focus on the Mansoniini tribe, in an Atlantic Forest fragment in Brazil, between May 2023 and December 2024. Captures were performed monthly using CDC light traps positioned at 1.5 m and 10 m heights, and specimens were morphologically identified. A total of 880 mosquitoes from nine genera and 24 species were captured, of which 91 (10.3%) belonged to the Mansoniini tribe. The most abundant species were Coquillettidia fasciolata and Mansonia titillans, recorded in both strata. Our results indicate no marked vertical segregation for the studied mosquito community in this specific location, but a strong influence of seasonality, particularly for the Mansoniini tribe, reinforcing the role of meteorological data on the population structure of these species. These site-specific findings offer a foundational ecological portrait and a robust methodological template for a neglected taxon. They generate critical, testable hypotheses about niche partitioning in fragmented forests and underscore the necessity for broader spatial replication to disentangle the relative influence of seasonal versus vertical drivers in similar ecosystems. Full article

Advances in diagnostic techniques, along with environmental changes driven by human activity, have intensified the surveillance and monitoring of virus and arbovirus circulation on the Amazon. These efforts have increased the detection of insect-specific viruses in field-collected hematophagous arthropods. This study reports the first isolation of the Aguas Brancas virus from mosquitoes collected in the Brazilian Amazon and in a rural area of Brasília, Federal District, Brazil. Arthropods of the family Culicidae, genus Limatus durhamii, were collected at ground level in forest fragments. Sample BEAR812610 originated from Ananindeua, Pará, within the Evandro Chagas Institute’s grounds, and sample BEAR839941 from a forest fragment in Brasília (Ceilândia—Núcleo Rural Boa Esperança, Site B4). Specimens were identified to the species/genus level, macerated, and the supernatant inoculated into C6/36 and Vero cell cultures for viral isolation. The presence of arboviruses was determined by indirect immunofluorescence using antibodies against major arbovirus groups. Positive samples were sequenced for nucleotide and amino acid identification, and phylogenetic analysis confirmed the virus as belonging to the genus Orthoflavivirus. This represents the first report of the isolation and characterization of the insect-specific Aguas Brancas virus. Full article

Zoological gardens represent unique sites for vector and vector-borne disease studies. They offer suitable breeding habitats for vector development and a diverse range of vertebrate hosts for blood feeding of insect vectors. This study aimed to assess the prevalence of avian blood parasites (Haemosporida, Trypanosomatida) in wild-caught mosquitoes (Culicidae) and Culicoides biting midges (Ceratopogonidae) from the largest and oldest zoo in Lithuania. Insects were collected in May–August 2023 using UV-light, CDC and BG-Sentinel traps; collected material was analysed using both microscopy and PCR-based methods for parasite detection. Overall, 504 parous biting midges (10 species) and 59 mosquitoes (three species) were investigated. Haemosporidians (Haemoproteus minutus (hTURDUS2), H. homogeneae (hSYAT16), and H. asymmetricus (hTUPHI01)) were identified in 5.4% of the 174 tested biting midges. Haemoproteus asymmetricus hTUPHI01 sporozoites were seen in only one individual of Culicoides kibunensis. Of 108 Culicoides females, 3.7% carried trypanosomatids—parasites infecting birds (Trypanosoma bennetti group) and mammals (T. theileri group). Among the 59 tested mosquitoes, two (3.4%) Cx. pipiens/torrentium mosquitoes were found to be PCR-positive for trypanosomatids (T. culicavium and Crithidia brevicula). No haemosporidian parasite DNA was detected in the mosquitoes examined. This pilot study indicates that avian blood parasites circulate within the Lithuanian Zoo, highlighting the need for further research on transmission pathways, vector–host interactions, and potential risks. Full article

Populations of Culex pipiens, which is considered a primary vector of West Nile Virus, are not uniformly shaped, and hence, they are difficult to work on, not only because of the complex structure of the species but also due to the possible deformations caused by several factors like temperature, pH, parasite, and bacterial density. Larval density is another crucial factor. This study summarizes the effects of larval density in Cx. pipiens as a model of experimental semi-controlled ecomorphs by two different geometric morphometrics methods. The landmark-based method explains that dimorphism is clearly visualized in both the size and shape of the wings. It also shows that females and males have gradually traceable deformations. When the population reaches a high larval density, which is calculated as approximately 0.5 cm³/individual or, in other words, 1 larva/mL in Cx. pipiens, it can be considered a breaking point, where deformations in shape are observed through all study periods, indicating that it is effected separately and varies independently from the other factors. The wings become smaller in both sexes as the larval density increases. Similar results are obtained by Elliptic Fourier Analysis, which explains the difference in the contour of the wing, regardless of where the landmarks on the veins are located. 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

Pollution with heavy metals, such as cadmium (Cd), can significantly affect insect growth, development, and behavior. The midgut is an essential organ for stress response. Chitin synthase-2 (CHS-2) is closely associated with forming the peritrophic membrane (PM). The fourth-instar larvae of Aedes albopictus were exposed to varying concentrations of Cd. The results showed that Cd inhibited chitin synthesis and metabolism-related genes, but thickened the midgut PM, indicating that the larvae could respond to Cd stress through the midgut PM. Silencing CHS-2 by RNA interference resulted more severe vacuolization and malformation of midgut epithelial cells without midgut PM protection. Additionally, there was an intensified redox reaction, upregulated expression of metallothionein (MT) and heat shock proteins 70 (HSP70), and increased activity of antioxidant enzymes at some scattered time points. This study confirms that CHS-2 is involved in oxidative stress induced by Cd exposure by regulating PM formation. This study also contributes to further understanding the resistance mechanism of Ae. albopictus under Cd stress, thereby establishing a theoretical foundation for the future studies of them, which is concerned with the possibility of Ae. albopictus as a water environment detection and the control of Ae. albopictus based on resistance mechanism. Full article