Mosquitoes are a source of concern because they transmit many infectious diseases, including Zika virus, chikungunya, and malaria. Accurate and rapid identification of mosquitoes is essential for disease surveillance and control. Genetic diversity in mosquito species, resulting from adaptation to different environments, leads to many differences in morphological characteristics. Traditional identification methods relying on morphology can be time-consuming and unreliable. The study aimed to identify medically and veterinary significant adult mosquito species throughout 2021 in Buraydah City, Kingdom of Saudi Arabia (KSA). We collected adult mosquitoes using Black Hole light traps in the city. The mosquitoes were morphologically identified using traditional identification keys and characterized by using the mitochondrial cytochrome oxidase c subunit I (COI) barcode regions. Although the genetic sequences we discovered do not necessarily represent new records, they do represent species with a long history of evolutionary independence, at least among adult mosquito species in KSA, especially in Buraydah city. Both morphological and molecular data identified five mosquito species: Culex pipiens (Linnaeus, 1758), Cx. sitiens (Wiedemann, 1828), Aedes aegypti (Linnaeus, 1762), Ae. caspius (Pallas, 1771), and Anopheles dthali (Patton, 1905). These species correspond to those from Kenya, India, KSA, and Iran with genetic variation. Aedes aegypti was confirmed for the first time in Buraydah city. DNA barcoding is a useful tool that can overcome inefficiencies and difficulties and complement traditional taxonomy.
Mosquitoes (Diptera: Culicidae) are important vectors of human and animal pathogens. Balkan countries in the southeastern part of Europe exhibit a diverse mosquito fauna and can act as a crossway for both natural and anthropogenic introduction. Some countries however lack data on mosquito fauna distribution, diversity, and pathogen circulation. mosquitoes were trapped in all seven districts of Kosovo in July and August of both 2022 and 2023, then were investigated for the presence of pathogens using PCR-based methods. A total of 144 different locations were surveyed using up to three CDC miniature light traps. Individual trapped mosquitoes were morphologically identified, then pooled, and DNA/RNA was isolated. Identification was confirmed by cytochrome oxidase I (COI) barcoding, and PCR-based pathogen screening was performed, targeting the medically relevant Filarioidea, Plasmodium and trypanosomatid protozoans as well as arboviruses (West Nile, Dengue and Zika virus). Altogether 6491 mosquitoes belonging to 18 species in six genera were trapped, identified, and screened in 1122 pools. Of 986 female pools, 21 pools (2.1%) tested positive for DNA of filarioid helminths (Dirofilaria immitis and D. repens), 52 pools (5.3%) tested positive for avian Plasmodium DNA, and 82 (8.3%) tested positive for trypanosomatid DNA. This study thus presents the most extensive survey of mosquitoes and their parasites in Kosovo to date, providing data on the prevalence of the animal and human pathogens, Filarioidea, Plasmodium and Trypanosoma.
Technological advancements in insecticide-based formulations have emerged as a promising method to address the problem of mosquito control. However, the requirement for tools that could be impactful in targeting mosquito populations proliferating in the cryptic habitats is vital. The current study was performed to demonstrate the mosquito-vectored auto-dissemination of pyriproxyfen from the surfaces painted with pyriproxyfen-based paint. Paint formulation containing six different concentrations of pyriproxyfen (0.075%, 1%, 2%, 4%, 8%, and 16% in w/w) was applied on 15 cm × 15 cm pieces of metal, wood, plastic, and ceramic materials. Adult females (5-7 days old) were allowed to blood-feed and exposed to the treated material surfaces for 1 h using the WHO cone bioassay. After pyriproxyfen-based paint exposure, the females were transferred to small cages for egg laying. Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS) was used to estimate the concentration of auto-disseminated pyriproxyfen in breeding water. The sterilisation effect of pyriproxyfen was observed through a reduction in fertility and fecundity, whereas the auto-dissemination impact was recorded through metamorphosis failure in the aquatic stage of Aedes aegypti kept in breeding water. There was a concentration-dependent change in the average number of eggs hatched (F = 5.8; p = 0.004); however, the average number of eggs laid was not concentration-dependent (F = 2.3; p = 0.1). For mosquito aquatic stages, there was a concentration-dependent decline in pupation and adult emergence rate (p < 0.0001). For the highest concentration of pyriproxyfen used for mosquito exposure, 7.8±0.1 ppb of pyriproxyfen was estimated in breeding water using the LC-MS/MS method. Results indicated that mosquitoes successfully auto-disseminated pyriproxyfen from the painted surfaces to the breeding habitats. Such formulations could be useful in intervention programmes after field-scale evaluation.
Metagenomics or metaviromics is emerging as a powerful technology for pathogen surveillance and pandemic preparedness. Mosquitoes are important vectors for transmission of many emerging viruses responsible for numerous outbreaks. Monitoring mosquitoes becomes essential to investigate its virome which leads to understanding of disease dynamics and allow preventive actions. In this study, shotgun metagenomic methodology using Ion GeneStudio S5 System was optimized for exploration of viral diversity. A total of 1913 Aedes larvae were collected from Central India during post monsoon season of 2024. Aedes larvae reared to adulthood and processed for sequencing using Ion Torrent S5 platform. Computational analyses were performed using three bioinformatic pipelines: Chan Zuckerberg ID (CZ ID), Genome Detective Platform and the Galaxy Platform. A mock database of 11 known viruses was created as well as publicly available NCBI Sequence Read Archive (SRA) datasets were used to validate all three pipelines. In terms of detection accuracy, Genome Detective and CZ ID performed exceptionally well and therefore may be suitable for future mosquito virome surveillance studies. We found presence of viruses viz. Alphamesonivirus cavallynense and Phasivirus phasiense dominating in all samples. Dengue virus was detected in one sample by CZ ID, whereas Wenzhou sobemo-like virus, Hubei mosquito virus 2, Cell fusing agent virus found most commonly among samples. Other viruses found like Aedes anphevirus (AeAV; genus Glybovirus), Aedes totivirus, Verdadero virus and Chaq-like virus. Variation in the result among different pipelines are likely attributable to incorporation of different viral reference databases, classification algorithms, metrics and analysis parameters. To the best of our knowledge, this study represents the first metagenomic study of mosquitoes using Ion GeneStudio S5 platform in India. The findings provide a comparative evaluation of the metagenomic pipelines and elucidates detailed information of each pipeline and its working for future studies.
Internal controls are essential to ensure the reliability of molecular assays, confirming the integrity of nucleic acid extraction and testing process. This is particularly important in entomovirological surveillance, which relies on molecular testing of field-collected arthropod vectors. A key challenge is identifying a control target conserved among diverse vector species. We designed a novel primer-probe set for hydrolysis probe-based real-time PCR, targeting the actin-1 gene and assessed its performance across 21 mosquito and 9 sand fly species in Israel. The assay performance was compared to that of the ribosomal protein S17 (RpS17) assay, one of several endogenous controls reported in mosquito studies. The actin-1 RT-qPCR assay detected all mosquito and sand fly species tested, whereas the RpS17 assay covered only 11 mosquito and 4 sand fly species. Varying mosquito numbers per surveillance pool showed a negative correlation between pool size and actin-1 cycle threshold (Ct) values, confirming consistent detection across sample sizes. We further integrated actin-1 into 3 multiplex RT-qPCR assays: actin-1 + West Nile virus, actin-1 + Usutu virus, and actin-1 + representative phleboviruses: Toscana virus and Sandfly fever Sicilian virus. All assays reliably detected both actin-1 and their respective viral targets, with serial dilutions showing high efficiency and linearity. Differences between singleplex and multiplex testing were minimal showing no significant impact on assay sensitivity. Overall, the actin-1 RT-qPCR assay showed broad species coverage and reliable performance in multiplex RT-qPCR using field-collected specimens, supporting its use as an endogenous internal control in molecular arbovirus surveillance.
Ivermectin is used in the treatment of several neglected tropical diseases. Studies have shown that it effectively kills anopheline mosquitoes. However, the relationship between the pharmacokinetic properties and mosquito-lethal effects have not been described quantitatively. Pharmacokinetic properties and mosquito-lethal effects associated with a single oral administration of ivermectin were evaluated in two healthy volunteer trials in Thailand. All data were pooled and analysed using nonlinear mixed-effect modelling. Ivermectin and metabolites were described by a parent-metabolite model. When co-administered with dihydroartemisinin-piperaquine, a reduced elimination clearance (41%) and a slower absorption (32%) of ivermectin was identified, resulting in higher exposures. Different peripheral volume of distributions of ivermectin in men and women were also observed (75% higher in females). Individual pharmacokinetic profiles were incorporated in a sigmoidal Emax model, which were used to quantify the relationship between ivermectin exposure and mosquito-lethal effects. The integrated models described successfully the observed mortality of both Anopheles dirus and An. minimus. The final models were used to illustrate the potential impact on vector-control associated with ivermectin administration. In conclusion, ivermectin and its metabolites showed effective mosquito-lethal effects. The developed pharmacometric framework could be a useful tool in the evaluation of ivermectin as a potential vector-control agent in malaria elimination campaigns.
Sugar feeding is essential for mosquito survival and reproduction, yet its temporal dynamics and species-specific patterns remain poorly characterized under field conditions. We deployed a low-cost, continuous infrared video surveillance system at artificial sugar bait stations at two coastal Florida habitats (hammock forest and mangrove swamp) over a 10-night period, recording 113 mosquito visitation events while concurrently sampling the local mosquito assemblage using CO2-baited and sucrose-baited traps. All visitation events occurred during the scotophase, following a pronounced bimodal pattern with a primary peak at 21:00 and a secondary pre-dawn peak at 06:00. Individual feeding event duration was consistent across the night (22.6 ± 16.4 s), suggesting physiological rather than circadian control of feeding bout length. A total of 12,490 mosquitoes representing 22 species were collected (12,118 from CO2 traps and 372 from sucrose traps), with Aedes taeniorhynchus, Culex nigripalpus, and Deinocerites cancer as the dominant taxa. Sucrose traps were highly selective, capturing a significantly lower proportion of host-seeking (unfed) individuals than CO2 traps. The local abundance of Ae. taeniorhynchus had a strong positive association with station visitation (r = 0.9), whereas De. cancer showed a negative association (r= -0.63). Weak associations for other taxa indicate that sugar-seeking is not strictly density-dependent and varies across the mosquito assemblage. These observations support the notion that species-specific foraging patterns and habitat context drive sugar-bait utilization. Our findings emphasize that localized population dynamics must inform the strategic deployment of attractive toxic sugar baits (ATSBs) in vector control programs.
Aedes aegypti is an important vector of human pathogens, including dengue and chikungunya viruses. We examined midgut miRNA expression changes in Ae. aegypti following infection with Escherichia coli, Staphylococcus aureus, and Beauveria bassiana. We identified 19 differentially expressed miRNAs in the midgut of fourth-instar larvae infected with E. coli, 42 in larvae infected with S. aureus, and 134 in adult mosquitoes. The highest number of differentially expressed miRNAs (160) was observed in mosquitoes infected with B. bassiana. Among these, aae-miR-375 showed the most pronounced change, with nearly 96% downregulation after S. aureus infection. The interaction between aae-miR-375 and Ae-bre-4 was validated using dual-luciferase assays. These results indicate that different pathogens induce distinct midgut miRNA expression profiles in Ae. aegypti. Furthermore, we identified Ae-bre-4 as a target of aae-miR-375, providing new insights into the pathogen-miRNA-mRNA interactions that underlie mosquito immune responses. Collectively, these findings improve our understanding of mosquito immunity and may inform future vector control strategies.
Nonnative and invasive mosquito species threaten public and veterinary health in the southern USA by introducing pathogens into new regions, making early detection of these species essential. To address this need, the Mosquito Biodiversity Enhancement and Control of Non-native Species (Mosquito BEACONS) Working Group provided training to mosquito surveillance professionals between 2021 and 2024. More than 190 individuals from public health, pest control, and research sectors participated. A 12-question online survey evaluated participant engagement, awareness, and application of skills learned. Twenty-two participants completed the survey, and results indicated that the training led to measurable behavioral changes, with participants applying the learned skills when returning to their home institutions. This study represents the first evaluation of an integrated pest management (IPM) training program focused on invasive species and offers a framework for improving future IPM training evaluations.
Mosquito-borne diseases remain a major public health concern in sub-Saharan Africa, yet the ecological drivers of mosquito community structure in intra-urban environments are poorly understood. This study aimed to assess how habitat heterogeneity, seasonality, and environmental gradients shape mosquito communities in Franceville. A longitudinal survey was conducted from July 2023 to July 2024 using 10 CDC light traps deployed weekly for three consecutive nights. Mosquitoes were identified morphologically and environmental, climatic, and urban variables were recorded. Community structure was analysed using diversity indices, principal component analysis (PCA), canonical correspondence analysis (CCA), and Variation Partitioning (VarPar). Species sensitivity to environmental gradients was quantified, and variation partitioning was used to assess the relative contributions of predictor groups. A total of 6794 mosquitoes representing 24 species across 7 genera were collected. Community composition varied significantly across habitat and season, with higher diversity in forest-associated habitats and more even assemblages in savannah environments. Multivariate analyses revealed distinct ecological responses among genera: Anopheles species showed high sensitivity to environmental gradients, whereas dominant Culex species exhibited broad ecological tolerance. Aedes aegypti was associated with savannah habitats and the rainy periods, while Ae. albopictus displayed marked ecological plasticity. Variation partitioning indicated that environmental variables explained a larger share of community variation than climatic and urban predictors, with additional effects from their interactions. Mosquito communities in southeastern Gabon are primarily structured by fine-scale habit heterogeneity and seasonal dynamics. These findings highlight the importance of integrating ecological complexity and species-specific responses into vector surveillance and control strategies in rapidly urbanising African settings.
Understanding the occurrence of arthropods in the Arctic relies heavily on distributional and taxonomic evidence, yet substantial gaps and inconsistencies in available data complicate interpretation. These limitations impact our understanding of ecologically-and medically-important groups such as the mosquitoes (Diptera: Culicidae), whose Arctic diversity and biogeography remain poorly resolved. Many species were originally described from limited material, often using morphological traits that differ from those observed in more thoroughly studied southern populations. Sparse and uneven sampling across the Arctic limits our ability to accurately assess species distributions, and missing or incomplete metadata further diminishes the scientific value of existing specimens. Collectively, these issues obscure patterns of biodiversity, hinder detection of climate‑driven range shifts, and constrain efforts to evaluate the vector potential of species capable of transmitting arboviruses. As concerns grow regarding the northward expansion of mosquito‑borne pathogens, the absence of reliable baseline data poses a major challenge for assessing current and future risks to human and animal health in Arctic ecosystems. This review synthesizes historical records of Canadian Arctic mosquitoes from early natural history expeditions beginning around 1820 to the present. We evaluate the taxonomic reliability, geographic accuracy, and research relevance of these records to determine which can serve as credible baselines for contemporary biodiversity assessments. By clarifying the strengths and limitations of the historical dataset, this review aims to support improved species distribution modeling, inform future surveillance efforts, and guide research priorities in a rapidly changing Arctic.
Mosquito-borne diseases remain an important global public health concern, and increasing insecticide resistance has strengthened interest in complementary personal protection tools. This study evaluated the short-term dermal tolerability and laboratory repellency of MosShield, a ready-to-use topical spray formulated with 6% w/w Litsea cubeba essential oil. Non-confidential formulation quality-control parameters, including appearance, homogeneity, pH, density, and apparent viscosity, were recorded to support formulation consistency before testing. Short-term dermal tolerability was assessed using a human skin-patch test in 48 healthy volunteers, with no visible skin reactions observed up to 96 h after application. Repellency assays were conducted following the World Health Organization arm-in-cage protocol against three medically important mosquito species: Aedes aegypti, Anopheles dirus, and Culex quinquefasciatus. The formulation showed species-dependent repellency, achieving median complete protection times of 225 min against Cx. quinquefasciatus and 120 min against both Ae. aegypti and An. dirus. These findings provide product-relevant laboratory evidence supporting further evaluation of the 6% L. cubeba essential oil spray as a plant-based topical mosquito repellent under semi-field and field conditions.
To identify novel host factors essential for orthoflavivirus replication, we performed proteomic profiling of endoplasmic reticulum fractions isolated from cells infected with Dengue virus or Zika virus (ZIKV). Among the enriched proteins, the splicing factor U2AF2 and its heterodimeric partner U2AF1 were found to be critical for efficient viral infection, functioning at the viral protein synthesis stage. The arginine/serine-rich (RS) domain and the first zinc knuckle (Zn1) of U2AF1, as well as nearly all domains except the RS domain of U2AF2, were essential for their proviral function. Disruption of the U2AF1-U2AF2 interaction potently suppressed ZIKV infection. U2AF1 and U2AF2 partially localize to the cytoplasm, and notably, the cytoplasmic U2AF2 was predominantly a truncated form that was sufficient to support viral replication. Both U2AF1 and U2AF2 bind to viral RNA, with U2AF1 binding being dependent on U2AF2. Interestingly, trans-complementation of the Aedes aegypti homolog u2af38 into U2AF1-knockout cells restored ZIKV replication, whereas expressing u2af50 in U2AF2-knockdown cells did not. However, knockdown of either u2af38 or u2af50 significantly inhibited the flavivirus replication in mosquitoes. Together, these findings reveal that flaviviruses co-opt host splicing factors in both human cells and mosquitoes, underscoring a conserved cross-species mechanism of viral exploitation.
Drug resistance hampers malaria treatment and control. Resistance to nearly all clinically used antimalarials has emerged and spread globally. With multi-drug-resistant parasites now on the rise, understanding resistance mechanisms and their ability to spread is crucial for optimal treatment and control strategies. Clindamycin is an apicoplast-targeting antimalarial used as a partner compound in second-line treatment combinations, but mechanisms of clindamycin resistance remain largely unexplored, and it is unclear whether resistant parasites could spread readily. We selected in vitro for clindamycin resistance in African and Southeast Asian strains of Plasmodium falciparum. All resistant lines carried mutations in the apicoplast-encoded large ribosomal subunit RNA (23S rRNA), reminiscent of clindamycin resistance mechanisms found in bacteria. We recovered three different mutations, all located in the peptidyl transferase region of apicoplast 23S rRNA. Each 23S rRNA mutation was associated with >20-fold resistance, although some mutants grew extremely poorly in vitro and therefore may lack clinical relevance in vivo. We assessed how well our most vigorously growing 23S rRNA mutant could infect Anopheles mosquitoes and found a modest reduction in vector infectivity, indicating that high-level clindamycin resistance is likely to be transmissible in the field. This is in contrast to atovaquone resistance, which exhibits a total block to transmission (and hence spread), but is more pronounced than P. falciparum azithromycin resistance, which does not significantly impair development in the mosquito.
Integrating human behavioral data with data on malaria vector biting rates can help to quantify human exposure to malaria vectors and identify gaps in protection; however, to date, the availability of necessary human location and behavior data have been more limited as compared to that of corresponding entomological data. To expand the data available for use in vector-human data integrations, this case example explored the process and interpretations of integrating human behavior estimates from the Malaria Behavior Survey (MBS), a large-scale cross-sectional survey measuring behaviors and their determinants, with routinely collected VectorLink entomological surveillance data in Central Malawi. This study followed established guidance on vector-human data integration to guide extraction of necessary data inputs from existing, routinely collected data. Hourly nighttime human behavior and location estimates, as well as population insecticide treated bednet (ITN) use rate, were derived from questions in the Malawi MBS, conducted in Malawi in May-July 2021. Hourly nighttime human biting rates were derived from human landing catches (HLCs) carried out by VectorLink in Malawi in June 2021. Human and vector data were then integrated to provide weighted estimates of exposure to vector bites, accounting for proportions of people indoors or outdoors, and protected by ITNs, each hour of the night. When accounting for mosquito and human location, most exposure to vector bites was estimated to occur indoors (96%), at times when people were asleep (87%). Although most mosquito bites occurred indoors during sleeping hours-when ITNs could offer protection-only 35% of all exposure to bites was estimated to be prevented, considering that the population-level usage rate of ITNs was only 40%. ITN access, which was only 39%, was identified as an important factor contributing to the protection gap. This case example suggests that integrating routinely collected entomological and human behavioral data can provide programmatically relevant insights. Future studies or programs may consider data integration of similar sources to better inform vector control or social and behavior change activities.
Long-lasting Insecticide Nets (LLINs) are central to malaria prevention, but their effectiveness is threatened by the increasing pyrethroid resistance and low bed net utilization in malaria-endemic regions globally. This study formulates a genotype-specific compartmental model accounting for malaria transmission. It incorporates the blocking and insecticidal killing effects of LLINs, and pyrethroid-induced fitness costs, to evaluate the impact of LLIN utilization on malaria and resistance dynamics. Reproductive numbers with and without LLINs were derived, and sensitivity analysis performed. This analysis showed that the utilization of LLINs and their effectiveness against pyrethroid-resistant vectors have the strongest effect in reducing malaria transmission in both Sobol and partial rank correlation coefficient PRCC analyses. The baseline scenario and four LLIN utilization scenarios (standard, three-year, two-year and one-year) were simulated over nine years to track malaria transmission, mosquito population and evolution of resistance. These were assessed, with pyrethroid-only nets deployed in the first two campaigns and pyrethroid piperonyl butoxide (PBO) nets deployed in the third campaign. Results showed that, despite an initial LLIN coverage of 81%, protection against malaria infection by both pyrethroid-only and pyrethroid-PBO nets was not sustained over the campaign period and this worsened with lower utilization levels. Pyrethroid-PBO nets provided greater mosquito suppression and better protection under standard utilization, but their advantage over pyrethroid-only nets declined with lower utilization. The study further demonstrated that repeated pyrethroid-only campaigns accelerate the evolution of pyrethroid resistance, but PBO nets counteract this trend particularly when such resistance carries a higher fitness cost. Although lower utilization levels slowed resistance evolution, these scenarios do not represent an epidemiologically viable malaria control strategy.
Gaps in unimproved house structures, especially in eaves and windows, allow mosquito entry, increasing indoor vector-borne disease transmission. Simple modifications to such houses may reduce human exposure, and insecticide treatment may kill mosquitoes, benefiting all community members. This study evaluated insecticide-treated screening (ITS) for eaves and windows, incorporated with deltamethrin and piperonyl butoxide (PBO), compared to a permethrin and PBO-treated bednet in Tanzania. A randomised Latin-square design (4 × 4) was used in four experimental huts within a large netting cage to allow mosquito recapture inside and outside of huts. Four treatments were evaluated: (1) new (12-month stored) ITS; (2) 12-month naturally-aged ITS; (3) 12-month field-used pyrethroid-PBO bednet (standard of care in Tanzania), and (4) no treatment. The study was performed for 32 nights using 30 mosquitoes per strain, per hut per night. Four laboratory-reared strains were used: malaria vectors (Anopheles arabiensis and An. funestus), dengue vector (Aedes aegypti), and nuisance biting (Culex quinquefasciatus). Recaptured mosquitoes were assessed for mortality at 72 h, blood-feeding, and hut entry. A simulation with a modified mechanistic model tracking Plasmodium falciparum malaria was used to illustrate potential epidemiological impact from these products. Against all mosquito species compared to 12-month aged pyrethroid-PBO-treated bednet, new ITS induced higher mortality [Odds Ratio:2.25(95%Confidence Interval:1.65-3.06),p < 0.0001], and aged-ITS was similar [OR:0.80(95%CI:0.59-1.08),p = 0.141]. Both new and aged ITS significantly (p < 0.0001) reduced mosquito blood-feeding [new OR:0.02(95% CI:0.01-0.03); aged OR:0.09(95%CI:0.05-0.14)] and hut entry [new IRR:0.10(95%CI:0.08-0.13); aged IRR:0.25(95%CI:0.21-0.31)]. Transmission model estimates indicate epidemiological impacts of ITS may supersede pyrethroid-PBO-treated bednets at the population level. The model results indicate impact potency depends on assumed intervention percentage cover, durability, and mosquito bionomics. This study introduces a standardised semi-field bioassay to evaluate ITS, generating entomological data that, for the first time, enabled modelling of its potential impact on malaria transmission. ITS is an efficacious tool for public health as it kills substantial proportions of malaria and dengue vectors, and reduces nuisance biting. Given its simplicity, it should be considered an additional or stand-alone tool for screening unimproved houses.
Rift Valley fever virus (RVFV) is endemic in sub-Saharan Africa and the Arabian Peninsula, primarily infecting ruminants such as sheep and cattle and causing high abortion and neonatal mortality rates. Previous studies have indicated hyperendemic circulation of RVFV in north-eastern KwaZulu-Natal (KZN), South Africa. The vectors of RVFV are not well characterized in this area, particularly with respect to species composition, seasonal abundance, and potential vector roles; however, several potential mosquito vector species have been identified. The aim of this study was to describe the species composition, abundance, and seasonal population dynamics of potential RVFV vectors in far north-eastern KZN, in order to identify likely important RVFV vectors in the area. Mosquitoes were sampled monthly at three sites (Namaneni, Mpala and Bumbe), for one-to-two nights per site over a period of 3 years (November 2019-November 2022). CO2-baited CDC Miniature Light Traps, operated without light, and CO2-baited tent traps (modified Shannon) were used at pans (temporary wetlands) at each site. Mosquitoes were morphologically identified using available taxonomic keys. A representative subset (approximately 40%) of collected mosquitoes, including potential primary and secondary vector species, were screened for RVFV RNA using real-time reverse transcription PCR. A total of 141,594 mosquitoes consisting of 46 species from 8 genera, including Aedes (2610), Culex (89,143), Mansonia (45,029), and others, were collected. Culex (Culex) tritaeniorhynchus (55,491), Mansonia (Mansonioides) uniformis (35,453), and Culex (Lasioconops) poicilipes (14,192) were the most common species, varying in their relative proportions between sites. Mosquito species diversity and abundance differed across sites, with seasonal peaks occurring from January to April. Overall counts were higher at Namaneni (IRR = 3.30, 95% CI 2.62-4.16), p < 0.001) but lower at Bumbe (IRR = 0.35, 95% CI 0.23-0.54, p < 0.001), compared to Mpala. All 55,113 screened mosquitoes tested negative for RVFV. Multiple potential RVFV vectors, such as Cx. tritaeniorhynchus, Cx. poicilipes, Aedes (Neomelaniconion) circumluteolus, Aedes (Neo.) mcintoshi, and Aedes (Aedimorphus) durbanensis, were found to be present in relatively high numbers and could play an important role in both endemic and epidemic RVFV transmission.
West Nile virus is an arbovirus transmitted by infected Culex mosquitoes to birds, horses, and humans. Since its first recorded case in Germany in 2018, WNV has been endemic in several parts of Germany. Globalization, ecosystem modification and climate change have been identified as significant drivers of the arbovirus spread. However, vertical transmission of pathogens from adult female to their progeny might alter the transmission dynamics. In this study, we designed a process-based epidemic model incorporating climatic variables and epidemiological parameters that replicated mosquito populations and pathogen transmission between mosquito vectors and hosts, explicitly accounting for the role of vertical transmission. In addition, we evaluated the efficiency of biological, chemical, and mechanical strategies for mosquito population control. Our findings revealed that while vertical transmission marginally influenced West Nile virus transmission, the impact was more pronounced in endemic regions, signaling a relationship between vertical transmission and West Nile virus persistence. Among control methods implemented, the biological control method performed optimally and emerged as the preferred method over mechanical and chemical methods, respectively. This model provides an understanding on the impact of vertical transmission in mosquito-borne disease epidemiology and provides insights into the efficiency of mosquito control strategies which would support optimized implementation of mosquito management programs.
Entomological surveillance provides critical information for National Malaria Programs (NMPs), yet there is limited evidence on the cost-effectiveness of alternative sampling approaches. Conventional surveillance often relies on purposive, fixed-site sampling, which may produce biased or non-representative data. To address these limitations, the Entomological Adaptive Sampling Framework (EASF) was developed to optimize sampling strategies based on spatiotemporal vector dynamics. This study evaluates the costs and cost-effectiveness of EASF compared to routine entomological surveillance in Ghana and Mozambique. We conducted a cost and cost-effectiveness analysis of EASF using prospective data from pilot implementations in Ghana (July 2023-2024) and Mozambique (September 2022-August 2024). Costs (in current US$) were estimated from a payer perspective through microcosting , categorized by input type and activity. Effectiveness was measured based on collection yields, namely the total number of mosquitoes collected and the average number of mosquitoes per collection. Incremental cost-effectiveness ratios (ICERs) were calculated to compare EASF with routine entomological surveillance. The total costs of EASF were $144,688 in Ghana (13 months) and $48,646 in Mozambique (9 months). EASF was associated with higher costs than routine surveillance ($90,004 in Ghana; $22,311 in Mozambique). On average, EASF was associated with 0.75 and 1.12 more mosquitoes per collection in Ghana and Mozambique, respectively. The unit cost of each mosquito collected was lower under EASF ($11.10 vs. $43.65 in Ghana; $54.23 vs. $743.69 in Mozambique). The ICERs of EASF were $4.98 and $30.38 per additional mosquito collected, and $30.23 and $72.76 per increase in the average number of mosquitoes per collection in Ghana and Mozambique, respectively. EASF has the potential to improve the efficiency of entomological surveillance by collecting more mosquitoes at lower costs. Future research should build on these findings by demonstrating the downstream value of improved entomological data on NMP decision-making and malaria transmission. A budget impact analysis should assess the affordability of scaling up EASF.