Episodes

  • AI for Culex Mosquito Identification using Wing Patterns (July 2025)
    Jul 1 2025
    Detailed Briefing Document: Application of Wing Interference Patterns (WIPs) and Deep Learning (DL) for Culex spp. ClassificationApplication of wings interferential patterns (WIPs) and deep learning (DL) to classify some Culex. spp (Culicidae) of medical or veterinary importanceArnaud Cannet, Camille Simon Chane, Aymeric Histace, Mohammad Akhoundi, Olivier Romain, Pierre Jacob, Darian Sereno, Marc Souchaud, Philippe Bousses & Denis Sereno Scientific Reports volume 15, Article number: 21548 (2025)Source: https://doi.org/10.1038/s41598-025-08667-yReceived - 28 November 2024 | Accepted - 23 June 2025 | Published - 01 July 2025This briefing document reviews a study that successfully demonstrates the utility of combining Wing Interference Patterns (WIPs) with deep learning (DL) models for the accurate identification of Culex mosquito species. Culex mosquitoes are significant vectors for numerous arboviruses and parasites of medical and veterinary importance, including West Nile virus, Japanese encephalitis, Saint Louis encephalitis, and lymphatic filariasis. Traditional morphological identification methods are labor-intensive, prone to errors due to cryptic species or damaged samples, and often yield variable accuracy (e.g., ~64% average species-level accuracy in external assessments).The research team developed a method leveraging the unique, stable interference patterns visible on transparent insect wing membranes (WIPs) as species-specific morphological markers. By integrating these WIPs with Convolutional Neural Networks (CNNs), the study achieved over 95% genus-level accuracy for Culex and up to 100% species-level accuracy for certain species. While challenges remain with underrepresented species in the dataset, this approach presents a scalable, cost-effective, and robust alternative or complement to traditional identification methods, with significant potential for enhancing vector surveillance and global health initiatives.Key Themes and Important Ideas/Facts1. The Challenge of Mosquito Identification and its ImportanceGlobal Health Threat: Arthropod-transmitted pathogens, including viruses, bacteria, and parasites, are "among the most destructive infectious agents globally."Vector Role of Culex: The Culex genus, comprising over 783 recognized species and 55 subspecies, "are recognized vectors of significant diseases, such as West Nile virus fever, Japanese encephalitis, Saint Louis encephalitis, or lymphatic filariasis."Difficulty of Traditional Methods: "Traditional morphological identification is labor-intensive and relies on diagnostic features and determination keys." This method is "often challenged by cryptic species, overlapping morphological traits, and damaged specimens."Need for Innovation: These limitations "emphasize the need for innovative identification methods to enhance entomological surveys."2. Wing Interference Patterns (WIPs) as Species-Specific MarkersNature of WIPs: WIPs are "visible color patterns caused by thin-film interference" on the thin, transparent wing membranes of insects, particularly smaller species. They become visible when wings are "illuminated in a dark, light-absorbing setting."Species-Specific Consistency: "These Wing Interference Patterns (WIPs) show substantial variation between different species, while remaining relatively consistent within a species or between sexes."Stability of WIPs: Unlike conventional iridescence, the "microstructure of insect wings functions as a dioptric system that stabilizes the interference pattern, making WIPs largely insensitive to viewing angle."Potential as Morphological Markers: Due to their "species-specific consistency and interspecific variability, WIPs hold strong potential as morphological markers for insect classification, offering a promising alternative or complement to traditional taxonomic traits."3. Integration of WIPs with Deep Learning (DL) for ClassificationPrevious Successes: WIPs and DL have previously "successfully demonstrated their utility in identifying Anopheles, Aedes, sandflies, and tsetse flies." This study extends the approach to Culex.Methodology: The study applied "WIPs, generated by thin-film interference on wing membranes, in combination with convolutional neural networks (CNNs) for species classification."CNN Advantages: Deep Convolutional Neural Networks (CNNs) are "most effective for image classification" and "automatically selects the optimal features during the learning process, making it particularly suitable for WIP classification tasks."Dataset: The study used a refined dataset of "553 images representing WIPs from 7 species" for training, with a larger database including "572 images of 12 species across 5 subgenera" for general classification and 4,944 images of non-Culex Diptera as negative controls.4. Classification Performance and ResultsHigh Genus-Level Accuracy: The CNN achieved "genus-level classification accuracy exceeding 95.00%."Variable Species-Level Accuracy: "At the species ...
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    16 mins
  • Greenland Mosquito Virome: Arctic Aedes Uniqueness (May 2025)
    May 30 2025
    Briefing Document: Unique Virome of Arctic Mosquitoes in GreenlandSource: https://doi.org/10.1038/s41598-025-01086-z: "Metagenomic analysis of mosquitoes from Kangerlussuaq, Greenland reveals a unique virome" by Schilling, Jagdev, Thomas, & Johnson (2025). Date: Received - 17 January 2025 | Accepted - 02 May 2025 | Published - 17 May 2025Subject: Metagenomic analysis of mosquito viromes in Kangerlussuaq, Greenland and implications in the context of climate change.Summary: This study provides the first metagenomic analysis of the virome of two prevalent Arctic mosquito species, Aedes impiger and Aedes nigripes, sampled near Kangerlussuaq, Greenland. The research employed next-generation sequencing (NGS) to identify viruses present in pooled mosquito samples collected in July 2022 and July 2023. The findings reveal a diverse and, importantly, a unique virome in these Arctic mosquitoes compared to other Aedes species. The study highlights the critical need to understand these viromes in light of climate change, which is significantly impacting Arctic ecosystems and potentially increasing the risk of vector-borne disease emergence and spread.Key Findings and Themes:Dominance of Aedes impiger: Contrary to previous assumptions that Aedes nigripes was the sole mosquito species in western Greenland, this study found Aedes impiger to be the predominant species collected at the Kangerlussuaq site.Fact: "Where a definitive identification could be made, A. impiger was the most frequently sampled mosquito at the Kangerlussuaq site."Fact: In 2023, "49 mosquitoes were identified as A. impiger (70%) and 16 as A. nigripes (23%)."Novel and Diverse Arctic Mosquito Virome: Metagenomic analysis identified a range of RNA viruses belonging to various families in both Aedes impiger and Aedes nigripes. Many of these viruses are novel and exhibit low sequence identity (sometimes as low as 34% at the amino acid level) when compared to previously published virus sequences from other mosquito species.Quote: "Metagenomic analysis of RNA extracted from species pools detected a number of novel RNA viruses belonging to a range of different virus families, including Flaviviridae, Orthomyxoviridae, Bunyavirales, Totiviridae and Rhabdoviridae."Quote: "However, the sequence identities when compared to previously published, were as low as 34% at the amino acid level."Fact: "Within the family of Flaviviridae, two novel flavi-like virus sequences were identified, with their polyproteins displaying 35% similarity to the nearest published polyprotein..."Fact: "Similarly, two novel orthomyxo-like sequences were identified within the family of Orthomoyxoviridae... Their nucleoprotein comprised only 36% identity to that of Byreska virus..."Fact: "Within the order of Bunyavirales, we discovered two novel phasiviruses as well as two novel phasmaviruses."Uniqueness of the Arctic Mosquito Virome: A significant finding is the distinct virome of Aedes impiger and Aedes nigripes compared to other Aedes species, particularly Aedes aegypti, which has the most well-characterized virome. Only a small percentage of the identified viruses overlapped with those found in other Aedes species.Quote: "To emphasize the uniqueness of the virome of A. impiger and A. nigripes, we compared our findings to a database of viruses published for other Aedes species... The heatmap... reveals that the majority of sequences derived from Greenland mosquitoes were unique to A. impiger and A. nigripes..."Fact: "...only 36 (of a total of 94, 38%) assigned viruses overlapping with viruses published for other Aedes spp."Fact: "Only 22 (23%) overlapped with Aedes aegypti..."Quote: "This makes the virome composition of A. cantans the most similar published virome composition to that of the mosquitoes we sampled near Kangerlussuaq."Influence of Climate Change on Arctic Vector Ecology: The study explicitly links its findings to the dramatic effects of climate change on Arctic ecosystems, including the potential for shifts in vector distribution and an increased likelihood of vector-borne disease emergence in previously unaffected areas.Quote: "Climate change is dramatically affecting vector ecology in extreme environments such as the Arctic."Quote: "Global changes in climate are causing a shift in the distribution of vectors and increasing the likelihood of vector-borne disease outbreaks in regions that have not experienced such disease emergence."Quote: "With rapid environmental change, and warming at twice the global average the ecology of Arctic insects will be dramatically affected."Potential for Zoonotic Transmission Risk: While the detected viruses are likely insect-specific, the study highlights the potential for Aedes impiger and Aedes nigripes to replicate viruses belonging to families with known zoonotic potential. The documented human feeding behavior of Aedes impiger further underscores this risk.Quote: "Our findings further support the capability of A. nigripes and A. ...
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    21 mins
  • Novel Quinolones Counteract Insecticide Resistance in Malaria Vectors (May 2025)
    May 30 2025
    BRIEFING DOCUMENT: Novel Approach to Malaria Control Targeting Mosquito-Stage Plasmodium ParasitesDate: Received - 29 March 2025 | Accepted - 17 April 2025 | Published - 21 May 2025Source: Excerpts from "In vivo screen of Plasmodium targets for mosquito-based malaria control" by Probst et al. (Published online xx xx xxxx, Nature) https://doi.org/10.1038/s41586-025-09039-2Subject: Development and testing of novel antiparasitic compounds for incorporation into mosquito bed nets to combat insecticide resistance and reduce malaria transmission.Summary:This research presents a promising new strategy for malaria control by targeting the Plasmodium falciparum parasite directly within its mosquito vector (Anopheles species). Recognizing the growing challenge of insecticide resistance in mosquitoes, the study explores the potential of incorporating antiparasitic compounds into long-lasting insecticide-treated nets (LLINs). The authors performed an in vivo screen of 81 compounds, identifying 22 active against mosquito-stage parasites. Notably, endochin-like quinolones (ELQs) targeting the parasite's cytochrome bc1 complex (CytB) showed high potency and were further optimized through medicinal chemistry. Two lead ELQ compounds, ELQ-453 and ELQ-613, demonstrated potent, long-lasting activity when incorporated into bed net-like materials, including in insecticide-resistant mosquitoes. The study also highlights the potential of a dual-target strategy using a combination of Qo-site and Qi-site ELQ inhibitors to reduce the risk of resistance, as CytB mutants show impaired development in mosquitoes. This approach offers a complementary tool to existing malaria control strategies, particularly in areas with high insecticide resistance.Key Themes and Important Ideas/Facts:Malaria Burden and the Challenge of Insecticide Resistance:Malaria deaths have stalled in recent years, with an estimated 263 million cases and 597,000 deaths in 2023.Vector control, particularly LLINs, has been crucial in reducing malaria prevalence, but widespread insecticide resistance in Anopheles vectors is jeopardizing their effectiveness."The decline in malaria deaths has recently stalled owing to several factors, including the widespread resistance of Anopheles vectors to the insecticides used in long-lasting insecticide-treated nets (LLINs)..."Targeting Mosquito-Stage Parasites as a Mitigation Strategy:Directly killing parasites during their mosquito-stage development by incorporating antiparasitic compounds into LLINs can prevent onward transmission, even if insecticides lose efficacy.This strategy avoids conferring fitness costs or selective pressure on the mosquito, thus preventing vector resistance to the antiparasitic compound."Interventions that directly target parasites in the mosquito represent a promising approach to disrupt parasite transmission and to reduce malaria burden...""Of note, the use of a Plasmodium-specific compound would not confer any fitness cost or selective pressure to the anopheline mosquito, which therefore avoids potential development of resistance by the vector."In Vivo Compound Screening and Identification of Key Targets:An in vivo screen of 81 antiplasmodial compounds with diverse modes of action was performed in Anopheles gambiae mosquitoes.22 compounds spanning seven distinct P. falciparum targets significantly reduced parasite infection (oocyst prevalence) in the mosquito midgut.Key identified targets included the ubiquinol oxidation (Qo) and ubiquinone reduction (Qi) sites of the P. falciparum cytochrome bc1 complex (CytB), the sodium-proton antiporter P-type ATPase 4 (ATP4), and eukaryotic elongation factor 2 (EF2)."This screen ultimately identified 22 compounds that significantly reduced parasite infection, and these compounds spanned seven P. falciparum targets..."Endochin-Like Quinolones (ELQs) as Lead Compounds:Endochin-like quinolones (ELQs) targeting CytB were among the most effective compounds in the topical screen.ELQ-456 (targeting the CytB Qo-site) completely inhibited infection in topical applications.ELQ-331 (targeting the CytB Qi-site) strongly reduced infection prevalence.Medicinal chemistry was used to improve the antiparasitic activity of ELQ hits, particularly for uptake via tarsal contact (mosquito legs).Tarsal Contact Activity and the Importance of Compound Structure:Tarsal contact assays, mimicking mosquito interaction with treated surfaces like bed nets, showed that most compounds active in topical application were inactive.Only ELQ-456 initially showed significant activity in tarsal contact assays.Modifications to the ELQ structure significantly enhanced tarsal-based efficacy. ELQ-453 (Qo-site inhibitor) and ELQ-613 (Qi-site inhibitor), with specific alkyl chain lengths, demonstrated potent activity after tarsal contact."Of the 13 compounds we tested in tarsal-contact assays, only our most potent hit in the topical screen, ELQ-456 (CytB Qo-site inhibitor) reduced infection (69.5% ...
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    25 mins
  • Blocking Malaria Transmission with PfPIMMS43 Nanobodies (April 2025)
    May 3 2025
    Briefing Document: Nanobody-Mediated Blocking of Malaria Transmission Targeting PfPIMMS43Source: Excerpts from "s42003-025-08033-8.pdf" (A Nature Portfolio journal; https://doi.org/10.1038/s42003-025-08033-8) Authors: Chiamaka Valerie Ukegbu, et al. Date: Received - 04 December 2024 | Accepted - 02 April 2025 | Published - 30 April 2025Executive Summary:This study explores a novel strategy to block malaria transmission by targeting the Plasmodium falciparum protein PfPIMMS43 using single-domain VHH antibodies, also known as nanobodies. PfPIMMS43 is a critical surface protein for the parasite's development within the mosquito, specifically during the transition from ookinete to oocyst, and aids in evading the mosquito's immune response. Building on previous research demonstrating the potential of polyclonal antibodies against PfPIMMS43, this study successfully developed and characterized high-affinity nanobodies derived from llamas. These nanobodies were shown to significantly reduce both the intensity and prevalence of P. falciparum infection in Anopheles mosquitoes using both laboratory and field strains of the parasite. The study mapped the binding epitopes of the nanobodies to conserved regions in the second half of PfPIMMS43, confirming epitope accessibility. These findings establish PfPIMMS43 as a promising target for malaria transmission-blocking interventions and propose an innovative strategy utilizing genetically modified mosquitoes expressing these nanobodies in conjunction with gene drive technology for enhanced malaria control and elimination efforts.Key Themes and Important Ideas:Malaria Transmission as a Target: The study emphasizes the importance of targeting the parasite's development within the mosquito vector to interrupt the human-to-mosquito and mosquito-to-human transmission cycle. This is presented as a crucial approach to complement existing malaria control measures, especially in the face of challenges like insecticide failure, climate change, and funding limitations. The transition from ookinete to oocyst in the mosquito midgut is identified as a "key developmental bottleneck" for the parasite.PfPIMMS43 as a Critical Transmission Target: The research highlights PfPIMMS43 as an "indispensable" surface protein for P. falciparum ookinetes and sporozoites. It is crucial for the ookinete-to-oocyst transition and plays a role in the parasite's ability to "evade the mosquito immune responses," specifically the complement-like system in the hemolymph. Previous studies, including those by the authors, had already indicated the potential of polyclonal antibodies targeting this protein in reducing transmission.Nanobodies as a Promising Intervention Tool: The study focuses on the development and application of VHH domain nanobodies as an alternative and potentially superior approach to conventional antibodies for transmission blocking. Nanobodies, derived from camelids and sharks, are described as "smaller, more easily produced monoclonal, heavy-chain variable (VHH) domain antibodies." Their advantages include:"small size (~15 kDa)""structural simplicity""strong binding affinity"Easily bioengineered for targeting parasite antigens in mosquito vectors.Development and Characterization of PfPIMMS43 Nanobodies: High-affinity nanobodies targeting PfPIMMS43 were successfully generated by immunizing llamas with recombinant PfPIMMS43. Nine nanobodies were selected based on variations in their antigen-binding regions (CDR1-3). Four nanobodies (G9, E5, C12, and E2) exhibited high nanomolar binding affinities to recombinant PfPIMMS43 (3, 5, 6, and 8 nM, respectively). These four nanobodies were also able to detect endogenous PfPIMMS43 protein expressed by P. falciparum ookinetes in infected mosquito midguts.Significant Transmission Blocking Activity (TRA): The developed nanobodies demonstrated significant transmission-reducing activity in mosquito feeding assays.In standard membrane feeding assays (SMFAs) using laboratory P. falciparum NF54 and An. coluzzii mosquitoes, the four high-affinity nanobodies (G9, E5, C12, and E2) significantly reduced oocyst numbers at a concentration of 100 µg/ml, with reductions ranging from 83% to 99%. Oocyst reduction was concentration-dependent.In direct membrane feeding assays (DMFAs) using natural P. falciparum isolates from gametocytaemic children in Tanzania and local An. gambiae mosquitoes, G9 and E5 (the two nanobodies with the highest affinities to recombinant PfPIMMS43) also showed significant TRA, with reductions of 99% and 79% at 100 µg/ml, respectively. Both nanobodies significantly reduced mosquito infection prevalence in field conditions.Epitope Mapping and Structural Insights: Epitope mapping revealed that the four nanobodies bind to "conserved regions in the second half of PfPIMMS43," specifically beyond amino acid residue 258. This suggests the C-terminal half of the protein is more immunogenic. G9 and E5 appear to recognize similar conformational ...
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    13 mins
  • Predicting Aedes Albopictus Spread in Europe via Climate and Population (April 2025)
    Apr 11 2025
    Population Dependent Diffusion Model for Aedes Albopictus Spread in EuropeSource: Barman et al., "A climate and population dependent diffusion model forecasts the spread of Aedes Albopictus mosquitoes in Europe," Nature Portfolio journal, 2025, https://doi.org/10.1038/s43247-025-02199-zDate: Received - 25 November 2024 | Accepted - 07 March 2025 | Published - 09 April 2025Key Themes and Important Ideas/Facts:This paper presents a novel spatio-temporal diffusion model that accurately forecasts the spread of Aedes albopictus mosquitoes in Europe by simultaneously considering climate suitability and human population factors. Ae. albopictus is a crucial vector for several arboviruses, including Dengue, Chikungunya, Zika, and Yellow Fever. The study highlights the increasing risk of autochthonous (local) transmission of these diseases in Europe due to the mosquito's expanding range, driven by environmental changes and global interconnectedness.1. Predictable Spread of Ae. albopictus:The core finding is that the expansion of Ae. albopictus in Europe is predictable by integrating climate suitability and human population predictors within a single spatio-temporal diffusion model.The model demonstrates high accuracy in predicting areas of presence and absence (99% and 79% respectively).This predictability allows for anticipating future outbreaks by understanding the interplay between vector suitability and introduction.Quote: "These results show that the expansion of Ae. albopictus in Europe is predictable and provide a basis for anticipating future outbreaks in situations of dependent interacting co-drivers."2. Drivers of Ae. albopictus Expansion:The study confirms that climate change (suitable climatic conditions), urbanization, and human population mobility are key factors facilitating the invasion of new habitats by this species.Quote: "Suitable climatic conditions favoured by climate change, urbanisation, and human populationmobility, seems to have facilitated the expansion of this invasive mosquito species into novel habitats."The passive transport of eggs through global travel and trade (e.g., used tires, lucky bamboo) and ground vehicles contributes significantly to its spread along transportation corridors.The mosquito's ecological and physiological plasticity (e.g., adaptation to cold, desiccation-resistant eggs, domestic container-breeding) enables its rapid and widespread expansion.3. Model Development and Performance:The researchers developed a "highly predictive spatio-temporal vector diffusion model" that integrates climate suitability (temperature, humidity) and human population data.The model is a generalized additive mixed (GAM) model fitted within a Bayesian framework (INLA).It accounts for both short-range spread (geographical proximity) and potential long-range spread influenced by human population.The model demonstrates good overall performance, with AUC values around 0.80 for predicting new establishments in previously uncolonized areas.Quote: "Notably, model evaluation reveals that new introduction of Ae. albopictus into naïve areas, are very well predicted, which has not been achieved before with this type of model."Two versions of the model were calibrated: one using raw climate and population covariates, and another using a mechanistic mosquito life cycle model output as a covariate. Both showed similar predictive performance.4. Key Covariates and Their Influence:Temperature: Median temperature (up to 24°C) shows a strong positive correlation with Ae. albopictus presence, decreasing at higher temperatures. Minimum temperature is positively correlated when median temperatures are high.Relative Humidity: Low relative humidity is negatively correlated with Ae. albopictus presence.Proximity: Geographical proximity to already established areas has a substantial impact on the spread, modeled through a spatio-temporal diffusion process.Human Population: Higher population density is associated with a higher likelihood of Ae. albopictus presence, likely reflecting increased introduction opportunities via human mobility, although the measured effect size was relatively small compared to climate factors.Human mobility modeled explicitly using a radiation model did not significantly improve model fit, suggesting that local diffusion and the human population covariate together can effectively capture its impact.5. Implications for Public Health:The model can be a valuable tool for preparedness and response to Aedes-borne infections by identifying high-risk areas for new introductions.Quote: "This model can be integrated into early warning systems and help delineate areas at risk for the introduction and establishment of Ae. albo-pictus."Predictions can help target awareness and prevention messages to susceptible populations and guide vector control efforts.The model can also inform healthcare system preparedness for potential epidemics and the strategic deployment of available arboviral vaccines...
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    13 mins