Host preference patterns in domestic and wild settings: Insights into Anopheles feeding behavior.

The adaptation of Anopheles malaria vectors to domestic settings is directly linked to their ability to feed on humans. The strength of this species-habitat association is unequal across the species within the genus, with the major vectors being particularly dependent on humans. However, our understanding of how blood-feeding behavior interacts with and adapts to environmental settings, including the presence of humans, remains limited. Using a field-based approach, we first investigated Anopheles community structure and feeding behavior patterns in domestic and sylvatic settings in La Lopé National Park in Gabon, Central Africa. We characterized the preference indices using a dual-host choice sampling approach across mosquito species, habitats, and seasons. We then quantified the plastic biting behavior of mosquito species in each habitat. We collected individuals from 16 Anopheles species that exhibited significant differences in species composition and abundance between sylvatic and domestic settings. The host-seeking behavior also varied among the seven most abundant species. The general attractiveness to each host, human or animal, remained relatively constant for each species, but with significant variations between habitats across species. These variations, to more generalist and to more anthropophilic behavior, were related to seasonal changes and distance from the village, respectively. Finally, we pointed out that the host choice of major malaria vectors changed in the absence of humans, revealing a plastic feeding behavior of these species. This study highlights the effect of humans on Anopheles distribution and feeding evolution. The characterization of feeding behavior in wild and domestic settings provides opportunities to better understand the interplay between genetic determinants of host preference and ecological factors. Our findings suggest that protected areas may offer alternative thriving conditions to major malaria vectors.

Global genomics of Aedes aegypti unveils widespread and novel infectious viruses capable of triggering a small RNA response.

The mosquito Aedes aegypti is a prominent vector for arboviruses, but the breadth of mosquito viruses that infects this specie is not fully understood. In the broadest global survey to date of over 200 Ae. aegypti small RNA samples, we detected viral small interfering RNAs (siRNAs) and Piwi interacting RNAs (piRNAs) arising from mosquito viruses. We confirmed that most academic laboratory colonies of Ae. aegypti lack persisting viruses, yet two commercial strains were infected by a novel tombus-like virus. Ae. aegypti from North to South American locations were also teeming with multiple insect viruses, with Anphevirus and a bunyavirus displaying geographical boundaries from the viral small RNA patterns. Asian Ae. aegypti small RNA patterns indicate infections by similar mosquito viruses from the Americas and reveal the first wild example of dengue virus infection generating viral small RNAs. African Ae. aegypti also contained various viral small RNAs including novel viruses only found in these African substrains. Intriguingly, viral long RNA patterns can differ from small RNA patterns, indicative of viral transcripts evading the mosquitoes' RNA interference (RNAi) machinery. To determine whether the viruses we discovered via small RNA sequencing were replicating and transmissible, we infected C6/36 and Aag2 cells with Ae. aegypti homogenates. Through blind passaging, we generated cell lines stably infected by these mosquito viruses which then generated abundant viral siRNAs and piRNAs that resemble the native mosquito viral small RNA patterns. This mosquito small RNA genomics approach augments surveillance approaches for emerging infectious diseases.

Practical considerations relevant to treatment with the gene therapy beremagene geperpavec-svdt for dystrophic epidermolysis bullosa.

BACKGROUND/PURPOSE: Dystrophic epidermolysis bullosa (DEB), a rare genetic skin disease caused by loss-of-function mutations in COL7A1, the gene encoding type VII collagen (COL7), is characterized by skin blistering, scarring, and extracutaneous manifestations that markedly reduce patient quality-of-life. Beremagene geperpavec-svdt ('B-VEC') is a gene therapy employing a non-integrating, replication-defective herpes simplex virus type 1 (HSV-1)-based vector encoding two copies of full-length human COL7A1 to restore COL7 protein after topical administration to DEB wounds. B-VEC was approved in the United States in 2023 as the first topical gene therapy and the first approved treatment for DEB. However, few providers have experience with use of this gene therapy. METHODS: Data was obtained through literature review and the experience of providers who participated in the B-VEC clinical study or initiated treatment after B-VEC approval. RESULTS: This review discusses the burden of disease, describes the clinical trial outcomes of B-VEC, and provides physician and patient/caregiver recommendations as a practical guide for the real-world use of B-VEC, which can be administered in-office or at the patient's home. CONCLUSIONS: By continuing to optimize the practical aspects of B-VEC administration, the focus will continue to shift to patient-centric considerations and improved patient outcomes.

Genomic Signatures of Microgeographic Adaptation in Anopheles coluzzii Along an Anthropogenic Gradient in Gabon.

Species distributed across heterogeneous environments often evolve locally adapted populations, but understanding how these persist in the presence of homogenizing gene flow remains puzzling. In Gabon, Anopheles coluzzii, a major African malaria mosquito is found along an ecological gradient, including a sylvatic population, away of any human presence. This study identifies into the genomic signatures of local adaptation in populations from distinct environments including the urban area of Libreville, and two proximate sites 10km apart in the La Lopé National Park (LLP), a village and its sylvatic neighborhood. Whole genome re-sequencing of 96 mosquitoes unveiled ∼ 5.7millions high-quality single nucleotide polymorphisms. Coalescent-based demographic analyses suggest an ∼ 8,000-year-old divergence between Libreville and La Lopé populations, followed by a secondary contact ( ∼ 4,000 ybp) resulting in asymmetric effective gene flow. The urban population displayed reduced effective size, evidence of inbreeding, and strong selection pressures for adaptation to urban settings, as suggested by the hard selective sweeps associated with genes involved in detoxification and insecticide resistance. In contrast, the two geographically proximate LLP populations showed larger effective sizes, and distinctive genomic differences in selective signals, notably soft-selective sweeps on the standing genetic variation. Although neutral loci and chromosomal inversions failed to discriminate between LLP populations, our findings support that microgeographic adaptation can swiftly emerge through selection on standing genetic variation despite high gene flow. This study contributes to the growing understanding of evolution of populations in heterogeneous environments amid ongoing gene flow and how major malaria mosquitoes adapt to human. Significance: Anopheles coluzzii , a major African malaria vector, thrives from humid rainforests to dry savannahs and coastal areas. This ecological success is linked to its close association with domestic settings, with human playing significant roles in driving the recent urban evolution of this mosquito. Our research explores the assumption that these mosquitoes are strictly dependent on human habitats, by conducting whole-genome sequencing on An. coluzzii specimens from urban, rural, and sylvatic sites in Gabon. We found that urban mosquitoes show de novo genetic signatures of human-driven vector control, while rural and sylvatic mosquitoes exhibit distinctive genetic evidence of local adaptations derived from standing genetic variation. Understanding adaptation mechanisms of this mosquito is therefore crucial to predict evolution of vector control strategies.

Extensive variation and strain-specificity in dengue virus susceptibility among African Aedes aegypti populations.

African populations of the mosquito Aedes aegypti are usually considered less susceptible to infection by human-pathogenic flaviviruses than globally invasive populations found outside Africa. Although this contrast has been well documented for Zika virus (ZIKV), it is unclear to what extent it is true for dengue virus (DENV), the most prevalent flavivirus of humans. Addressing this question is complicated by substantial genetic diversity among DENV strains, most notably in the form of four genetic types (DENV1 to DENV4), that can lead to genetically specific interactions with mosquito populations. Here, we carried out a survey of DENV susceptibility using a panel of seven field-derived Ae. aegypti colonies from across the African range of the species and a colony from Guadeloupe, French West Indies as non-African reference. We found considerable variation in the ability of African Ae. aegypti populations to acquire and replicate a panel of six DENV strains spanning the four DENV types. Although African Ae. aegypti populations were generally less susceptible than the reference non-African population from Guadeloupe, in several instances some African populations were equally or more susceptible than the Guadeloupe population. Moreover, the relative level of susceptibility between African mosquito populations depended on the DENV strain, indicating genetically specific interactions. We conclude that unlike ZIKV susceptibility, there is no clear-cut dichotomy in DENV susceptibility between African and non-African Ae. aegypti. DENV susceptibility of African Ae. aegypti populations is highly heterogeneous and largely governed by the specific pairing of mosquito population and DENV strain.

ULTRAPETALAs in action: Unraveling their role in root development.

The epigenetic complex Trithorax (TrxG) regulates gene transcription through post-translational histone modifications and is involved in a wide range of developmental processes. ULTRAPETALA1 (ULT1) is a SAND domain plant-exclusive TrxG protein that regulates the H3K4me3 active mark to counteract PcG repression. ULT1 has been identified to be involved in multiple tissue-specific processes. In the Arabidopsis root, ULT1 is required to maintain the stem cell niche, a role that is independent of the histone methyltransferase ATX1. Here we show the contribution of ULT2 in the maintenance of root stem cell niche. We also analyzed the gene expression in the ult1, ult2, and ult1ult2 mutants, evidencing three ways in which ULT1 and ULT2 regulate gene expression, one of them, where ULT1 or ULT2 regulate specific genes each, another where ULT1 and ULT2 act redundantly, as well as a regulation that requires of ULT1 and ULT2 together, supporting a coregulation, never reported. Furthermore, we also evidenced the participation of ULT1 in transcriptional repression synergically with CLF, a key histone methyltransferase of PcG.

A chromosomal reference genome sequence for the malaria mosquito, Anopheles moucheti, Evans, 1925.

We present a genome assembly from an individual male Anopheles moucheti (the malaria mosquito; Arthropoda; Insecta; Diptera; Culicidae), from a wild population in Cameroon. The genome sequence is 271 megabases in span. The majority of the assembly is scaffolded into three chromosomal pseudomolecules with the X sex chromosome assembled. The complete mitochondrial genome was also assembled and is 15.5 kilobases in length.

Limited association between Wolbachia and Plasmodium falciparum infections in natural populations of the major malaria mosquito Anopheles moucheti.

Since the discovery of natural malaria vector populations infected by the endosymbiont bacterium Wolbachia, a renewed interest has arisen for using this bacterium as an alternative for malaria control. Among naturally infected mosquitoes, Anopheles moucheti, a major malaria mosquito in Central Africa, exhibits one of the highest prevalences of Wolbachia infection. To better understand whether this maternally inherited bacterium could be used for malaria control, we investigated Wolbachia influence in An. moucheti populations naturally infected by the malaria parasite Plasmodium falciparum. To this end, we collected mosquitoes in a village from Cameroon, Central Africa, where this mosquito is the main malaria vector. We found that the prevalence of Wolbachia bacterium was almost fixed in the studied mosquito population, and was higher than previously recorded. We also quantified Wolbachia in whole mosquitoes and dissected abdomens, confirming that the bacterium is also elsewhere than in the abdomen, but at lower density. Finally, we analyzed the association of Wolbachia presence and density on P. falciparum infection. Wolbachia density was slightly higher in mosquitoes infected with the malaria parasite than in uninfected mosquitoes. However, we observed no correlation between the P. falciparum and Wolbachia densities. In conclusion, our study indicates that naturally occurring Wolbachia infection is not associated to P. falciparum development within An. moucheti mosquitoes.

Age-Specific Demographic Response of a Long-Lived Scavenger Species to Reduction of Organic Matter in a Landfill.

Food availability shapes demographic parameters and population dynamics. Certain species have adapted to predictable anthropogenic food resources like landfills. However, abrupt shifts in food availability can negatively impact such populations. While changes in survival are expected, the age-related effects remain poorly understood, particularly in long-lived scavenger species. We investigated the age-specific demographic response of a Griffon vulture (Gyps fulvus) population to a reduction in organic matter in a landfill and analyzed apparent survival and the probability of transience after initial capture using a Bayesian Cormack-Jolly-Seber model on data from 2012-2022. The proportion of transients among newly captured immatures and adults increased after the reduction in food. Juvenile apparent survival declined, increased in immature residents, and decreased in adult residents. These results suggest that there was a greater likelihood of permanent emigration due to intensified intraspecific competition following the reduction in food. Interestingly, resident immatures showed the opposite trend, suggesting the persistence of high-quality individuals despite the food scarcity. Although the reasons behind the reduced apparent survival of resident adults in the final four years of the study remain unclear, non-natural mortality potentially plays a part. In Europe landfill closure regulations are being implemented and pose a threat to avian scavenger populations, which underlines the need for research on food scarcity scenarios and proper conservation measures.

Towards the invasion of wild and rural forested areas in Gabon (Central Africa) by the Asian tiger mosquito Aedes albopictus: Potential risks from the one health perspective.

BACKGROUND: Since its first record in urban areas of Central-Africa in the 2000s, the invasive mosquito, Aedes albopictus, has spread throughout the region, including in remote villages in forested areas, causing outbreaks of Aedes-borne diseases, such as dengue and chikungunya. Such invasion might enhance Ae. albopictus interactions with wild animals in forest ecosystems and favor the spillover of zoonotic arboviruses to humans. The aim of this study was to monitor Ae. albopictus spread in the wildlife reserve of La Lopé National Park (Gabon), and evaluate the magnitude of the rainforest ecosystem colonization. METHODOLOGY: From 2014 to 2018, we used ovitraps, larval surveys, BG-Sentinel traps, and human landing catches along an anthropization gradient from La Lopé village to the natural forest in the Park. CONCLUSIONS: We detected Ae. albopictus in gallery forest up to 15 km away from La Lopé village. However, Ae. albopictus was significantly more abundant at anthropogenic sites than in less anthropized areas. The number of eggs laid by Ae. albopictus decreased progressively with the distance from the forest fringe up to 200m inside the forest. Our results suggested that in forest ecosystems, high Ae. albopictus density is mainly observed at interfaces between anthropized and natural forested environments. Additionally, our data suggested that Ae. albopictus may act as a bridge vector of zoonotic pathogens between wild and anthropogenic compartments.

Invasive hematophagous arthropods and associated diseases in a changing world.

Biological invasions have increased significantly with the tremendous growth of international trade and transport. Hematophagous arthropods can be vectors of infectious and potentially lethal pathogens and parasites, thus constituting a growing threat to humans-especially when associated with biological invasions. Today, several major vector-borne diseases, currently described as emerging or re-emerging, are expanding in a world dominated by climate change, land-use change and intensive transportation of humans and goods. In this review, we retrace the historical trajectory of these invasions to better understand their ecological, physiological and genetic drivers and their impacts on ecosystems and human health. We also discuss arthropod management strategies to mitigate future risks by harnessing ecology, public health, economics and social-ethnological considerations. Trade and transport of goods and materials, including vertebrate introductions and worn tires, have historically been important introduction pathways for the most prominent invasive hematophagous arthropods, but sources and pathways are likely to diversify with future globalization. Burgeoning urbanization, climate change and the urban heat island effect are likely to interact to favor invasive hematophagous arthropods and the diseases they can vector. To mitigate future invasions of hematophagous arthropods and novel disease outbreaks, stronger preventative monitoring and transboundary surveillance measures are urgently required. Proactive approaches, such as the use of monitoring and increased engagement in citizen science, would reduce epidemiological and ecological risks and could save millions of lives and billions of dollars spent on arthropod control and disease management. Last, our capacities to manage invasive hematophagous arthropods in a sustainable way for worldwide ecosystems can be improved by promoting interactions among experts of the health sector, stakeholders in environmental issues and policymakers (e.g. the One Health approach) while considering wider social perceptions.

Establishing Colonies from Field-Collected Mosquitoes: Special Accommodations for Wild Strains.

A researcher may have many reasons for wanting to establish new laboratory colonies from field-collected mosquitoes. In particular, the ability to study the diversity found within and among natural populations in a controlled laboratory environment opens up a wide range of possibilities for understanding how and why burdens of vector-borne disease vary over space and time. However, field-collected mosquitoes are often more difficult to work with than established laboratory strains, and considerable logistical challenges are involved in safely transporting field-collected mosquitoes into the laboratory. Here, we provide advice for researchers working with Aedes aegypti, Anopheles gambiae, and Culex pipiens, as well as notes on other closely related species. We provide guidance on each stage of the life cycle and highlight the life stages for which it is easiest to initiate new laboratory colonies for each species. In accompanying protocols, we provide methods detailing Ae. aegypti egg collection and hatching as well as how to transport larvae and pupae from the field.

Collecting, Storing, and Hatching Aedes aegypti Eggs.

Laboratory study of natural populations of mosquitoes can play a key role in determining the underlying causes of variation in burdens of mosquito-borne disease. Aedes aegypti is the main vector of the viruses that cause dengue, chikungunya, Zika, and yellow fever, making it a high priority for laboratory study. Ae. aegypti eggs provide an ideal starting point for new laboratory colonies. Eggs can be collected using ovicups, which are small plastic cups lined with seed-germination paper and partially filled with leaf-infused H2O. Once collected, dry eggs will remain viable for months and can be safely transported long distances back to the laboratory as long as they are properly stored. This protocol provides step-by-step instructions for preparing for collecting, storing, and hatching Ae. aegypti eggs and has successfully yielded laboratory colonies from locations across both the native and invasive range of this species.

Mosquito Larvae and Pupae Transport from the Field.

Laboratory study of field-collected mosquitoes can allow researchers to better understand the ways variation within and among mosquito populations shapes burdens of mosquito-borne disease. The Anopheles gambiae complex comprises the most important vectors of malaria, but it can be challenging to keep in the laboratory. For some species of mosquitoes, especially An. gambiae, it is very difficult to bring viable eggs into the laboratory. Instead, it is preferable to collect larvae or pupae and then transport them as carefully as possible back to the laboratory. This simple protocol allows a researcher to start new laboratory colonies from larvae or pupae collected from natural breeding sites or proceed directly to their planned experiments. The use of natural breeding sites provides additional reassurance that the resulting colonies are representative of natural populations.

[Characteristics of the migrant women attended by the Reproductive Health Care Services of the Catalan Health Institute.] / Características de las mujeres migradas atendidas por los Servicios de Salud Reproductiva del Institut Català de la Salut.

OBJECTIVE: The feminization of migration, the need to provide health care to an increasingly diverse population, seeking optimal health data led to considering this research. The objective was to determine the characteristics (socio-demographic profile, obstetric and gynecological record, and monitoring) of migrated pregnant women with a pregnancy process completed in 2019 in Catalonia compared to native women, in public centers (ASSIR-ICS). METHODS: This descriptive study was based on computerized clinical records of women in the 28 centers dependent on the ICS. A descriptive analysis of the variables was carried out to compare the origin of the pregnant women. The Pearson Chi-Square test at 5% and the corrected standardized residual was used to compare the groups and an analysis of variance for the comparison of means also at 5%. RESULTS: 36.315 women were analyzed and the resulting mean age was 31.1 years. The BMI at the beginning of pregnancy was 25.4 on average. Smoking habit was 18.1% among Spanish 17.3% among European. Sexist violence was 4% in Latin American women, being statistically higher than the rest. The risk of preeclampsia was 23.4% in sub-Saharan women. Gestational diabetes was diagnosed mainly among Pakistanis (18.5%). The prevalence of Sexually Transmitted Infections (STIs) was detected in Latin Americans (8.6%), Spanish (5.8%) and Europeans (4.5%). Sub-Saharan women performed insufficient ultrasound control (58.2%) and had the lowest percentage of visits with 49.5%. Pregnancy monitoring was insufficient in 79.9% of all rural pregnant women. CONCLUSIONS: There are differences derived from the geographical origins of pregnant women that condition access to health services.

OBJETIVO: La feminización de la migración y la necesidad de dar asistencia sanitaria a una población cada vez más diversa, buscando unos datos óptimos de salud, llevó a plantearse esta investigación. El objetivo fue determinar las características (perfil socio-demográfico, antecedentes obstétricos-ginecológicos y el seguimiento) de gestantes migradas con un proceso de embarazo finalizado en 2019 en Cataluña frente a las autóctonas, en centros públicos (ASSIR-ICS). METODOS: Este estudio descriptivo se basó en los registros de historia clínica informatizada de mujeres en veintiocho centros dependientes del ICS. Se analizaron las variables según la procedencia de las gestantes y se utilizó la prueba de Ji Cuadrado de Pearson al 5% acompañada del residuo estandarizado corregido para compararlas, así como el análisis de la varianza para la comparación de medias también al 5%. RESULTADOS: Se analizaron 36.315 registros con edad media de 31,1 años. El IMC al inicio de gestación fue de 25,4. El consumo de tabaco fue del 18,1% entre españolas y del 17,3% en el resto de las europeas. El cribado de violencia machista llegó al 4% en latinoamericanas, siendo estadísticamente superior al resto. El riesgo de preeclampsia fue del 23,4% en subsaharianas. La diabetes gestacional fue diagnosticada principalmente entre paquistaníes (18,5%). La prevalencia de Infecciones de Transmisión Sexual (ITS) fue del 8,6% en latinoamericanas, del 5,8% en españolas y del 4,5% en europeas. Las subsaharianas (58,2%) realizaron un control insuficiente de ecografías y un menor porcentaje de visitas con un 49,5%. El seguimiento del embarazo fue insuficiente en el 79,9% del total de las gestantes rurales. CONCLUSIONES: Existen diferencias derivadas del origen geográfico de las gestantes que condicionan el acceso a los servicios sanitarios.

Características de las mujeres migradas atendidas por los Servicios de Salud Reproductiva del Institut Català de la Salut / Characteristics of the migrant women attended by the Reproductive Health Care Services of the Catalan Health Institute

Fundamentos: La feminización de la migración y la necesidad de dar asistencia sanitaria a una población cada vez más diversa, buscandounos datos óptimos de salud, llevó a plantearse esta investigación. El objetivo fue determinar las características (perfil socio-demográfico,antecedentes obstétricos-ginecológicos y el seguimiento) de gestantes migradas con un proceso de embarazo finalizado en 2019 en Cataluñafrente a las autóctonas, en centros públicos (ASSIR-ICS). Métodos: Este estudio descriptivo se basó en los registros de historia clínica informatizada de mujeres en veintiocho centros dependientesdel ICS. Se analizaron las variables según la procedencia de las gestantes y se utilizó la prueba de Ji Cuadrado de Pearson al 5% acompañadadel residuo estandarizado corregido para compararlas, así como el análisis de la varianza para la comparación de medias también al 5%. Resultados: Se analizaron 36.315 registros con edad media de 31,1 años. El IMC al inicio de gestación fue de 25,4. El consumo de tabacofue del 18,1% entre españolas y del 17,3% en el resto de las europeas. El cribado de violencia machista llegó al 4% en latinoamericanas, siendoestadísticamente superior al resto. El riesgo de preeclampsia fue del 23,4% en subsaharianas. La diabetes gestacional fue diagnosticada principalmente entre paquistaníes (18,5%). La prevalencia de Infecciones de Transmisión Sexual (ITS) fue del 8,6% en latinoamericanas, del 5,8% enespañolas y del 4,5% en europeas. Las subsaharianas (58,2%) realizaron un control insuficiente de ecografías y un menor porcentaje de visitascon un 49,5%. El seguimiento del embarazo fue insuficiente en el 79,9% del total de las gestantes rurales. Conclusiones: Existen diferencias derivadas del origen geográfico de las gestantes que condicionan el acceso a los servicios sanitarios.(AU)

Background: The feminization of migration, the need to provide health care to an increasingly diverse population, seeking optimal healthdata led to considering this research. The objective was to determine the characteristics (socio-demographic profile, obstetric and gynecological record, and monitoring) of migrated pregnant women with a pregnancy process completed in 2019 in Catalonia compared to native women,in public centers (ASSIR-ICS). Methods: This descriptive study was based on computerized clinical records of women in the 28 centers dependent on the ICS. A descriptiveanalysis of the variables was carried out to compare the origin of the pregnant women. The Pearson Chi-Square test at 5% and the correctedstandardized residual was used to compare the groups and an analysis of variance for the comparison of means also at 5%. Results: 36.315 women were analyzed and the resulting mean age was 31.1 years. The BMI at the beginning of pregnancy was 25.4 onaverage. Smoking habit was 18.1% among Spanish 17.3% among European. Sexist violence was 4% in Latin American women, being statisticallyhigher than the rest. The risk of preeclampsia was 23.4% in sub-Saharan women. Gestational diabetes was diagnosed mainly among Pakistanis(18.5%). The prevalence of Sexually Transmitted Infections (STIs) was detected in Latin Americans (8.6%), Spanish (5.8%) and Europeans (4.5%).Sub-Saharan women performed insufficient ultrasound control (58.2%) and had the lowest percentage of visits with 49.5%. Pregnancy monitoring was insufficient in 79.9% of all rural pregnant women. Conclusions: There are differences derived from the geographical origins of pregnant women that condition access to health services.(AU)

Extensive variation and strain-specificity in dengue virus susceptibility among African Aedes aegypti populations.

African populations of the mosquito Aedes aegypti are usually considered less susceptible to infection by human-pathogenic flaviviruses than globally invasive populations found outside Africa. Although this contrast has been well documented for Zika virus (ZIKV), it is unclear to what extent it is true for dengue virus (DENV), the most prevalent flavivirus of humans. Addressing this question is complicated by substantial genetic diversity among DENV strains, most notably in the form of four genetic types (DENV1 to DENV4), that can lead to genetically specific interactions with mosquito populations. Here, we carried out a continent-wide survey of DENV susceptibility using a panel of field-derived Ae. aegypti colonies from across the African range of the species and a colony from Guadeloupe, French West Indies as non-African reference. We found considerable variation in the ability of African Ae. aegypti populations to acquire and replicate a panel of six DENV strains spanning the four DENV types. Although African Ae. aegypti populations were generally less susceptible than the reference non-African population from Guadeloupe, in several instances some African populations were equally or more susceptible than the Guadeloupe population. Moreover, the relative level of susceptibility between African mosquito populations depended on the DENV strain, indicating genetically specific interactions. We conclude that unlike ZIKV susceptibility, there is no clear-cut dichotomy in DENV susceptibility between African and non-African Ae. aegypti. DENV susceptibility of African Ae. aegypti populations is highly heterogeneous and largely governed by the specific pairing of mosquito population and DENV strain.

High-resolution species assignment of Anopheles mosquitoes using k-mer distances on targeted sequences.

The ANOSPP amplicon panel is a genus-wide targeted sequencing panel to facilitate large-scale monitoring of Anopheles species diversity. Combining information from the 62 nuclear amplicons present in the ANOSPP panel allows for a more senstive and specific species assignment than single gene (e.g. COI) barcoding, which is desirable in the light of permeable species boundaries. Here, we present NNoVAE, a method using Nearest Neighbours (NN) and Variational Autoencoders (VAE), which we apply to k-mers resulting from the ANOSPP amplicon sequences in order to hierarchically assign species identity. The NN step assigns a sample to a species-group by comparing the k-mers arising from each haplotype's amplicon sequence to a reference database. The VAE step is required to distinguish between closely related species, and also has sufficient resolution to reveal population structure within species. In tests on independent samples with over 80% amplicon coverage, NNoVAE correctly classifies to species level 98% of samples within the An. gambiae complex and 89% of samples outside the complex. We apply NNoVAE to over two thousand new samples from Burkina Faso and Gabon, identifying unexpected species in Gabon. NNoVAE presents an approach that may be of value to other targeted sequencing panels, and is a method that will be used to survey Anopheles species diversity and Plasmodium transmission patterns through space and time on a large scale, with plans to analyse half a million mosquitoes in the next five years.

Diurnal biting of malaria mosquitoes in the Central African Republic indicates residual transmission may be "out of control".

Malaria control interventions target nocturnal feeding of the Anopheles vectors indoors to reduce parasite transmission. Mass deployment of insecticidal bed nets and indoor residual spraying with insecticides, however, may induce mosquitoes to blood-feed at places and at times when humans are not protected. These changes can set a ceiling to the efficacy of these control interventions, resulting in residual malaria transmission. Despite its relevance for disease transmission, the daily rhythmicity of Anopheles biting behavior is poorly documented, most investigations focusing on crepuscular hours and nighttime. By performing mosquito collections 48-h around the clock, both indoors and outdoors, and by modeling biting events using circular statistics, we evaluated the full daily rhythmicity of biting in urban Bangui, Central African Republic. While the bulk of biting by Anopheles gambiae, Anopheles coluzzii, Anopheles funestus, and Anopheles pharoensis occurred from sunset to sunrise outdoors, unexpectedly ∼20 to 30% of indoor biting occurred during daytime. As biting events did not fully conform to any family of circular distributions, we fitted mixtures of von Mises distributions and found that observations were consistent with three compartments, corresponding indoors to populations of early-night, late-night, and daytime-biting events. It is not known whether these populations of biting events correspond to spatiotemporal heterogeneities or also to distinct mosquito genotypes/phenotypes belonging consistently to each compartment. Prevalence of Plasmodium falciparum in nighttime- and daytime-biting mosquitoes was the same. As >50% of biting occurs in Bangui when people are unprotected, malaria control interventions outside the domiciliary environment should be envisaged.