Search Results (14)

Aedes aegypti and Anopheles darlingi represent health challenges due to synthetic insecticide resistance. Hence, the essential oil from Piper humillimum is an alternative for vector control. In this study, the essential oil (3.5 ± 0.4% yield) alongside germacrene D (61.51%) and δ-cadinene (17.46%) showed larvicidal activity (LC₅₀ of 34.75 to 46.04 µg/mL), accompanied by an increase of hydrogen peroxide (H₂O₂) production (36.67 ± 1.52 to 81.33 ± 1.52 µmol H₂O₂ min⁻¹ mg⁻¹ protein), causing lipid (43.3 ± 6.02 to 81.67 ± 3.05 nmol malondialdehyde mg⁻¹ protein) and protein damages (61.67 ± 6.80 to 83.00 ± 2.64 nmol carbonyls mg⁻¹ protein). Further triggering an increase in superoxide dismutase (83.31 ± 6.80 to 95.00 ± 3.60 U mg⁻¹ protein) and catalase (74.31 ± 7.02 to 82.09 ± 1.00 µmol H₂O₂ min⁻¹ mg⁻¹ protein) activities. In addition, mixed-function oxidases (61.17 ± 11.37 to 73.52 ± 6.42 nmol cyt c min⁻¹ mg⁻¹ protein), α- and β-esterase (38.41 ± 4.04 to 61.31 ± 9.29 µmol min⁻¹ mg⁻¹ protein) levels increased. Conversely, glutathione S-transferase (GST) (11.01 ± 2.00 to 9.67 ± 3.05 µmol min⁻¹ mg⁻¹ protein) and acetylcholinesterase (AChE) (14.33 ± 3.78 to 17.00 ± 1.00 μmol min⁻¹ mg⁻¹ protein) were inhibited, corroborated by molecular docking, with germacrene D and δ-cadinene showing binding energies of −7.9 and −7.9 kcal/mol, 1.63 and 1.94 Ki for AChE, while for GST were −6.4 and 6.6 kcal/mol, and 20.5 and 15.50 Ki, respectively. These results demonstrate that the essential oil from P. humillimum is a promising multi-target alternative for the control of the investigated vectors. Full article

Background/Objectives: Vector-borne diseases (VBDs) remain a major global public health challenge, particularly in tropical and subtropical regions. In eastern Colombia, the department of Meta reports a high incidence of arboviral infections such as dengue, as well as parasitic diseases including malaria and leishmaniasis. This study aimed to conduct baseline entomological surveillance and molecular screening of Diptera vectors to detect the circulation of arboviruses and parasitic pathogens in two municipalities of Meta, Fuente de Oro and Vista Hermosa. Methods: Adult mosquitoes and sand flies were collected in both municipalities and identified primarily at the genus level, with Anopheles specimens identified to species level. A total of 790 insects were collected, of which 780 were processed in 148 pools and 10 were analyzed individually. Molecular detection of pathogens was performed using PCR and RT-PCR to screen for dengue virus (DENV) serotypes, Zika virus (ZIKV), Chikungunya virus (CHIKV), Oropouche virus (OROV), Plasmodium spp., and Leishmania spp. Results: DENV was detected in 34.8% (55/158) of the processed pools, with DENV-1 identified as the most prevalent serotype. Culex was the most abundant genus overall, particularly in Fuente de Oro, while Aedes predominated in Vista Hermosa. MIR estimates indicated higher molecular detection likelihood in Aedes compared with Culex. Plasmodium vivax and P. falciparum were detected in pools of Anopheles darlingi and Anopheles rangeli, respectively. No molecular evidence of Leishmania DNA was detected in Lutzomyia specimens, and no positive detections were observed for ZIKV, CHIKV, or OROV. Conclusions: The molecular detection of DENV and Plasmodium spp. in field-collected vectors provides valuable baseline evidence of pathogen circulation in Meta, Colombia. While the findings do not imply vector competence, they highlight the importance of sustained entomological surveillance to inform integrated vector control strategies and guide future studies incorporating species-level identification and longitudinal sampling in endemic regions. Full article

In Brazil, Nyssorhynchus darlingi stands out as the primary malaria vector. Chromosome inversions have long been recognized as critical evolutionary mechanisms in diverse organisms. In this study, we used biallelic SNPs to show that it is possible to detect chromosome inversions reliably with low coverage sequence data. We estimated chromosome inversions in an Amazon Basin sample of Ny. darlingi and compared them with Anopheles gambiae and Anopheles albimanus genomes in synteny analysis. The An. gambiae dataset benchmarked the inversion detection pipeline with known inversions. Genotyping by sequencing was performed using the LCSeqTools workflow for the lcWGS dataset with an average sequencing depth of 2x. A synteny analysis was performed for Ny. darlingi inversions regions with An. gambiae and An. albimanus genomes. The sliding window analysis of PCA components revealed 10 high-confidence candidate regions for chromosome inversions in Ny. darlingi genome and two known inversions for An. gambiae with possible identification of breakpoints and adjacent regions at lower resolution. We demonstrate that lcWGS is a cost-effective and accurate method for detecting chromosome inversions. We reliably detected chromosome inversions in Ny. darlingi from the Brazilian Amazon that does not share similar inversion arrangements in An. gambiae or An. albimanus genomes. Full article

Malaria, caused by a protozoan parasite of the genus Plasmodium and transmitted by mosquitoes of the genus Anopheles, remains a significant vector-borne disease worldwide. In 2018, Paraguay became the first country in the Americas in 45 years to be certified malaria-free by the World Health Organization. Between 2016 and 2017, a period with no reported human malaria cases, the presence of Plasmodium spp. in Anopheles mosquitoes was investigated in the departments of Caaguazú and Alto Paraná. These studies found that the most prevalent Anopheles species in Paraguay, including Anopheles albitarsis (59.4%), Anopheles strodei (21.5%), and other Anopheles species in smaller proportions, were all negative to the parasite. The objective of this study was to re-evaluate these presence data and to define environmentally suitable areas for Anopheles spp. and their association with bioclimatic variables using DIVA-GIS/MaxEnt software for the entomological surveillance of malaria risk in Paraguay. Results showed that areas of bioclimatic suitability included the Humid Chaco, Cerrado, Paraná Atlantic Forest, and Southern Cone Mesopotamian savanna ecoregions. The most relevant climatic variables were the precipitation of the wettest month (contribution of 80.4%) and the precipitation of the driest month (contribution of 18.4%). Anopheles albitarsis, also reported as a vector of the Venezuelan equine encephalitis virus in neighbouring countries, was the most abundant mosquito species. Anopheles darlingi, the main vector of malaria in Paraguay, was not found. However, species richness indices (Chao/ACE) suggest that cryptic or sibling species may be present. Finally, the possible succession of Anopheles species and their geographical segregation are discussed in scenarios of entomological surveillance and epidemiological risk. Full article

Anopheles darlingi is a major malaria vector in South America. Understanding its population dynamics is critical for designing effective vector control strategies. While various Anopheles collection methods exist, they may sample distinct populations. Microsatellite genotyping across nine loci was performed to characterize An. darlingi populations, which were collected in French Guiana between 6:30 p.m. and 7:00 a.m. using human landing catch (HLC) or Mosquito Magnet^® (MM) traps. Traps were arranged in a 3 × 3 Latin square design to minimize possible effects of geographical position. Pairwise F_ST index and discriminant analyses of principal components (DAPC) were used to make comparisons. A total of 431 An. darlingi were analyzed. No significant genetic differentiation was observed between collection methods or time slots (F_ST values non-significant, p > 0.25), with DAPC revealing a single genetic cluster. Despite documented phenotypic variations, no significant population structure was detected among An. darlingi sampled in a rural village in French Guiana via collection methods or time slots. These findings confirm that mosquitoes collected with these various methods or time slots are suitable for the molecular studies of An. darlingi in French Guiana. In this context, Mosquito Magnet^® traps could also represent an alternative to the now controversial human landing catch. Full article

Background: Among major public health problems, malaria stands out as a tropical disease caused by the Plasmodium protozoan, with mosquitoes of the Anopheles genus serving as its vectors. This disease affects a significant portion of the population, with the highest incidence in the Legal Amazon, a region responsible for 99% of cases. Although vector control strategies, such as the use of chemical insecticides, are commonly employed, mosquito resistance, environmental impacts, and risks to human health are driving the search for natural alternatives, including the application of essential oils. Objectives: This study investigates the larvicidal activity of Trattinnickia burserifolia Mart. essential oil against Anopheles darlingi. Methods: The essential oil was obtained through hydrodistillation, and its chemical composition was identified using gas chromatography–mass spectrometry. The larvicidal assay followed WHO protocols, testing oil concentrations ranging from 20 to 100 µg mL⁻¹. Results: Efficacy was evaluated after 24, 48, and 72 h to determine LC₅₀, LC₉₀, and other parameters. Chemical composition analysis revealed the presence of 40 compounds, primarily terpenes such as tricyclene, β-pinene, limonene, and α-pinene, which possess bioactive properties that contribute to vector control. The larvicidal activity test showed that LC₅₀ decreased with longer exposure times, indica ting increased efficacy over time. After 72 h, the LC₅₀ was 14.51 µg mL⁻¹, classifying the essential oil as highly effective. Conclusions: Therefore, T. burserifolia Mart. essential oil represents a promising natural alternative for malaria vector control. Full article

Anopheles darlingi mosquitoes are the main malaria vectors in the Amazon region and play a significant role in the high transmission cycle of Plasmodium vivax, particularly in areas undergoing degradation of the Amazon. Establishing an An. darlingi colony under laboratory conditions allows for critical studies on this vector, including insecticide resistance, vector competence, and the development of new tools for controlling vivax malaria. However, the establishment of mass-rearing mosquito colonies has proven challenging, with success being heavily dependent on supporting their reproduction. A key factor in this process is finding the most efficient blood source for feeding. Here, we evaluated the reproductive potential of An. darlingi using different blood feeding methods and sources. First, we assessed the effect of anesthesia on reproductive potential by comparing anesthetized mosquitoes with those that were physically restrained. Next, we assessed the best blood source using both direct and indirect blood feeding methods, the latter involving an artificial feeding system. The blood sources tested included from rabbits, chickens, mice, bovines, and humans. In the anesthesia tests, no significant differences in the evaluated biological parameters were observed between anesthetized or non-anesthetized groups. Similarly, no significant differences were detected in the biological parameters assessed for each blood source, regardless of whether the feeding was direct or indirect. Because all blood sources proved effective, the practicality of obtaining and maintaining blood becomes a crucial factor. In this regard, bovine blood emerged as an effective and practical alternative for maintaining an An. darlingi colony under laboratory conditions. Full article

Malaria disease affects millions of people annually, making the Amazon Basin a major hotspot in the Americas. While traditional control strategies rely on physical and chemical methods, the Anopheles microbiome offers a promising avenue for biological control, as certain bacteria can inhibit parasite development and alter vector immune and reproductive systems, disrupting the transmission cycle. For this reason, this study aimed to explore the bacterial communities in An. darlingi and An. triannulatus s.l., including breeding sites, immature stages, and adults from San Pedro de los Lagos (Leticia, Amazonas) through next-generation sequencing of the 16S rRNA gene. The results revealed a higher bacterial genus richness in the L1–L2 larvae of An. triannulatus s.l. Aeromonas and Enterobacter were prevalent in most samples, with abundances of 52.51% in L3–L4 larvae and 48.88% in pupae of An. triannulatus s.l., respectively. In breeding site water, Verrucomicrobiota bacteria were the most dominant (52.39%). We also identified Delftia (15.46%) in An. triannulatus s.l. pupae and Asaia (98.22%) in An. triannulatus, linked to Plasmodium inhibition, and Elizabethkingia, in low abundances, along with Klebsiella and Serratia, known for paratransgenesis potential. Considering the high bacterial diversity observed across the different mosquito life stages, identifying bacterial composition is the first step towards developing new strategies for malaria control. However, the specific roles of these bacteria in anophelines and the malaria transmission cycle remain to be elucidated. Full article

Aedes aegypti and Anopheles darlingi are the primary vectors of dengue and malaria in Brazil. Natural products are currently regarded as promising alternatives for their control, offering environmentally friendly solutions for larval management due to their low toxicity to non-target organisms. Thus, Piplartine, isolated for the first time from Piper purusanum, exhibited larvicidal activity against Ae. aegypti and An. darlingi (LC₅₀ of 14.56 and 26.44 μg/mL), occasioned by the overproduction of reactive oxygen and nitrogen species (66.67 ± 7% and 86.33 ± 6%). Furthermore, piplartine enhanced the activity of key detoxifying enzymes, including catalase (87.00 ± 9 and 94.67 ± 9 μmol of H₂O₂ consumed per minute per mg of protein), glutathione S-transferase (76.00 ± 1 and 134.00 ± 1 μmol/min/mg), mixed-function oxidase (26.67 ± 5 and 55.00 ± 1 nmol cti mg⁻¹ protein), α-esterase, and β-esterase (27.67 ± 7 to 46.33 ± 1 nmol cti mg⁻¹ protein). In contrast, piplartine inhibited acetylcholinesterase activity (43.33 ± 7 and 48.00 ± 2 μmol/min/mg) compared to the negative control DMSO (87.33 ± 1 and 146.30 ± 3 μmol/min/mg). It is important to highlight that piplartine showed no lethal effects on non-target aquatic insects, with 100% survival observed at a concentration of 264.4 μg/mL. In contrast, α-cypermethrin demonstrated acute and rapid toxicity to non-target organisms, with only 9.1% survival. These findings highlight piplartine as a promising larvicide with selective toxicity and low environmental impact, suitable for integrated larval management strategies. Full article

Anopheles species composition, abundance, and Plasmodium natural infection are important aspects to assess malaria transmission risk. In this study, these aspects were evaluated in a large number of localities in the most important malaria-endemic regions of Colombia. Mosquitoes were collected from 2012 to 2015 in 55 localities of northwestern and western Colombia. Anopheles species composition, abundance, and Plasmodium infection were estimated. A total of 13,218 Anopheles specimens were evaluated. The highest species richness was detected in the northwest, where the main vectors, An. albimanus (27.8%) and An. nuneztovari (26.7%), were the most abundant species. In the west, An. nuneztovari predominated (51.6%), followed by An. darlingi (29.2%). Six species were infected with Plasmodium, An. darlingi, An. nuneztovari, An. albimanus, An. calderoni, An. triannulatus, and An. braziliensis. Results showed that in these localities the main Colombian vectors are widely spread, which suggests a high malaria risk. Notably, this study is the first to report An. braziliensis from Colombia as being naturally infected with Plasmodium. Infection results for species that are suspected local vectors indicate the importance of conducting further studies to assess their epidemiological importance. This information provides the basis for the application of directed vector control strategies that are species-specific. Full article

The maintenance of a highly productive colony of anopheline mosquitoes requires standardized methods in order to obtain a sufficient number of homogeneous individuals for malaria research. In this context, nutritional status may affect survival, fecundity, and the capacity to support pathogen development. Here we assess the effects of carbohydrate sources on fecundity, survival, and susceptibility to Plasmodium vivax infection in colonies of Anopheles darlingi and Anopheles deaneorum mosquitoes. Newly emerged females from each species were fed either 10% sugar or 15% honey solutions until the end of each experiment. The type of carbohydrate meal did not impact any entomological parameters for An. deaneorum, except for survival. For both species, honey meal significantly increased median survival post-emergence by three to four days, probably due to its nutritional value. For An. darlingi fed with honey, a higher mean frequency in stage 5 was observed at 48 h post-blood-meal, which could indicate a delay in the digestion process. However, no effects on fecundity parameters were observed. Regarding susceptibility, An. darlingi fed with sugar exhibited a low intensity of sporozoites, although any negative effects of sucrose on sporozoites invasions in the salivary glands are unknown. Based on the increase in mosquito survival, a carbohydrate source composed of 15% honey solution could be better for maintaining An. darlingi and An. deaneorum in the lab-rearing context. Full article

Anopheles darlingi is a major malaria vector in the Amazon region and, like other vectors, harbors a community of microorganisms with which it shares a network of interactions. Here, we describe the diversity and bacterial composition from the midguts and salivary glands of lab-reared and field-captured An. darlingi using metagenome sequencing of the 16S rRNA gene. The libraries were built using the amplification of the region V3–V4 16S rRNA gene. The bacterial community from the salivary glands was more diverse and richer than the community from the midguts. However, the salivary glands and midguts only showed dissimilarities in beta diversity between lab-reared mosquitoes. Despite that, intra-variability was observed in the samples. Acinetobacter and Pseudomonas were dominant in the tissues of lab-reared mosquitoes. Sequences of Wolbachia and Asaia were both found in the tissue of lab-reared mosquitoes; however, only Asaia was found in field-captured An. darlingi, but in low abundance. This is the first report on the characterization of microbiota composition from the salivary glands of An. darlingi from lab-reared and field-captured individuals. This study can provide invaluable insights for future investigations regarding mosquito development and interaction between mosquito microbiota and Plasmodium sp. Full article

The genome assembly of Anopheles darlingi consists of 2221 scaffolds (N50 = 115,072 bp) and has a size spanning 136.94 Mbp. This assembly represents one of the smallest genomes among Anopheles species. Anopheles darlingi genomic DNA fragments of ~37 Kb were cloned, end-sequenced, and used as probes for fluorescence in situ hybridization (FISH) with salivary gland polytene chromosomes. In total, we mapped nine DNA probes to scaffolds and autosomal arms. Comparative analysis of the An. darlingi scaffolds with homologous sequences of the Anopheles albimanus and Anopheles gambiae genomes identified chromosomal rearrangements among these species. Our results confirmed that physical mapping is a useful tool for anchoring genome assemblies to mosquito chromosomes. Full article

In Brazil, malaria transmission is mostly confined to the Amazon, where substantial progress has been made towards disease control in the past decade. Vector control has been historically considered a fundamental part of the main malaria control programs implemented in Brazil. However, the conventional vector-control tools have been insufficient to control or eliminate local vector populations due to the complexity of the Amazonian rainforest environment and ecological features of malaria vector species in the Amazon, especially Anopheles darlingi. Malaria elimination in Brazil and worldwide eradication will require a combination of conventional and new approaches that takes into account the regional specificities of vector populations and malaria transmission dynamics. Here we present an overview on both conventional and novel promising vector-focused tools to curb malaria transmission in the Brazilian Amazon. If well designed and employed, vector-based approaches may improve the implementation of malaria-control programs, particularly in remote or difficult-to-access areas and in regions where existing interventions have been unable to eliminate disease transmission. However, much effort still has to be put into research expanding the knowledge of neotropical malaria vectors to set the steppingstones for the optimization of conventional and development of innovative vector-control tools. Full article