Multilocus genetic analysis of Trypanosoma cruzi supports non-domestic intrusion into domestic transmission in an endemic region of Colombia.

Trypanosoma cruzi, the causative agent of Chagas disease, is primarily transmitted to humans by hematophagous bugs of the Triatominae subfamily. In the Colombian Caribbean region, particularly on Margarita Island, T. cruzi transmission is highly endemic and associated with vectors such as Triatoma maculata and Rhodnius pallescens. Additionally, T. cruzi-infected Didelphis marsupialis are commonly found in close proximity to human dwellings. Given the complex transmission dynamics involving various domestic and non-domestic hosts, this study aimed to analyze 145 T. cruzi clones from twelve strains isolated from T. maculata, R. pallescens, and D. marsupialis using spliced leader intergenic region (SL-IR) sequences and nine polymorphic microsatellite loci. The results indicate the presence of a single polymorphic T. cruzi population, suggesting sustained local transmission dynamics between triatomines adapted to A. butyracea forests and peridomestic areas inhabited by synanthropic mammal reservoir such as D. marsupialis. Notably, this population appears to lack substructure, highlighting the importance of adopting an alternative eco-health approach to complement traditional chemical vector control methods for more effective and sustainable interruption of transmission.

PUF3 RNA binding protein of Trypanosoma cruzi regulates mitochondrial morphology and function.

The RNA-binding PUF proteins are post-transcriptional regulators found throughout the eukaryotic domain. In Trypanosoma cruzi, ten Puf genes termed Puf1 to Puf10 have been identified. Considering that the control of gene expression in this parasite is mainly at the post-transcriptional level, we characterized the PUF3 protein by knocking out and overexpressing the gene in T. cruzi epimastigotes and studied different genetic and biological features. The RNA-seq analyses in both genotypes showed significant changes in the number of regulated transcripts compared with wild-type parasites. Thus, the number of differentially expressed genes in the knockout (ΔTcPuf3) and the overexpressor (pTEXTcPuf3) were 238 and 187, respectively. In the knockout, a more significant proportion of genes was negatively regulated (166 out of 238). In contrast, in the overexpressor, positively regulated genes were predominant (149 out of 170). Additionally, when we predicted the subcellular location of the differentially expressed genes, the results revealed an important representation of nuclear genes encoding mitochondrial proteins. Therefore, we determined whether overexpression or knockout of TcPuf3 could lead to changes in both mitochondrial structure and cellular respiration. When mitochondria from ΔTcPuf3 and pTEXTcPuf3 parasites were analyzed by transmission electron microscopy (TEM), it was observed that the overexpressor had an abnormal mitochondrial morphology, evidenced by swelling. The results associated with cellular respiration showed that both the ΔTcPuf3 and pTEXTcPuf3 had a lower efficiency in routine respiration and the electron transport system capacity. Likewise, the mitochondria from overexpressing parasites showed a slight hyperpolarization. Additionally, several biological features, depending on the function of the mitochondria, were altered, such as growth, cell division, metacyclogenesis, ROS production, and response to benznidazole. In conclusion, our results suggest that although PUF3 is not an essential protein in T. cruzi, it influences mitochondrial transcripts, affecting mitochondrial morphology and function.

Tackling the cytotoxicity and genotoxicity of cellulose nanofibers from the banana rachis: A new food packaging alternative.

Cellulose nanofibrils from the banana rachis are a good alternative as packaging materials, food packaging, stabilizing agents, and functional food ingredients. To address the potential effects of ingested banana rachis cellulose nanofibrils (BR-CNFs), their toxicity in vitro and in vivo was evaluated using Caco-2 intestinal cells and mice, respectively. The results showed that BR-CNFs did not cause cytotoxic effects at the concentrations evaluated on Caco-2 cells. In addition to cytotoxicity tests, genotoxicity assays using comet assay indicated that Caco-2 cells showed no DNA damage at the concentrations of CNFs tested. Finally, acute in vivo cytotoxicity assays indicated that mice showed no sign of pathogenesis or lesions in the liver, kidney, or small intestine when treated with a single dose of BR-CNFs. Moreover, when the mice were treated daily for a month with BR-CNFs no hyperplasia or hypertrophy was observed in any of the organs evaluated. Additionally, biochemical parameters such as blood chemistry, creatinine, liver enzymes, and renal function showed that the BR-CNFs do not cause organ damage. Overall, this study shows that BR-CNFs are neither cytotoxic nor genotoxic. In conclusion, these studies are essential to guarantee the safety of this high value-added product in the food industry.

Epidemiological features of Leishmania infantum in dogs (Canis lupus familiaris) suggest a latent risk of visceral leishmaniasis in the metropolitan area of Bucaramanga, Santander, Eastern Colombia.

Visceral leishmaniasis (VL) is a disease caused by species of the Leishmania donovani complex that is mainly transmitted through the urban cycle involving dogs as the primary reservoir. In Colombia, the incidence of VL is increasing, along with the spread of potential vectors. This study aims to investigate the eco-epidemiological factors associated with Leishmania spp. infection in dogs from the Metropolitan Area of Bucaramanga (MAB), Santander, eastern Colombia, which is a region at risk for VL. We conducted molecular and serological surveillance of Leishmania spp. in 207 dogs from MAB to determine the epidemiological factors associated with infection. Subsequently, we carried out a molecular and serological analysis of phlebotomine and humans, respectively, in areas with a higher prevalence of infection, aiming to describe the main features associated with the transmission cycle. Out of the 207 dogs tested, 37 (17.8%, 95% CI = 12.6-23.1%) were positive for the presence of Leishmania antibodies by the IFAT test, and only 9 (4.3%, 95% CI = 1.55-7.15%) were positive for L. infantum by PCR. Multivariate analyses indicated that canine shelters and dogs with clinical signs commonly associated with canine VL had a higher prevalence of infection (P < 0.05). In the entomological survey, 69 blood-fed female phlebotomine of the genus Lutzomyia were captured in canine shelters, among them, 55% were identified as Lutzomyia camposi, 29% as Lu. ovallesi, 7% as Lu. dubitans, 6% as Lu. torvida, and 3% as Lu. cayennensis. The identified meal sources of the phlebotomine included human, pig, avian, cattle, and porcupine (Coendou quichua) blood. However, no phlebotomine positive for Leishmania spp. were detected by molecular analyses. Finally, 14 humans who had frequent contact with L. infantum-positive dogs were analyzed through rK39 test, but none tested was positive for IgG/IgM antibodies. The molecular and serological analyses indicate the circulation of L. infantum in dogs from MAB, with canine shelters having the highest prevalence of infection. The entomological survey of canine shelters showed a significant diversity of phlebotomine without potential vectors of L. infantum, suggesting the presence of infection in dogs from these areas could take place in other locations or through other transmission routes. The circulation of L. infantum in multiple dogs from MAB suggests a latent risk of zoonotic transmission of VL in these cities.

Bioprinted Multicomponent Hydrogel Co-culture Tumor-Immune Model for Assessing and Simulating Tumor-Infiltrated Lymphocyte Migration and Functional Activation.

The immune response against a tumor is characterized by the interplay among components of the immune system and neoplastic cells. Here, we bioprinted a model with two distinct regions containing gastric cancer patient-derived organoids (PDOs) and tumor-infiltrated lymphocytes (TILs). The initial cellular distribution allows for the longitudinal study of TIL migratory patterns concurrently with multiplexed cytokine analysis. The chemical properties of the bioink were designed to present physical barriers that immune T-cells must breech during infiltration and migration toward a tumor with the use of an alginate, gelatin, and basal membrane mix. TIL activity, degranulation, and regulation of proteolytic activity reveal insights into the time-dependent biochemical dynamics. Regulation of the sFas and sFas-ligand present on PDOs and TILs, respectively, and the perforin and granzyme longitudinal secretion confirms TIL activation when encountering PDO formations. TIL migratory profiles were used to create a deterministic reaction-advection diffusion model. The simulation provides insights that decouple passive from active cell migration mechanisms. The mechanisms used by TILs and other adoptive cell therapeutics as they infiltrate the tumor barrier are poorly understood. This study presents a pre-screening strategy for immune cells where motility and activation across ECM environments are crucial indicators of cellular fitness.

Knee skin temperature response of patients with bilateral patellofemoral syndrome before and after heat and cold stress.

Patellofemoral Pain Syndrome is characterized by the presence of pain in the front area of the knee, which occurs when performing common activities such as climbing stairs, and bending the knees, among others. The objective of this research was to evaluate the detection capability of infrared thermography in patients with Patellofemoral Pain Syndrome, in the baseline state, as well as after the application of thermal stress. The investigation was conducted in 48 patients, who were subdivided into four groups (n = 12). Two subgroups were healthy patients and two with Patellofemoral Pain Syndrome. For the diagnosis of the syndrome, a manual evaluation was performed using the Zohlen test and Q angle measurement. Subsequently, cold stress was applied for 10 min to a healthy subgroup and an experimental subgroup. The remaining two subgroups were subjected to heat stress for 15 min. Thermographic images of the lower extremities were acquired at seven time points, at baseline, immediately after application of thermal stress and then every 3 min until 15 min were completed. It was observed that patients presented Patellofemoral Pain Syndrome bilaterally. After statistical analysis, it was found that there were no significant differences in baseline temperature between the groups. However, for heat stress, a higher temperature was observed in the group with Patellofemoral Pain Syndrome (p < 0.05) in the recovery period, and in the case of cold stress, only a lower temperature in the left knee immediately after the application. In conclusion, it is not possible to detect patellofemoral syndrome bilaterally in the baseline state by thermography and neither is it evident in cold stress. However, after heat stress, thermal recovery is lower for the PFPS group, so it would be susceptible to detection.

Evolution of a Mosquito's Hatching Behavior to Match Its Human-Provided Habitat.

AbstractA subspecies of the yellow fever mosquito, Aedes aegypti, has recently evolved to specialize in biting and living alongside humans. It prefers human odor over the odor of nonhuman animals and breeds in human-provided artificial containers rather than the forest tree holes of its ancestors. Here, we report one way this human specialist has adapted to the distinct ecology of human environments. While eggs of the ancestral subspecies rarely hatch in pure water, those of the derived human specialist do so readily. We trace this novel behavior to a shift in how eggs respond to dissolved oxygen, low levels of which may signal food abundance. Moreover, we show that while tree holes are consistently low in dissolved oxygen, artificial containers often have much higher levels. There is thus a concordance between the hatching behavior of each subspecies and the aquatic habitat it uses in the wild. We find this behavioral variation is heritable, with both maternal and zygotic effects. The zygotic effect depends on dissolved oxygen concentration (i.e., a genotype-environment interaction, or G×E), pointing to potential changes in oxygen-sensitive circuits. Together, our results suggest that a shift in hatching response contributed to the pernicious success of this human-specialist mosquito and illustrate how animals may rapidly adapt to human-driven changes in the environment.

Constructing 3D In Vitro Models of Heterocellular Solid Tumors and Stromal Tissues Using Extrusion-Based Bioprinting.

Malignant tumor tissues exhibit inter- and intratumoral heterogeneities, aberrant development, dynamic stromal composition, diverse tissue phenotypes, and cell populations growing within localized mechanical stresses in hypoxic conditions. Experimental tumor models employing engineered systems that isolate and study these complex variables using in vitro techniques are under development as complementary methods to preclinical in vivo models. Here, advances in extrusion bioprinting as an enabling technology to recreate the three-dimensional tumor milieu and its complex heterogeneous characteristics are reviewed. Extrusion bioprinting allows for the deposition of multiple materials, or selected cell types and concentrations, into models based upon physiological features of the tumor. This affords the creation of complex samples with representative extracellular or stromal compositions that replicate the biology of patient tissue. Biomaterial engineering of printable materials that replicate specific features of the tumor microenvironment offer experimental reproducibility, throughput, and physiological relevance compared to animal models. In this review, we describe the potential of extrusion-based bioprinting to recreate the tumor microenvironment within in vitro models.

Molecular characterization of Ehrlichia canis and Babesia vogeli reveals multiple genogroups associated with clinical traits in dogs from urban areas of Colombia.

Ehrlichia canis and Babesia vogeli are vector-borne pathogens that infect blood cells and produce the diseases Canine Monocytic Ehrlichiosis (CME) and Babesiosis in dogs. Considering the lack of studies on these pathogens in Colombia, this study aims to determine the molecular prevalence and genetic characterization of E. canis and Babesia spp., in dogs from the Metropolitan Area of Bucaramanga (MAB), Santander, a region with one of the greatest pet densities in Colombia. One hundred eighty-five dogs were surveyed and analyzed through molecular, clinical, and hematological approaches. The molecular detection of E. canis and Babesia spp., was performed by conventional PCR targeting the dsb and 18S rRNA genes, respectively. To identify genogroups, E. canis positive samples underwent a hemi-nested PCR of the trp36 gene, and the PCR products were subsequently sequenced. Molecular analyses showed a prevalence of 13% (24/185; CI 95%, 8.1 - 18.0%) and 1.09% (2/185; CI 95,% -0.43 - 2.6%) for E. canis and B. vogeli respectively, as well as the presence of the genogroups US (USA), BR (Brazil), and CR (Costa Rica), in 62.5, 16.6, and 16.6% of E. canis positive samples, respectively. Values of hematocrit, hemoglobin, platelets, erythrocytes, white blood cell (WBC) count, lymphocytes, and eosinophils showed significant differences between animals infected with the different genogroups of E. canis (p< 0.05). In contrast, hematocrit values, hemoglobin, platelets, red blood cells, and creatine kinase MB isoenzyme (CK-MB) were lower in B. vogeli positive animals. Statistical analysis indicated that E. canis infection was associated with specific socioeconomic sectors as well as with some household features (p< 0.05). In conclusion, our results present evidence of the circulation of multiple genogroups of E. canis in the MAB, which is associated with different geographical origins and clinical traits. Epidemiological analyses suggest a need to increase molecular surveillance and prevention campaigns especially in lower socioeconomic sectors.

Decellularized ECM hydrogels: prior use considerations, applications, and opportunities in tissue engineering and biofabrication.

Tissue development, wound healing, pathogenesis, regeneration, and homeostasis rely upon coordinated and dynamic spatial and temporal remodeling of extracellular matrix (ECM) molecules. ECM reorganization and normal physiological tissue function, require the establishment and maintenance of biological, chemical, and mechanical feedback mechanisms directed by cell-matrix interactions. To replicate the physical and biological environment provided by the ECM in vivo, methods have been developed to decellularize and solubilize tissues which yield organ and tissue-specific bioactive hydrogels. While these biomaterials retain several important traits of the native ECM, the decellularizing process, and subsequent sterilization, and solubilization result in fragmented, cleaved, or partially denatured macromolecules. The final product has decreased viscosity, moduli, and yield strength, when compared to the source tissue, limiting the compatibility of isolated decellularized ECM (dECM) hydrogels with fabrication methods such as extrusion bioprinting. This review describes the physical and bioactive characteristics of dECM hydrogels and their role as biomaterials for biofabrication. In this work, critical variables when selecting the appropriate tissue source and extraction methods are identified. Common manual and automated fabrication techniques compatible with dECM hydrogels are described and compared. Fabrication and post-manufacturing challenges presented by the dECM hydrogels decreased mechanical and structural stability are discussed as well as circumvention strategies. We further highlight and provide examples of the use of dECM hydrogels in tissue engineering and their role in fabricating complex in vitro 3D microenvironments.

Use of Fourier Series in X-ray Diffraction (XRD) Analysis and Fourier-Transform Infrared Spectroscopy (FTIR) for Estimation of Crystallinity in Cellulose from Different Sources.

Cellulose crystallinity can be described according to the crystal size and the crystallinity index (CI). In this research, using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods, we studied the crystallinity of three different types of cellulose: banana rachis (BR), commercial cellulose (CS), and bacterial cellulose (BC). For each type of cellulose, we analyzed three different crystallization grades. These variations were obtained using three milling conditions: 6.5 h, 10 min, and unmilled (films). We developed a code in MATLAB software to perform deconvolution of the XRD data to estimate CI and full width at half-maximum (FWHM). For deconvolution, crystalline peaks were represented with Voigt functions, and a Fourier series fitted to the amorphous profile was used as the amorphous contribution, which allowed the contribution of the amorphous profile to be more effectively modeled. Comparisons based on the FTIR spectra and XRD results showed there were no compositional differences between the amorphous samples. However, changes associated with crystallinity were observed when the milling time was 10 min. The obtained CI (%) values show agreement with values reported in the literature and confirm the effectiveness of the method used in this work in predicting the crystallization aspects of cellulose samples.

Enzootic Trypanosoma cruzi infection by Rhodnius prolixus shows transmission to humans and dogs in Vichada, Colombia.

Background: Rhodnius prolixus is considered the most relevant Trypanosoma cruzi vector in Colombia and Venezuela due it is responsible for domestic transmission in both countries. However, a wild population of this species is distributed in the eastern plains of the Orinoco region and Amazonia jungle, where its epidemiological importance has not been sufficiently elucidated. This study aimed to assess epidemiological parameters of T. cruzi transmission in the Department of Vichada, Colombia. Methods: We determined the characteristics of T. cruzi transmission using entomological studies in domestic and sylvatic ecotopes. We analyzed the T. cruzi infection in triatomine insects, identified blood meal sources, and conducted a serological determination of T. cruzi infection in scholar-aged children, domestic dogs, and wild hosts. Results: Fifty-four triatomine bugs, 40 T. maculata and 14 R. prolixus were collected in peridomestic and sylvatic ecotopes. Infected R. prolixus was observed in La Primavera, Santa Rosalia, and Cumaribo municipalities. All the T. maculata bugs were not infected. Serological analysis indicated that two of 3,425 children were T. cruzi positive. The seroprevalence in domestic dogs was 10,5% (49/465). Moreover, 22 synanthropic mammals were sampled, being Didelphis marsupialis the most common. TcI genotype was detected in seropositive dogs, R. prolixus, and D. marsupialis. Conclusion: The present work describes extra domestic R. prolixus and D. marsupialis in a sylvatic T. cruzi transmission cycle with transmission to humans and domestic dogs in Colombia's Vichada Department.

Laboratory Evaluation and Field Feasibility of Micro-Encapsulated Insecticide Effect on Rhodnius prolixus and Triatoma dimidiata Mortality in Rural Households in Boyacá, Colombia.

Chagas disease is a neglected vector-borne zoonosis caused by the parasite Trypanosoma cruzi that is primarily transmitted by insects of the subfamily Triatominae. Although control efforts targeting domestic infestations of Rhodnius prolixus have been largely successful, with several regions in Boyacá department certified free of T. cruzi transmission by intradomicile R. prolixus, novel native species are emerging, increasing the risk of disease. Triatoma dimidiata is the second most important species in Colombia, and conventional control methods seem to be less effective. In this study we evaluated the efficacy and usefulness of micro-encapsulated insecticide paints in laboratory conditions and its applicability in rural communities to avoid triatomine domiciliation. Laboratory conditions measured mortality at 6 months and 12 months, with an average mortality between 93-100% for T. dimidiata and 100% for R. prolixus. Evaluation of triatomine infestation in rural households was measured after one year, with an overall perception of effectiveness in reducing household domiciliation. Although triatomines were still spotted inside and around the homes, our findings demonstrate the ability of micro-encapsulated insecticide to prevent colonization inside the households when comparing infestation rates from previous years. Current control measures suggest insecticide spraying every six months, which implies great economic cost and logistical effort. Complementary triatomine control measures with insecticide spraying and micro-encapsulated insecticide paint would make public health efforts more efficient and reduce the frequency of treatment.

Association of Midgut Bacteria and Their Metabolic Pathways with Zika Infection and Insecticide Resistance in Colombian Aedes aegypti Populations.

INTRODUCTION: Aedes aegypti is the vector of several arboviruses such as dengue, Zika, and chikungunya. In 2015-16, Zika virus (ZIKV) had an outbreak in South America associated with prenatal microcephaly and Guillain-Barré syndrome. This mosquito's viral transmission is influenced by microbiota abundance and diversity and its interactions with the vector. The conditions of cocirculation of these three arboviruses, failure in vector control due to insecticide resistance, limitations in dengue management during the COVID-19 pandemic, and lack of effective treatment or vaccines make it necessary to identify changes in mosquito midgut bacterial composition and predict its functions through the infection. Its study is fundamental because it generates knowledge for surveillance of transmission and the risk of outbreaks of these diseases at the local level. METHODS: Midgut bacterial compositions of females of Colombian Ae. aegypti populations were analyzed using DADA2 Pipeline, and their functions were predicted with PICRUSt2 analysis. These analyses were done under the condition of natural ZIKV infection and resistance to lambda-cyhalothrin, alone and in combination. One-step RT-PCR determined the percentage of ZIKV-infected females. We also measured the susceptibility to the pyrethroid lambda-cyhalothrin and evaluated the presence of the V1016I mutation in the sodium channel gene. RESULTS: We found high ZIKV infection rates in Ae. aegypti females from Colombian rural municipalities with deficient water supply, such as Honda with 63.6%. In the face of natural infection with an arbovirus such as Zika, the diversity between an infective and non-infective form was significantly different. Bacteria associated with a state of infection with ZIKV and lambda-cyhalothrin resistance were detected, such as the genus Bacteroides, which was related to functions of pathogenicity, antimicrobial resistance, and bioremediation of insecticides. We hypothesize that it is a vehicle for virus entry, as it is in human intestinal infections. On the other hand, Bello, the only mosquito population classified as susceptible to lambda-cyhalothrin, was associated with bacteria related to mucin degradation functions in the intestine, belonging to the Lachnospiraceae family, with the genus Dorea being increased in ZIKV-infected females. The Serratia genus presented significantly decreased functions related to phenazine production, potentially associated with infection control, and control mechanism functions for host defense and quorum sensing. Additionally, Pseudomonas was the genus principally associated with functions of the degradation of insecticides related to tryptophan metabolism, ABC transporters with a two-component system, efflux pumps, and alginate synthesis. CONCLUSIONS: Microbiota composition may be modulated by ZIKV infection and insecticide resistance in Ae. aegypti Colombian populations. The condition of resistance to lambda-cyhalothrin could be inducing a phenome of dysbiosis in field Ae. aegypti affecting the transmission of arboviruses.

Rapid Evaporative Ionization Mass Spectrometry (REIMS): a Potential and Rapid Tool for the Identification of Insecticide Resistance in Mosquito Larvae.

Insecticide resistance is a significant challenge facing the successful control of mosquito vectors globally. Bioassays are currently the only method for phenotyping resistance. They require large numbers of mosquitoes for testing, the availability of a susceptible comparator strain, and often insectary facilities. This study aimed to trial the novel use of rapid evaporative ionization mass spectrometry (REIMS) for the identification of insecticide resistance in mosquitoes. No sample preparation is required for REIMS and analysis can be rapidly conducted within hours. Temephos resistant Aedes aegypti (Linnaeus) larvae from Cúcuta, Colombia and temephos susceptible larvae from two origins (Bello, Colombia, and the lab reference strain New Orleans) were analyzed using REIMS. We tested the ability of REIMS to differentiate three relevant variants: population source, lab versus field origin, and response to insecticide. The classification of these data was undertaken using linear discriminant analysis (LDA) and random forest. Classification models built using REIMS data were able to differentiate between Ae. aegypti larvae from different populations with 82% (±0.01) accuracy, between mosquitoes of field and lab origin with 89% (±0.01) accuracy and between susceptible and resistant larvae with 85% (±0.01) accuracy. LDA classifiers had higher efficiency than random forest with this data set. The high accuracy observed here identifies REIMS as a potential new tool for rapid identification of resistance in mosquitoes. We argue that REIMS and similar modern phenotyping alternatives should complement existing insecticide resistance management tools.

Local-scale virome depiction in Medellín, Colombia, supports significant differences between Aedes aegypti and Aedes albopictus.

Aedes spp. comprise the primary group of mosquitoes that transmit arboviruses such as dengue, Zika, and chikungunya viruses to humans, and thus these insects pose a significant burden on public health worldwide. Advancements in next-generation sequencing and metagenomics have expanded our knowledge on the richness of RNA viruses harbored by arthropods such as Ae. aegypti and Ae. albopictus. Increasing evidence suggests that vector competence can be modified by the microbiome (comprising both bacteriome and virome) of mosquitoes present in endemic zones. Using an RNA-seq-based metataxonomic approach, this study determined the virome structure, Wolbachia presence and mitochondrial diversity of field-caught Ae. aegypti and Ae. albopictus mosquitoes in Medellín, Colombia, a municipality with a high incidence of mosquito-transmitted arboviruses. The two species are sympatric, but their core viromes differed considerably in richness, diversity, and abundance; although the community of viral species identified was large and complex, the viromes were dominated by few virus species. BLAST searches of assembled contigs suggested that at least 17 virus species (16 of which are insect-specific viruses [ISVs]) infect the Ae. aegypti population. Dengue virus 3 was detected in one sample and it was the only pathogenic virus detected. In Ae. albopictus, up to 11 ISVs and one plant virus were detected. Therefore, the virome composition appears to be species-specific. The bacterial endosymbiont Wolbachia was identified in all Ae. albopictus samples and in some Ae. aegypti samples collected after 2017. The presence of Wolbachia sp. in Ae. aegypti was not related to significant changes in the richness, diversity, or abundance of this mosquito's virome, although it was related to an increase in the abundance of Aedes aegypti To virus 2 (Metaviridae). The mitochondrial diversity of these mosquitoes suggested that the Ae. aegypti population underwent a change that started in the second half of 2017, which coincides with the release of Wolbachia-infected mosquitoes in Medellín, indicating that the population of wMel-infected mosquitoes released has introduced new alleles into the wild Ae. aegypti population of Medellín. However, additional studies are required on the dispersal speed and intergenerational stability of wMel in Medellín and nearby areas as well as on the introgression of genetic variants in the native mosquito population.

Differential Hatching, Development, Oviposition, and Longevity Patterns among Colombian Aedes aegypti Populations.

Dengue, Zika, and chikungunya are arboviral diseases for which there are no effective therapies or vaccines. The only way to avoid their transmission is by controlling the vector Aedes aegypti, but insecticide resistance limits this strategy. To generate relevant information for surveillance and control mechanisms, we determined life cycle parameters, including longevity, fecundity, and mortality, of Colombian Ae. aegypti populations from four different geographical regions: Neiva, Bello, Itagüí, and Riohacha. When reared at 28 °C, Bello had the shortest development time, and Riohacha had the longest. Each mosquito population had its own characteristic fecundity pattern during four gonotrophic cycles. The survival curves of each population were significantly different, with Riohacha having the longest survival in both males and females and Bello the shortest. High mortality was observed in mosquitoes from Neiva in the egg stage and for Bello in the pupae stage. Finally, when mosquitoes from Neiva and Bello were reared at 35 °C, development times and mortality were severely affected. In conclusion, each population has a unique development pattern with an innate trace in their biological characteristics that confers vulnerability in specific stages of development.

Expansive and Diverse Phenotypic Landscape of Field Aedes aegypti (Diptera: Culicidae) Larvae with Differential Susceptibility to Temephos: Beyond Metabolic Detoxification.

Arboviruses including dengue, Zika, and chikungunya are amongst the most significant public health concerns worldwide. Arbovirus control relies on the use of insecticides to control the vector mosquito Aedes aegypti (Linnaeus), the success of which is threatened by widespread insecticide resistance. The work presented here profiled the gene expression of Ae. aegypti larvae from field populations of Ae. aegypti with differential susceptibility to temephos originating from two Colombian urban locations, Bello and Cúcuta, previously reported to have distinctive disease incidence, socioeconomics, and climate. We demonstrated that an exclusive field-to-lab (Ae. aegypti strain New Orleans) comparison generates an over estimation of differential gene expression (DGE) and that the inclusion of a geographically relevant field control yields a more discrete, and likely, more specific set of genes. The composition of the obtained DGE profiles is varied, with commonly reported resistance associated genes including detoxifying enzymes having only a small representation. We identify cuticle biosynthesis, ion exchange homeostasis, an extensive number of long noncoding RNAs, and chromatin modelling among the differentially expressed genes in field resistant Ae. aegypti larvae. It was also shown that temephos resistant larvae undertake further gene expression responses when temporarily exposed to temephos. The results from the sampling triangulation approach here contribute a discrete DGE profiling with reduced noise that permitted the observation of a greater gene diversity, increasing the number of potential targets for the control of insecticide resistant mosquitoes and widening our knowledge base on the complex phenotypic network of the Ae. aegypti response to insecticides.

Laboratory Evaluation and Field Feasibility of Micro-Encapsulated Insecticide Effect on Rhodnius prolixus and Triatoma dimidiata Mortality in Rural Households in Boyacá, Colombia

Abstract: Chagas disease is a neglected vector-borne zoonosis caused by the parasite Trypanosoma cruzi that is primarily transmitted by insects of the subfamily Triatominae. Although control efforts targeting domestic infestations of Rhodnius prolixus have been largely successful, with several regions in Boyacá department certified free of T. cruzi transmission by intradomicile R. prolixus, novel native species are emerging, increasing the risk of disease. Triatoma dimidiata is the second most important species in Colombia, and conventional control methods seem to be less effective. In this study we evaluated the efficacy and usefulness of micro-encapsulated insecticide paints in laboratory conditions and its applicability in rural communities to avoid triatomine domiciliation. Laboratory conditions measured mortality at 6 months and 12 months, with an average mortality between 93­100% for T. dimidiata and 100% for R. prolixus. Evaluation of triatomine infestation in rural households was measured after one year, with an overall perception of effectiveness in reducing household domiciliation. Although triatomines were still spotted inside and around the homes, our findings demonstrate the ability of micro-encapsulated insecticide to prevent colonization inside the households when comparing infestation rates from previous years. Current control measures suggest insecticide spraying every six months, which implies great economic cost and logistical effort. Complementary triatomine control measures with insecticide spraying and micro-encapsulated insecticide paint would make public health efforts more efficient and reduce the frequency of treatment.

Molecular surveillance of resistance to pyrethroids insecticides in Colombian Aedes aegypti populations.

INTRODUCTION: In Colombia, organochloride, organophosphate, carbamate, and pyrethroid insecticides are broadly used to control Aedes aegypti populations. However, Colombian mosquito populations have shown variability in their susceptibility profiles to these insecticides, with some expressing high resistance levels. MATERIALS AND METHODS: In this study, we analyzed the susceptibility status of ten Colombian field populations of Ae. aegypti to two pyrethroids; permethrin (type-I pyrethroid) and lambda-cyhalothrin (type-II pyrethroid). In addition, we evaluated if mosquitoes pressured with increasing lambda-cyhalothrin concentrations during some filial generations exhibited altered allelic frequency of these kdr mutations and the activity levels of some metabolic enzymes. RESULTS: Mosquitoes from all field populations showed resistance to lambda-cyhalothrin and permethrin. We found that resistance profiles could only be partially explained by kdr mutations and altered enzymatic activities such as esterases and mixed-function oxidases, indicating that other yet unknown mechanisms could be involved. The molecular and biochemical analyses of the most pyrethroid-resistant mosquito population (Acacías) indicated that kdr mutations and altered metabolic enzyme activity are involved in the resistance phenotype expression. CONCLUSIONS: In this context, we propose genetic surveillance of the mosquito populations to monitor the emergence of resistance as an excellent initiative to improve mosquito-borne disease control measures.