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Background: The collection of insects of medical importance from the Instituto Nacional de Salud, INS (Bogotá, Colombia: https://www.ins.gov.co/Paginas/Inicio.aspx), was started in 1934 with the aim of being an institutional and national repository of the biodiversity of insects involved in vector-borne diseases of importance in public health. Today, the entomological collection includes more than 7,500 specimens.The ceratopogonid insects are one group of Diptera that are represented in this collection. Within the Ceratopogonidae, the genus Culicoides Latreille, 1809 is relevant in public health because of the nuisance caused by their bites when they are presented in great abundance and because of their role as vectors of several agents (virus, protozoa and nematodes) that cause diseases to humans and to animals (Mellor et al. 2000, Mullen 2002). An overview of the Ceratopogonidae, represented in this collection, is presented here. A total of 801 individuals, mainly adults of the genus Culicoides (90%) are represented. The collection is the result of the effort of several researchers of the Group of Entomology at INS. These researchers collected ceratopogonids when they went to different transmission scenarios of vector-borne diseases in Colombia, with the purpose of making entomological characterisations including the processing, assembly and identification of the specimens in the laboratory. New information: New information about the geographical distribution of 39 species of the genus Culicoides in Colombia. All data have been uploaded to GBIF and are publicly available there.

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Aedes aegypti mosquitoes are the main vector of human arbovirosis in tropical and subtropical areas. Their adaptation to urban and rural environments generates infestations inside households. Therefore, entomological surveillance associated with spatio-temporal analysis is an innovative approach for vector control and dengue management. Here, our main aim was to inspect immature pupal stages in households belonging to municipalities at high risk of dengue in Cauca, Colombia, by implementing entomological indices and relating how they influence adult mosquitos' density. We provide novel data for the geographical distribution of 3,806 immature pupal stages of Ae. aegypti. We also report entomological indices and spatial characterization. Our results suggest that, for Ae. aegypti species, pupal productivity generates high densities of adult mosquitos in neighbouring households, evidencing seasonal behaviour. Our dataset is essential as it provides an innovative strategy for mitigating vector-borne diseases using vector spatial patterns. It also delineates the association between these vector spatial patterns, entomological indicators, and breeding sites in high-risk neighbourhoods.

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This study used the geostatistical Kriging methodology to reduce the spatial scale of a host of daily meteorological variables in the Department of Cauca (Colombia), namely, total precipitation and maximum, minimum, and average temperature. The objective was to supply a high-resolution database from 01/01/2015 to 31/12/2021 in order to support the climate component in a project led by the National Institute of Health (INS) named "Spatial Stratification of dengue based on the identification of risk factors: a pilot study in the Department of Cauca". The scaling process was applied to available databases from satellite information and reanalysis sources, specifically, CHIRPS (Climate Hazards Group InfraRed Precipitation with Station Data), ERA5-Land (European Centre for Medium-Range Weather Forecasts), and MSWX (Multi-Source Weather). The 0.1° resolution offered by both the MSWX and ERA5-Land databases and the 0.05° resolution found in CHIRPS, was successfully reduced to a scale of 0.01° across all variables. Statistical metrics such as Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), Person Correlation Coefficient (r), and Mean Bias Error (MBE) were used to select the database that best estimated each variable. As a result, it was determined that the scaled ERA5-Land database yielded the best performance for precipitation and minimum daily temperature. On the other hand, the scaled MSWX database showed the best behavior for the other two variables of maximum temperature and daily average temperature. Additionally, using the scaled meteorological databases improved the performance of the regression models implemented by the INS for constructing a dengue early warning system.

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Dengue is an arbovirus transmitted by mosquitoes of the genus Aedes and is one of the 15 main public health problems in the world, including Colombia. Where limited financial resources create a problem for management, there is a need for the department to prioritize target areas for public health implementation. This study focuses on a spatio-temporal analysis to determine the targeted area to manage the public health problems related to dengue cases. To this end, three phases at three different scales were carried out. First, for the departmental scale, four risk clusters were identified in Cauca (RR ≥ 1.49) using the Poisson model, and three clusters were identified through Getis-Ord Gi* hotspots analysis; among them, Patía municipality presented significantly high incidence rates in the time window (2014-2018). Second, on the municipality scale, altitude and minimum temperature were observed to be more relevant than precipitation; considering posterior means, no spatial autocorrelation for the Markov Chain Monte Carlo was found (Moran test ˂ 1.0), and convergence was reached for b1-b105 with 20,000 iterations. Finally, on the local scale, a clustered pattern was observed for dengue cases distribution (nearest neighbour index, NNI = 0.202819) and the accumulated number of pupae (G = 0.70007). Two neighbourhoods showed higher concentrations of both epidemiological and entomological hotspots. In conclusion, the municipality of Patía is in an operational scenario of a high transmission of dengue.

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The Culicidae family has two of the most important disease vector genus: Aedes spp. and Culex spp. Both of these are involved in the transmission of arboviruses. Here, we provide novel data for the geographical distribution of 2,383 specimens in the Culicidae family. We also report the percentage of houses infested with these vectors, and Shannon and Simpson diversity indices in three municipalities located in Cauca, Colombia. This dataset is relevant for research on vector-borne diseases because Aedes spp. can transmit arboviruses such as dengue, Zika and chikungunya, and Culex spp. is a well-known vector of West Nile virus and Venezuelan equine encephalitis.

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BACKGROUND: Long lasting insecticide-treated nets (LLINs) may be effective for vector control of cutaneous leishmaniasis (CL). Their efficacy, however, has not been sufficiently evaluated. OBJECTIVE: To evaluate the large-scale efficacy of LLINs on Lutzomyia longiflocosa entomological parameters up to two years post-intervention in the sub-Andean region of Colombia. METHODS: A matched-triplet cluster-randomised study of 21 rural settlements, matched by pre-intervention L. longiflocosa indoor density was used to compare three interventions: dip it yourself (DIY) lambda-cyhalothrin LLIN, deltamethrin LLIN, and untreated nets (control). Sand fly indoor density, feeding success, and parity were recorded using CDC light trap collections at 1, 6, 12, and 24 months post-intervention. FINDINGS: Both LLINs reduced significantly (74-76%) the indoor density and the proportion of fully engorged sand flies up to two years post-intervention without differences between them. Residual lethal effects of both LLINs and the use of all nets remained high throughout the two-year evaluation period. CONCLUSIONS: Both LLINs demonstrated high efficacy against L. longiflocosa indoors. Therefore, the deployment of these LLINs could have a significant impact on the reduction of CL transmission in the sub-Andean region. The DIY lambda-cyhalothrin kit may be used to convert untreated nets to LLINs increasing coverage.

Assuntos

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After the first autochthonous case of cutaneous leishmaniasis was reported in the Atlántico department in the Caribbean region of Colombia, entomological sampling was conducted in the specific areas where the infection might have occurred. CDC traps were installed inside and outside dwellings in the peri-urban and rural areas of a settlement in the municipality of Luruaco. Sampling was performed during the night with protected human bait, and phlebotomine sand flies were actively sampled from potential diurnal resting sites within dwellings. Ten species of the genus Lutzomyia were identified; Lutzomyia evansi was the dominant species (78%) in the rural and peri-urban areas as well as in the different sampled habitats, followed by Lutzomyia panamensis and Lutzomyia gomezi. There was a 100% household infestation by Lu. evansi, and its indoor mean abundance was 13.3 sand flies/CDC trap/night. The indoor mean abundance of Lu. panamensis and Lu. gomezi was only 0.9 and 0.8 sand flies/CDC trap/night, respectively. Female Lu. evansi were collected with protected human bait, mostly in the peridomestic area, with sustained activity during the night and a slight increase in the activity from 19:00 to 23:00 hours. Of the total sand flies captured in the diurnal resting sites, 73.1% were collected from the walls of bedrooms and corresponded to Lu. evansi, Lutzomyia cayennensis cayennensis, and Lutzomyia trinidadensis. Owing to their vectorial importance, the species on which entomological surveillance should be focused are Lu. evansi, Lu. panamensis, and Lu. gomezi. The biting and resting behavior reported in this study will help guide vector prevention and the control of leishmaniasis within the study area.

Assuntos

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Fitting long-lasting insecticidal nets (LLIN) as screens on doors/windows has a significant impact on indoor-adult Aedes aegypti (L.), with entomological reductions measured in a previous study being significant for up to 2 yr post-installation, even in the presence of pyrethroid-resistant Aedes populations. To better understand the mode of LLIN protection, bioassays were performed to evaluate the effects of field deployment (0, 6, and 12 mo) and damage type (none, central, lateral, and multiple) on LLIN efficacy. Contact bioassays confirmed that LLIN residual activity (median knockdown time, in minutes, or MKDT) decreased significantly over time: 6.95 (95% confidence interval [CI]: 5.32-8.58) to 9.24 (95% CI: 8.69-9.79) MKDT at 0- and 12-mo age, respectively, using a pyrethroid-susceptible Aedes strain. Tunnel tests (exposing human forearm for 40 min as attractant) showed that deployment time affected negatively Aedes passage inhibition from 54.9% (95% CI: 43.5-66.2) at 0 mo to 35.7% (95% CI: 16.3-55.1) at 12 mo and blood-feeding inhibition from 65.2% (95% CI: 54.2-76.2) to 48.9% (95% CI: 26.4-71.3), respectively; both the passage/blood-feeding inhibition increased by a factor of 1.8-2.9 on LLINs with multiple and central damages compared with nets with lateral damage. Mosquito mortality was 74.6% (95% CI: 65.3-83.9) at 0 mo, 72.3% (95% CI: 64.1-80.5) at 6 mo, and 59% (95% CI: 46.7-71.3) at 12 mo. Despite the LLIN physical integrity could be compromised over time, we demonstrate that the remaining chemical effect after field conditions would still contribute to killing/repelling mosquitoes.

Assuntos

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BACKGROUND Long lasting insecticide-treated nets (LLINs) may be effective for vector control of cutaneous leishmaniasis (CL). Their efficacy, however, has not been sufficiently evaluated. OBJECTIVE To evaluate the large-scale efficacy of LLINs on Lutzomyia longiflocosa entomological parameters up to two years post-intervention in the sub-Andean region of Colombia. METHODS A matched-triplet cluster-randomised study of 21 rural settlements, matched by pre-intervention L. longiflocosa indoor density was used to compare three interventions: dip it yourself (DIY) lambda-cyhalothrin LLIN, deltamethrin LLIN, and untreated nets (control). Sand fly indoor density, feeding success, and parity were recorded using CDC light trap collections at 1, 6, 12, and 24 months post-intervention. FINDINGS Both LLINs reduced significantly (74-76%) the indoor density and the proportion of fully engorged sand flies up to two years post-intervention without differences between them. Residual lethal effects of both LLINs and the use of all nets remained high throughout the two-year evaluation period. CONCLUSIONS Both LLINs demonstrated high efficacy against L. longiflocosa indoors. Therefore, the deployment of these LLINs could have a significant impact on the reduction of CL transmission in the sub-Andean region. The DIY lambda-cyhalothrin kit may be used to convert untreated nets to LLINs increasing coverage.

Assuntos

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ABSTRACT The study aimed to determine the toxicity of lambda-cyhalothrin, alpha-cypermethrin, and deltamethrin in L. longipalpis, through concentration-mortality bioassays. The test here was performed following WHO guidelines, but instead of using exposure WHO recipients and impregnated papers, 250 ml Wheaton glass bottles treated with 1 ml of insecticide solution were used. Batches of ten females of L. longipalpis were exposed to five concentrations of each pyrethroid that caused between 5 and 100 % mortality in this species. After 1 h of exposure, the females were transferred to observation recipients, and mortality was recorded 24 h later. The lethal concentrations (g/ml) that killed 50 and 95 % (LC50 and LC95) of the exposed L. longipalpis females were 0.05 and 0.86 for lambda-cyhalothrin, 0.24 and 3.62 for alpha-cypermethrin and 0.53 and 4.72 for deltamethrin. Based on the LC50 obtained, lambda-cyhalothrin is the most toxic pyrethroid for L. longipalpis, followed by alpha-cypermethrin and deltamethrin. It is expected that these data may be useful in studies on the effects of sub-lethal concentrations of the three pyrethroids on the behavior of L. longipalpis and studies on the vector susceptibility to these pyrethroids.

RESUMEN El objetivo del estudio fue determinar la toxicidad de los piretroides lambdacialotrina, deltametrina y alfacipermetrina en L. longipalpis, a través de ensayos concentración-mortalidad. Los ensayos se hicieron siguiendo los lineamientos de la OMS, pero en lugar de los recipientes de exposición y de los papeles impregnados de la OMS, se utilizaron botellas de vidrio Wheaton de 250 ml tratadas con 1 ml de solución de insecticida en alcohol absoluto. Grupos de 10 hembras de L. longipalpis sin alimentación sanguínea fueron expuestos a cinco concentraciones de cada piretroide, que causaron entre el 5 y 100 % de mortalidad. Pasada una hora de exposición, las hembras se trasladaron a los recipientes de observación y la mortalidad se registró 24 h después. Las concentraciones (g/ml) que mataron el 50 y el 95 % (CL50 y CL95) de las hembras expuestas de L. longipalpis fueron de 0,05 y 0,86 para la lambdacialotrina, 0,24 y 3,62 para la alfacipermetrina y 0,53 y 4,72 para la deltametrina. Basados en las CL50 obtenidas, la lambdacialotrina fue el piretroide con mayor toxicidad para L. longipalpis, seguido por la alfacipermetrina y la deltametrina. Se espera que estos datos puedan ser útiles en estudios de los efectos de concentraciones sub-letales de los tres piretroides en el comportamiento de L. longipalpis y en estudios de la susceptibilidad del vector a los mismos.