Causal association between environmental variables and the excess cases of cutaneous leishmaniasis in Colombia: are we looking to the wrong side?

Our main aim was to estimate and compare the effects of six environmental variables (air temperature, soil temperature, rainfall, runoff, soil moisture, and the enhanced vegetation index) on excess cases of cutaneous leishmaniasis in Colombia. We used epidemiological data from the Colombian Public Health Surveillance System (January 2007 to December 2019). Environmental data were obtained from remote sensing sources including the National Oceanic and Atmospheric Administration, the Global Land Data Assimilation System (GLDAS), and the Moderate Resolution Imaging Spectroradiometer. Data on population were obtained from the TerriData dataset. We implemented a causal inference approach using a machine learning algorithm to estimate the causal association of the environmental variables on the monthly occurrence of excess cases of cutaneous leishmaniasis. The results showed that the largest causal association corresponded to soil moisture with a lag of 3 months, with an average increase of 8.0% (95% confidence interval [CI] 7.7-8.3%) in the occurrence of excess cases. The temperature-related variables (air temperature and soil temperature) had a positive causal effect on the excess cases of cutaneous leishmaniasis. It is noteworthy that rainfall did not have a statistically significant causal effect. This information could potentially help to monitor and control cutaneous leishmaniasis in Colombia, providing estimates of causal effects using remote sensor variables.

Similarity but not equivalence: Ecological niche comparison between sandflies from the Pleistocene and future scenarios in Central and South America.

Sandfly species (Diptera: Psychodidae) are suspected or proven vectors of Leishmania spp. in the American region. Understanding niche conservatism (NC) in insect vectors allows an understanding of constraints on adaptive responses, and thus implications for disease ecology. Therefore, in this study, the authors evaluated NC in three vector species of leishmaniasis (Lutzomyia gomezi, Psathyromyia shannoni and Pintomyia ovallesi) in Central and South America. For this, the authors performed niche identity and similarity testing through paired comparisons in ENMTools and niche overlap in Niche Analyst. The authors found that species niches were more similar to each other than if the points had been randomly extracted, and they also found extensive similarity between Pa. shannoni and Lu. gomezi niches and in Pa. shannoni niches over different timescales. The authors suggest Pa. shannoni as a priority species due to fundamental niche similarity with phylogenetically related species and also its extensive evolutionary history and ecological plasticity that could affect the emergence and resurgence of leishmaniasis in areas endemic by this vector.

Modeling potential risk areas of Orthohantavirus transmission in Northwestern Argentina using an ecological niche approach.

BACKGROUND: Hantavirus Pulmonary Syndrome (HPS) is a rodent-borne zoonosis in the Americas, with up to 50% mortality rates. In Argentina, the Northwestern endemic area presents half of the annually notified HPS cases in the country, transmitted by at least three rodent species recognized as reservoirs of Orthohantavirus. The potential distribution of reservoir species based on ecological niche models (ENM) can be a useful tool to establish risk areas for zoonotic diseases. Our main aim was to generate an Orthohantavirus risk transmission map based on ENM of the reservoir species in northwest Argentina (NWA), to compare this map with the distribution of HPS cases; and to explore the possible effect of climatic and environmental variables on the spatial variation of the infection risk. METHODS: Using the reservoir geographic occurrence data, climatic/environmental variables, and the maximum entropy method, we created models of potential geographic distribution for each reservoir in NWA. We explored the overlap of the HPS cases with the reservoir-based risk map and a deforestation map. Then, we calculated the human population at risk using a census radius layer and a comparison of the environmental variables' latitudinal variation with the distribution of HPS risk. RESULTS: We obtained a single best model for each reservoir. The temperature, rainfall, and vegetation cover contributed the most to the models. In total, 945 HPS cases were recorded, of which 97,85% were in the highest risk areas. We estimated that 18% of the NWA population was at risk and 78% of the cases occurred less than 10 km from deforestation. The highest niche overlap was between Calomys fecundus and Oligoryzomys chacoensis. CONCLUSIONS: This study identifies potential risk areas for HPS transmission based on climatic and environmental factors that determine the distribution of the reservoirs and Orthohantavirus transmission in NWA. This can be used by public health authorities as a tool to generate preventive and control measures for HPS in NWA.

Spatial fine-resolution model of malaria risk for the Colombian Pacific region.

OBJECTIVE: To categorise and map, at high resolution, the risk of malaria incidence in the Pacific region, the main malaria-endemic region of Colombia. METHODS: The relationship between the environmental variables Normalized Difference Vegetation Index Normalized Difference Water Index, Topographic Wetness Index, precipitation and temperature with the observed Annual Parasitic Index was evaluated using a generalised linear model. An incidence risk map at a resolution of 1 km2 was constructed and projected to the entire endemic region. Associations of malaria risk categories with both presence records and co-occurrence of the three main malaria vectors were determined. RESULTS: A significant correlation was found for the incidence of malaria with precipitation and Normalized Difference Vegetation Index (R2  = 0.98, P < 0.05), whereas there was no significant correlation with the remaining environmental and topographic variables. Moderate- to high-risk areas were located mainly in central Chocó Department along the San Juan and Atrato rivers and in areas west of the Cauca River and Pacific lowlands of the Andes Mountains. There was a statistically significant relationship for the presence of the two main vectors Anopheles darlingi and Anopheles nuneztovari with the high malaria risk category. Furthermore, malaria risk was directly proportional to the number of co-occurring vector species. CONCLUSIONS: The map obtained provides useful information on the risk of malaria in particular places of the Colombian Pacific region. The data can be used by public entities to optimise the allocation of economic resources for vector control interventions and surveillance.

OBJECTIF: Classifier et cartographier, à haute résolution, le risque d'incidence du paludisme dans la région du Pacifique, la principale région de Colombie où le paludisme est endémique. MÉTHODES: La relation entre les variables environnementales, l'Indice de différence de végétation normalisée, l'Indice différence hydrique normalisée, l'Indice d'humidité topographique, les précipitations et la température avec l'indice parasitique annuel observé a été évaluée à l'aide d'un modèle linéaire généralisé. Une carte des risques d'incidence à une résolution de 1 km2 a été construite et projetée sur l'ensemble de la région endémique. Les associations des catégories de risque de paludisme avec les deux, les registres de présence et la co-occurrence des trois principaux vecteurs du paludisme ont été déterminées. RÉSULTATS: Une corrélation significative a été trouvée pour l'incidence du paludisme avec les précipitations et l'indice de différence de végétation normalisée (R2  = 0,98 ; P < 0,05), alors qu'il n'y avait pas de corrélation significative avec les autres variables environnementales et topographiques. Les zones de risque modéré à élevé étaient principalement situées dans le département central du Chocó, le long des rivières San Juan et Atrato, et dans les zones à l'ouest de la rivière Cauca et des basses régions Pacifiques de la Cordillère des Andes. Il y avait une relation statistiquement significative entre la présence des deux principaux vecteurs Anopheles darlingi et Anopheles nuneztovari et la catégorie à haut risque de paludisme. De plus, le risque de paludisme était directement proportionnel au nombre d'espèces de vecteurs co-occurrents. CONCLUSIONS: La carte obtenue fournit des informations utiles sur le risque de paludisme dans des endroits particuliers de la région Pacifique de la Colombie. Les données peuvent être utilisées par les entités publiques pour optimiser l'allocation des ressources économiques pour les interventions de lutte contre les vecteurs et la surveillance.

Potential distribution of main malaria vector species in the endemic Colombian Pacific region.

OBJECTIVE: To assess the existing fundamental niche, potential distribution and degree of niche overlap for the three main Colombian malaria vectors Anopheles albimanus, Anopheles darlingi and Anopheles nuneztovari in the major malaria endemic Pacific region. METHODS: We used models based on presence records and Normalised Difference Vegetation Index (NDVI) data, created using the maximum entropy algorithm. RESULTS: The three vector species occupied heterogeneous environments, and their NDVI values differed. Anopheles albimanus had the largest niche amplitude and was distributed mainly on coastal areas. Environmentally suitable areas for An. albimanus and An. nuneztovari were the dry forest of inter-Andean Valleys in south-western Colombia, as confirmed for An. albimanus during model validation. There was a slight degree of niche overlap between An. darlingi and An. nuneztovari, and the species co-occurred in humid forests, predominantly in riparian zones of the San Juan and Atrato rivers. CONCLUSION: The information obtained may be used for the implementation of vector control interventions in selected priority areas to reduce malaria risk in this region while optimising resources.

OBJECTIF: Evaluer la niche fondamentale existante, la distribution potentielle et le degré de superposition de niches pour les trois principaux vecteurs colombiens du paludisme: Anopheles albimanus, Anopheles darlingi et Anopheles nuneztovari, dans la principale région endémique du Pacifique pour le paludisme. MÉTHODES: Nous avons utilisé des modèles basés sur des enregistrements de présence et des données de Différence Normalisée d'Indice de Végétation par (NDVI), créés à l'aide de l'algorithme d'entropie maximale. RÉSULTATS: Les trois espèces vectorielles occupaient des environnements hétérogènes et leurs valeurs NDVI différaient. Anopheles albimanus avait la plus grande amplitude de niche et était distribué principalement sur les zones côtières. Les zones convenables environnementalement pour An. albimanus et An. nuneztovari était la forêt sèche des vallées inter-andines du sud-ouest de la Colombie, telles que confirmées pour An. albimanus lors de la validation du modèle. Il y avait un léger degré de superposition de niches entre An. darlingi et An. nuneztovari et les espèces coexistaient dans les forêts humides, principalement dans les zones riveraines des fleuves San Juan et Atrato. CONCLUSION: Les informations obtenues peuvent être utilisées pour la mise en œuvre d'interventions de lutte antivectorielle dans certaines zones prioritaires afin de réduire le risque de paludisme dans cette région tout en optimisant les ressources.

Downscaling incidence risk mapping for a Colombian malaria endemic region.

OBJECTIVE: To map at a fine spatial scale, the risk of malaria incidence for the important endemic region is Urabá-Bajo Cauca and Alto Sinú, NW Colombia, using a new modelling framework based on GIS and remotely sensed environmental data. METHODS: The association between environmental and topographic variables obtained from remote sensors and the annual parasite incidence (API) for the years 2013-2015 was calculated using multiple regression analysis; subsequently, a model was constructed to estimate the API and to project it to the entire endemic region in order to design the risk map. The model was validated by relating the obtained API values with the presence of the three main Colombian malaria vectors, Anopheles darlingi, Anopheles albimanus and Anopheles nuneztovari. RESULTS: Temperature and Normalized Difference Water Index (NDWI) showed a significant correlation with the observed API. The risk map of malaria incidence showed that the zones at higher risk in the Urabá-Bajo Cauca and Alto Sinú region were located south-east of the region, while the northern area presented the lowest malaria risk. A method was generated to estimate the API for small urban centres, instead of the used reports at the municipality level. CONCLUSIONS: These results provide evidence of the utility of risk maps to identify environmentally vulnerable areas at a fine spatial resolution in the Urabá-Bajo Cauca and Alto Sinú region. This information contributes to the implementation of vector control interventions at the microgeographic scale at areas of high malaria risk.

The effect of El Niño and La Niña episodes on the existing niche and potential distribution of vector and host species of American Cutaneous Leishmaniasis.

Leishmaniasis is a zoonotic disease transmitted to humans by a protozoan parasite through sandfly vectors and multiple vertebrate hosts. The Pan American Health Organization reported a declining trend in cases, with Brazil, Colombia, Peru, Nicaragua, and Bolivia having the most cases in 2020. There are still knowledge gaps in transmission and the parasite-host relationship. Ecological niche modeling has been used to study host-vector relationships, disease dynamics, and the impact of climate change. Understanding these aspects can aid in early surveillance and vector control strategies. The potential distribution of five host species associated with the transmission of cutaneous leishmaniasis (CL) was modeled. Occurrence data were collected for each host species, and environmental variables were used to build the models. Climatic data from El Niño, La Niña, and Neutral episodes were used to compare the predicted distributions. Additionally, the potential distributions of four vector species were compared to identify overlaps with host species. Niche analysis was conducted to evaluate changes in vector niches across episodes and to identify host-vector pairs based on niche overlap in geographic and environmental spaces. After spatial thinning, 467 records were obtained, and 1,190 candidate models were evaluated for each species. Results showed the distribution of occurrences in the environmental space, highlighting a high risk of extrapolation beyond the calibration areas. Movement-Oriented Parity analysis revealed distinct distribution patterns under different climate conditions, with areas of environmental similarity identified. Bradypus variegatus exhibited a broad potential distribution, while Dasypus novemcinctus and Didelphis marsupialis had more restricted ranges. Sylvilagus braziliensis covered most of the Neotropics. Our study provides valuable insights into ecological niches and geographic ranges of these species, contributing to the understanding of cutaneous leishmaniasis transmission dynamics.

Effect of environmental variables on the incidence of Visceral Leishmaniasis in Brazil and Colombia.

Visceral Leishmaniasis (VL) is the most severe of the three forms of Leishmaniasis. In the Americas, Brazil and Colombia present more than 90 % of the cases in the region. Our aim in this research was to estimate the association of the incidence rate of Visceral Leishmaniasis with the following environmental variables: the percentage of area suitable for the vector Lutzomyia longipalpis, the episodes of La Niña and El Niño, the Brazilian and Colombian biomes. Epidemiological data were obtained from the Brazilian Notifiable Diseases Information System and the Colombian National Public Health Surveillance System. Environmental data were downloaded from the NASA Giovanni web app, the Modis Sensor database, and the meteorological agencies of Australia, Japan, and the United States of America. Records of the presence of Lu. longipalpis were obtained from public databases and previous studies. As a result, the incidence per 10,000 inhabitants with LEBS for each El Niño-Southern Oscillation (ENSO) episode showed the largest values during El Niño 2015-2016, mainly in Brazil's Northeast and Central regions and the Northeast region of Colombia. Compared with the Neutral 2012-2014 episode, the episodes of El Niño 2015-2016 and La Niña 2010-2011 showed an average increase in the monthly incidence rate of VL, and the average increase was higher during El Niño 2015-2016 (aIRR = 2.304 vs.1.453) We found a positive association between the incidence rate of VL and the El Niño 2015-2016 episode and an impressive% of area suitable for the vector Lu. longipalpis in the Amazon region.An increase of 1 % in the area suitable for the vector Lu. longipalpis leads to an average rise of 0.8 % in the monthly incidence rate of VL. Our study shows a possible association between VL incidence and ENSO, with the most considerable incidence rates observed during El Niño 2015-2016 in Brazil's Northeast and Central regions and the Northeast region of Colombia. The present study is very important to better understand the Visceral Leishmaniasis transmission dynamics.

Incidence of the El Niño-Southern Oscillation Cycle on the Existing Fundamental Niche and Establishment Risk of Some Anastrepha Species (Diptera-Tephritidae) of Horticultural Importance in the Neotropics and Panama.

To compare the environmental space of four Anastrepha species in different ENSO episodes (El Niño, El Neutro and La Niña), we built ecological niche models with NicheA software. We analysed the fundamental niche and the combined establishment risk maps of these species developed with the ArcGisPro combine geoprocess. A comparison of the ellipsoids that represent the fundamental niche existing for the species showed changes in the El Niño, El Neutro and La Niña episodes. For A. grandis in the El Niño vs. El Neutro episodes, there was a Jaccard index of 0.3841, while the comparison between the La Niña vs. El Neutro episodes presented a Jaccard index of 0.6192. A. serpentina in the El Niño vs. El Neutro and La Niña vs. El Neutro episodes presented Jaccard indices of 0.3281 and 0.6328, respectively. For A. obliqua, the comparison between the El Niño vs. El Neutro and La Niña vs. El Neutro episodes presented Jaccard indices of 0.3518 and 0.7472, respectively. For A. striata, comparisons between the episodes of El Niño vs. El Neutro and La Niña vs. El Neutro presented Jaccard indices of 0.3325 and 0.6022, respectively. When studying the comparison between Anastrepha species and the different ENSO climatic episodes, we found that in the El Niño episode, the comparisons with the best environmental similarity were A. obliqua vs. A. striata and A. obliqua vs. A. serpentina, with higher Jaccard indices (0.6064 and 0.6316, respectively). In the El Neutro episode, the comparisons with the best environmental similarity were A. serpentina vs. A. striata and A. obliqua vs. A. striata, which presented higher Jaccard indices (0.4616 and 0.6411, respectively). In the La Niña episode, the comparisons that presented the best environmental similarity were A. obliqua vs. A. serpentina and A. obliqua vs. A. striata, with higher Jaccard indices (0.5982 and 0.6228, respectively). Likewise, our results present the risk maps for the establishment of these species throughout the Neotropics, allowing us to predict the level of risk in order to develop integrated pest management plans.

Identifying Areas of Invasion Risk and Changes in the Ecological Niche Occupied by the Coffee Leaf Miner Leucoptera coffeella (Lepidoptera: Lyonetiidae).

Insects of economic importance such as Leucoptera coffeella can cause high defoliation in plants and reduce crop yields. We aimed to identify changes in the ecological niche and potential zones of the invasion. Occurrence records were obtained from databases and bibliography. WorldClim V2.0 bioclimatic layers were used. For the modeling of the potential distribution, the kuenm R package was used by executing the Maxent algorithm. The potential distribution models suggested greatest environmental suitability extends from Europe, South Asia, and Central and South Africa, showing the "tropical and subtropical moist broadleaf forests" as the ecoregion that presents the greatest probability of the presence of L. coffeella. The potential distribution model projected in the invaded area agrees with the known distribution in the region (America), although the results show that it is occupying environmental spaces not present in the area of origin. This species presented a large proportion of the invaded niche that overlaps the native niche and is colonizing new environmental conditions in the invaded area relative to its native distribution (Africa). This information could be used in the planning of coffee crops on the American continent.

Predicting the potential distribution and coexistence of Chagas disease vectors in the Americas.

Predicting the potential distribution and coexistence of suitable geographic areas for Chagas disease vectors in the Americas is a crucial task for understanding the eco-epidemiological dynamics of this disease. The potential distribution and coexistence of 3 species-Rhodnius prolixus (Hemiptera: Reduviidae), Cavernicola pilosa (Hemiptera: Reduviidae), and Rhodnius pictipes (Hemiptera: Reduviidae) were modeled. Presence records were obtained and environmental variables were selected based on correlation analysis, Jackknife analysis and knowledge of the biology and natural history of the species. The MaxEnt algorithm included in the kuenm package of R software was used for modeling the potential distribution, and various scenarios of the BAM diagram (Biotic, Abiotic, and Movement variables) were evaluated. The variables contributing to the final models were different for each species. Rhodnius pictipes showed a potential distribution in South America, particularly in Brazil, Bolivia, Peru, Colombia, Venezuela, Guyana, and Suriname. Areas with environmentally suitable conditions for R. prolixus were located in southern Brazil, Peru, Colombia, southern Mexico, Guatemala, El Salvador, and Honduras, whereas for C. pilosa they were in southeastern Brazil, southeastern Central America, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, and French Guiana. Co-occurrence analysis revealed distinct patterns in the neotropical region, with some areas indicating the potential distribution of 1 or more species. In Brazil, occurrence and co-occurrence areas were concentrated in the northwest and southeast regions. Overall, this study provides valuable information on the potential distribution and coexistence of vectors, which can inform targeted vector control strategies and contribute to global efforts in combating Chagas disease.

Entomological parameters and population structure at a microgeographic scale of the main Colombian malaria vectors Anopheles albimanus and Anopheles nuneztovari.

Population subdivision among several neotropical malaria vectors has been widely evaluated; however, few studies have analyzed population variation at a microgeographic scale, wherein local environmental variables may lead to population differentiation. The aim of the present study was to evaluate the genetic and geometric morphometric structure of Anopheles nuneztovari and Anopheles albimanus in endemic localities of northwestern Colombia. Genetic and phenetic structures were evaluated using microsatellites markers and wing geometric morphometrics, respectively. In addition, entomological indices of importance in transmission were calculated. Results showed that the main biting peaks of Anopheles nuneztovari were between 20:00 and 22:00, whereas Anopheles albimanus exhibited more variation in biting times among localities. Infection in An. nuneztovari by Plasmodium spp. (IR: 4.35%) and the annual entomological inoculation rate (30.31), indicated high vector exposure and local transmission risk. We did not detect Plasmodium-infected An. albimanus in this study. In general, low genetic and phenetic subdivision among the populations of both vectors was detected using a combination of phenotypic, genetic and environmental data. The results indicated high regional gene flow, although local environmental characteristics may be influencing the wing conformation differentiation and behavioral variation observed in An. albimanus. Furthermore, the population subdivision detected by microsatellite markers for both species by Bayesian genetic analysis provides a more accurate picture of the current genetic structure in comparison to previous studies. Finally, the biting behavior variation observed for both vectors among localities suggests the need for continuous malaria vector surveys covering the endemic region to implement the most effective integrated local control interventions.

Evaluation of the Effect of the ENSO Cycle on the Distribution Potential of the Genus Anastrepha of Horticultural Importance in the Neotropics and Panama.

Climate variability has made us change our perspective on the study of insect pests and pest insects, focusing on preserving or maintaining efficient production systems in the world economy. The four species of the genus Anastrepha were selected for this study due to their colonization and expansion characteristics. Models of the potential distribution of these species are scarce in most neotropical countries, and there is a current and pressing demand to carry out this type of analysis in the face of the common scenarios of climate variability. We analyzed 370 presence records with statistical metrics and 16 bioclimatic variables. The MaxEnt method was used to evaluate the effect of the ENSO cycle on the potential distribution of the species Anastrepha grandis (Macquart), Anastrepha serpetina (Wiedemann), Anastrepha obliqua (Macquart), and Anastrepha striata (Schiner) as imported horticultural pests in the neotropics and Panama. A total of 3472 candidate models were obtained for each species, and the environmental variables with the greatest contribution to the final models were LST range and LST min for A. grandis, PRECIP range and PRECIP min for A. serpentina, LST range and LST min for A. obliqua, and LST min and LST max for A. striata. The percentage expansion of the range of A. grandis in all environmental scenarios was 26.46 and the contraction of the range was 30.80; the percentage expansion of the range of A. serpentina in all environmental scenarios was 3.15 and the contraction of the range was 28.49; the percentage expansion of the range of A. obliqua in all environmental scenarios was 5.71 and the contraction of the range was 3.40; and the percentage expansion of the range of A. striata in all environmental scenarios was 41.08 and the contraction of the range was 7.30, and we selected the best model, resulting in a wide distribution (suitable areas) of these species in the neotropics that was influenced by the variability of climatic events (El Niño, Neutral, and La Niña). Information is provided on the phytosanitary surveillance systems of the countries in areas where these species could be established, which is useful for defining policies and making decisions on integrated management plans according to sustainable agriculture.

Time lag effect on malaria transmission dynamics in an Amazonian Colombian municipality and importance for early warning systems.

Malaria remains a significant public health problem worldwide, particularly in low-income regions with limited access to healthcare. Despite the use of antimalarial drugs, transmission remains an issue in Colombia, especially among indigenous populations in remote areas. In this study, we used an SIR Ross MacDonald model that considered land use change, temperature, and precipitation to analyze eco epidemiological parameters and the impact of time lags on malaria transmission in La Pedrera-Amazonas municipality. We found changes in land use between 2007 and 2020, with increases in forested areas, urban infrastructure and water edges resulting in a constant increase in mosquito carrying capacity. Temperature and precipitation variables exhibited a fluctuating pattern that corresponded to rainy and dry seasons, respectively and a marked influence of the El Niño climatic phenomenon. Our findings suggest that elevated precipitation and temperature increase malaria infection risk in the following 2 months. The risk is influenced by the secondary vegetation and urban infrastructure near primary forest formation or water body edges. These results may help public health officials and policymakers develop effective malaria control strategies by monitoring precipitation, temperature, and land use variables to flag high-risk areas and critical periods, considering the time lag effect.

Would Climate Change Influence the Potential Distribution and Ecological Niche of Bluetongue Virus and Its Main Vector in Peru?

Bluetongue virus (BTV) is an arbovirus that is transmitted between domestic and wild ruminants by Culicoides spp. Its worldwide distribution depends on competent vectors and suitable environmental ecosystems that are becoming affected by climate change. Therefore, we evaluated whether climate change would influence the potential distribution and ecological niche of BTV and Culicoides insignis in Peru. Here, we analyzed BTV (n = 145) and C. insignis (n = 22) occurrence records under two shared socioeconomic pathway scenarios (SSP126 and SSP585) with five primary general circulation models (GCMs) using the kuenm R package v.1.1.9. Then, we obtained binary presence-absence maps and represented the risk of transmission of BTV and niche overlapping. The niche model approach showed that north and east Peru presented suitability in the current climate scenario and they would have a decreased risk of BTV, whilst its vector would be stable and expand with high agreement for the five GCMs. In addition, its niche overlap showed that the two niches almost overlap at present and would completely overlap with one another in future climate scenarios. These findings might be used to determine the areas of highest priority for entomological and virological investigations and surveillance in order to control and prevent bluetongue infections in Peru.

Characterization of Feeding Behavior and its Relationship With the Longevity of Wild and Peridomestic Triatoma dimidiata, Latreille 1811 (Hemiptera, Reduviidae) Under Laboratory Conditions.

Triatoma dimidiata (Latreille 1811) is considered the second most important vector of the Trypanosa cruzi etiological agent of Chagas disease in Colombia. It has a life cycle that involves a domiciled, peridomiciled, and wild distribution. The study of feeding behavior and its influence on the survival of sylvatic and peridomestic populations can help identify a possible differential risk in the transmission of Chagas disease to humans, mainly in northwestern and east-central Colombia. We characterize the main parameters of feeding behavior and their influence on the longevity and survival of two rat-fed populations of T. dimidiata from Colombia, one in the north-west (from palms in a tropical dry forest area) and the other in the center-east (peridomiciliated), under controlled environmental conditions. The palm population took considerably longer than the peridomestic population to complete its life cycle under experimental laboratory conditions, being both populations univoltine since they have only one life cycle per year. Statistically significant differences were evidenced using Box-Cox model between the survival rates of T. dimidiata populations when the parameters related to blood intake and behavior were incorporated, in contrast to the survival models in which the origin only was considered as a factor. Our results could be used to generate recommendations to guide prevention strategies in communities near sylvatic and peridomiciliated populations of T. dimidiata.

Potential distribution of four vectors of American Cutaneous Leishmaniasis: The effect of El Niño and La Niña episodes from the perspective of the ecological niche.

The potential distribution of four American Cutaneous Leishmaniasis vectors under average conditions during Neutral (in between episodes), El Niño, and La Niña episodes from 2000 to 2018 were constructed through ecological niche modeling. The potential distribution in El Niño and La Niña were compared with the Neutral distribution. The four vector species (Lutzomyia gomezi, Lutzomyia ovallesi, Lutzomyia panamensis, and Lutzomyia trapidoi) decreased the potential distribution with the occurrence of El Niño and La Niña episodes. During El Niño, the reduction was concentrated over the dry ecosystems, while with the occurrence of La Niña, the potential distribution decreased over most of the Neotropic, leaving areas of climatic suitability concentrated in the Andean and Amazon areas, along with some scattered patches. We found evidence that the occurrence of the climatic anomalies has an effect on the potential distribution of this vector species.

Influence of montane altitudinal ranges on species distribution models; evidence in Andean blow flies.

BACKGROUND: Blow flies are a family of dipterans of medical, veterinary and sanitary importance. We aim to predict the current geographical distribution of six neotropical blowfly species with different altitudinal ranges of distribution (high, medium, and lowlands) and degree of synanthropy (eusynanthropic, hemisynanthropic and asynanthropic) based on their existing fundamental niche (EA) in Northwestern South America. METHODS: Geographical records were compiled based on data from museum specimens and literature. The accessible area hypothesis (M) was calculated based on three criteria: (1) Altitudinal range, (2) Synanthropy values deducted based on the Human Influence Index (HII) raster dataset, and (3). The mean dispersal capability of flies. The modeling was performed using the Maxent entropy modeling software. The selection of parameters was made with the R Program ENMeval package. RESULTS: The models were assessed using the area under the operator-partial receiver curve (ROCp). The high statistical performance was evidenced in every modeling prediction. The modeling allowed identifying possible taxonomic inaccuracies and the lack of exhaustive collection in the field, especially for lowlands species. Geographical distribution predicted by the modeling and empirical data was remarkably coherent in montane species. DISCUSSION: The data obtained evidence that montane elevational ranges affect the performance of the distribution models. These models will allow a more precise predicting of medium and high elevation blow flies than lowlands species. Montane species modeling will accurately predict the fly occurrence to use such biological information for medical, legal, veterinary, and conservation purposes.

Geographic abundance patterns explained by niche centrality hypothesis in two Chagas disease vectors in Latin America.

Ecoepidemiological scenarios for Chagas disease transmission are complex, so vector control measures to decrease human-vector contact and prevent infection transmission are difficult to implement in all geographic contexts. This study assessed the geographic abundance patterns of two vector species of Chagas disease: Triatoma maculata (Erichson, 1848) and Rhodnius pallescens (Barber, 1932) in Latin America. We modeled their potential distribution using the maximum entropy algorithm implemented in Maxent and calculated distances to their niche centroid by fitting a minimum-volume ellipsoid. In addition, to determine which method would accurately explain geographic abundance patterns, we compared the correlation between population abundance and the distance to the ecological niche centroid (DNC) and between population abundance and Maxent environmental suitability. The potential distribution estimated for T. maculata showed that environmental suitability covers a large area, from Panama to Northern Brazil. R. pallescens showed a more restricted potential distribution, with environmental suitability covering mostly the coastal zone of Costa Rica and some areas in Nicaragua, Honduras, Belize and the Yucatán Peninsula in Mexico, northern Colombia, Acre, and Rondônia states in Brazil, as well as a small region of the western Brazilian Amazon. We found a negative slope in the relationship between population abundance and the DNC in both species. R. pallecens has a more extensive potential latitudinal range than previously reported, and the distribution model for T. maculata corroborates previous studies. In addition, population abundance increases according to the niche centroid proximity, indicating that population abundance is limited by the set of scenopoetic variables at coarser scales (non-interactive variables) used to determine the ecological niche. These findings might be used by public health agencies in Latin America to implement actions and support programs for disease prevention and vector control, identifying areas in which to expand entomological surveillance and maintain chemical control, in order to decrease human-vector contact.

Effect of El Niño Southern Oscillation cycle on the potential distribution of cutaneous leishmaniasis vector species in Colombia.

Local anomalies in rainfall and temperature induced by El Niño and La Niña episodes could change the structure of the vector community. We aimed to estimate the effect of the El Niño-La Niña cycle in the potential distribution of cutaneous leishmaniasis (CL) vector species in Colombia and to compare the richness of the vectors with the occurrence of CL in the state of Norte de Santander. The potential distributions of four species were modeled using a MaxEnt algorithm for the following episodes: La Niña 2010-2011, Neutral 2012-2015 and El Niño 2015-2016. The relationship between the potential richness of the vectors and the occurrence of CL in Norte de Santander was evaluated with a log-binomial regression model. During the El Niño 2015-2016 episode, Lutzomyia ovallesi and Lutzomyia panamensis increased their distribution into environmentally suitable areas, and three vector species (Lutzomyia gomezi, Lutzomyia ovallesi and Lutzomyia panamensis) showed increases in the range of their altitudinal distribution. During the La Niña 2010-2011 episode, a reduction was observed in the area suitable for occupation by Lutzomyia gomezi and Lutzomyia spinicrassa. During the El Niño 2015-2016 episode, the occurrence of at least one CL case was related to a higher percentage of rural localities showing a richness of vectors = 4. The anomalies in rainfall and temperature induced by the episodes produced changes in the potential distribution of CL vectors in Colombia. In Norte de Santander, during Neutral 2012-2015 and El Niño 2015-2016 episodes, a higher probability of at least one CL case was related to a higher percentage of areas with a greater richness of vectors. The results help clarify the effect of the El Niño-La Niña cycle in the dynamics of CL in Colombia and emphasize the need to monitor climate variability to improve the prediction of new cases.