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Psathyromyia (Psathyromyia) shannoni sensu stricto (Dyar) is a vector of Leishmania parasite and the second sandfly of medical importance with a wide geographical but discontinuous distribution in America. Preliminary genetic structure analysis using a mitochondrial marker shows that the species integrated by at least four lineages could be the result of ecological adaptations to different environmental scenarios, but this hypothesis had never been proven. The aim of the present study was to analyse whether the genetic structure that detected Pa. shannoni ss. is associated with divergence or conservatism niche. Using Ecological Niche Models (ENMs) theory, we estimated the potential distribution for each genetic lineage, and then, we evaluated the equivalency niche for assessing whether climatic niche was more different than expected. The ENMs identify different suitable distribution areas but the same climatic or ecological conditions for the genetic lineages of Pa. shannoni (conservatism niche). Our findings allow us to speculate that other potential processes or events could be related to the genetic differentiation of Pa. shannoni. These studies are important because they allow us to identify the factors that could restrict the potential distribution of the different lineages whose vectorial competence is still unknown.
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Leishmania , Psychodidae , Animales , Psychodidae/genética , Psychodidae/parasitología , Ecosistema , Modelos Teóricos , Geografía , FilogeniaRESUMEN
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.
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Leishmania , Leishmaniasis , Psychodidae , Animales , Psychodidae/fisiología , Leishmania/fisiología , Leishmaniasis/veterinaria , América del Sur , EcosistemaRESUMEN
Dipetalogaster maxima is a primary vector of Chagas disease in the Cape region of Baja California Sur, Mexico. The geographic distribution of D. maxima is limited to this small region of the Baja California Peninsula in Mexico. Our study aimed to construct the ecological niche models (ENMs) of this understudied vector species and the parasite responsible for Chagas disease (Trypanosoma cruzi). We modelled the ecological niches of both species under current and future climate change projections in 2050 using four Representative Concentration Pathways (RCPs): RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5. We also assessed the human population at risk of exposure to D. maxima bites, the hypothesis of ecological niche equivalency and similarity between D. maxima and T. cruzi, and finally the abundance centroid hypothesis. The ENM predicted a higher overlap between both species in the Western and Southern coastal regions of the Baja California Peninsula. The climate change scenarios predicted a Northern shift in the ecological niche of both species. Our findings suggested that the highly tourist destination of Los Cabos is a high-risk zone for Chagas disease circulation. Overall, the study provides valuable data to vector surveillance and control programs.
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Enfermedad de Chagas , Parásitos , Triatominae , Trypanosoma cruzi , Humanos , Animales , México/epidemiología , Cambio Climático , Insectos Vectores/parasitología , Enfermedad de Chagas/veterinaria , Triatominae/parasitologíaRESUMEN
OBJECTIVE: To determine the species distribution, abundance, and diversity of culicids in the Yucatan Peninsula (YP); their potential distribution, using ecological niche modeling (ENM), and the risk of contact with urban and rural populations. MATERIALS AND METHODS: A cross-sectional study was carried out through the YP. The diversity of species was determined with the Shannon index. The potential distribution of the culicids was determined through the ENM, as well as the risk of urban and rural populations through contact with vectors. RESULTS: A total of 10 699 specimens, 15 genera and 52 species were registered. Campeche and the Biosphere Reserve of Calakmul exhibited the highest diversity. CONCLUSIONS: The ENM predict a high suitability in all the YP of Ae. aegypti, An. albimanus, An. pseudopuntipennis, Cx. coronator, and Cx. quinquefasciatus. The vector species that exhibited the highest risk of contact in the YP were Cx. quinquefasciatus, Ae. aegypti and Ae. albopictus.
OBJETIVO: Determinar la distribución, abundancia y diversidad de los culícidos de la Península de Yucatán (PY), su distribución potencial utilizando modelos de nicho ecológico (MNE) y el riesgo de contacto con poblaciones urbanas y rurales. MATERIAL Y MÉTODOS: Se realizó un estudio transversal. La diversidad fue determinada por el índice de Shannon. La distribución potencial de los culícidos se determinó a través de MNE, así como el riesgo de las poblaciones urbanas y rurales al contacto con los vectores. RESULTADOS: En total, se registraron 10 699 especímenes, 15 géneros y 52 especies. Campeche y la Reserva de la Biosfera de Calakmul presentaron la mayor diversidad. CONCLUSIONES: El MNE predice una alta idoneidad en toda la PY para Ae. aegypti, An. albimanus, An. pseudopuntipennis, Cx. coronador y Cx. quinquefasciatus. Las especies de vectores que presentaron el mayor riesgo de contacto en la PY fueron Cx. quinquefasciatus, Ae. aegypti y Ae. albopictus.
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Biodiversidad , Culicidae , Mosquitos Vectores , Aedes , Animales , Anopheles , Estudios Transversales , Culex , Insectos Vectores , México , Densidad de PoblaciónRESUMEN
OBJECTIVE: To determine the abundance and geographic distribution of the main malaria vectors, which are influenced by habitat characteristics and ecological factors that directly impact adult density and the dynamics of malaria transmission in Mexico. MATERIALS AND METHODS: Samples of larvae were collected from 19 states in Mexico. Each larval habitat was characterized in situ determining the following parameters: water depth, turbidity, percentage of vegetation cover, amount of detritus, presence of algae, light intensity, type of vegetation, amount of predators, habitat stability, altitude, and hydrologic type. RESULTS: A total of 21 687 larvae corresponding to 13 anopheline species were obtained from 149 aquatic habitats. The most abundant species were Anopheles pseudopunctipennis (52.91%), An. albimanus (39.14%) and An. franciscanus (5.29%). The multiple logistic regression analysis showed a negative association between An. pseudopunctipennis and water turbidity (ß=-1.342; Wald=6.122; p=0.013) and the amount of detritus (ß=-2.206; Wald=3.642; p=0.050). While in An. albimanus, there was a significant positive association with water turbidity (ß=1.344; Wald=4.256; p=0.039), a negative correlation was found with the altitude (ß=-3.445; Wald=5.407; p =0.020). The highest mosquito species diversity index was found in Chiapas (Fisher's α=1.20) and the lowest diversity in Chihuahua (Fisher's α=0.26). The greatest richness was found in streams (n=11). CONCLUSIONS: The two most abundant species were: An. albimanus and An. pseudopunctipennis. Detailed knowledge of the distribution and characteristics of their larval habitats will be useful for the effective implementation of control strategies in Mexico.
OBJETIVO: Determinar la abundancia y la distribución geográfica de los principales vectores de la malaria, las cuales están influenciadas por las características del hábitat y los factores ecológicos que afectan directamente la densidad de los adultos y la dinámica de la transmisión de la malaria en México. MATERIAL Y MÉTODOS: Se obtuvieron muestras de larvas de 19 estados de México. Cada hábitat larvario se caracterizó in situ determinando los siguientes parámetros: profundidad del agua, turbidez, porcentaje de cobertura vegetal, cantidad de detritus, presencia de algas, intensidad de luz, tipo de vegetación, cantidad de depredadores, estabilidad del hábitat, altitud y tipo hidrológico. RESULTADOS: Se identificaron un total de 21 687 larvas pertenecientes a 13 especies de anofelinos, de 149 hábitats acuáticos. Las tres especies más abundantes fueron Anopheles pseudopunctipennis (52.91%), An. albimanus (39.14%) y An. franciscanus (5.29%). El análisis de regresión logística múltiple mostró una asociación negativa para An. pseudopunctipennis y la turbidez del agua (ß=-1.342; Wald= 6.122; p=0.013) y la cantidad de detritus (ß=-2.206; Wald= 3.642; p=0.050). Para An. albimanus se encontró una asociación positiva significativa con la turbidez del agua (ß=1.344; Wald= 4.256; p=0.039) y una correlación negativa con la altitud (ß=-3.445; Wald=5.407; p=0.020). El índice de diversidad más alto se encontró en Chiapas (α de Fisher=1.20) y la diversidad más baja en Chihuahua (α de Fisher=0.26). La mayor riqueza se encontró en los arroyos (n=11). CONCLUSIONES: Las dos especies más abundantes fueron An. albimanus y An. pseudopunctipennis. El conocimiento detallado de la distribución y características de sus hábitats larvales será útil para la implementación efectiva de las estrategias de control en México.
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Anopheles , Ecosistema , Mosquitos Vectores , Animales , Larva , Malaria/transmisión , México , Densidad de Población , Análisis de Regresión , Especificidad de la Especie , Agua/parasitologíaRESUMEN
The leishmaniasis is a complex disease system, caused by the protozoan parasite Leishmania and transmitted to humans by the vector Lutzomyia spp. Since it is listed as a neglected disease according to the World Health Organization, the aim of this study was to determine the current and future niche of cutaneous and visceral leishmaniasis in the Neotropical region. We built the ecological niche model (ENM) of cutaneous (N= 2 910 occurrences) and visceral (N= 851 occurrences) leishmaniasis using MaxEnt algorithm. Nine bioclimatic variables (BIO1, BIO4, BIO5, BIO6, BIO7, BIO12, BIO13, BIO14, BIO15 (downloaded from the Worldclim) and disease occurrences data were used for the construction of ENM for three periods (current, 2050 and 2070) and four climate change scenarios (RCP 2.6, 4.5, 6.0 y 8.5). We analyzed the number of pixels occupied, identity niche, modified niche (stable, loss, and gain) and seasonality. Our analyses indicated the expansion for cutaneous leishmaniasis (CL), a comparison for visceral leishmaniasis (VL). We rejected the null hypothesis of niche identity between CL and VL with Hellinger's index = 0.91 (0.92-0.98) and Schoener's Index = 0.67 (0.85-1.00) but with an overlap niche of 56.3 %. The differences between the two leishmaniasis types were detected in relation to RCP scenarios and niche shifts (area gained / loss). Seasonality was more important for CL. We provided a current picture of CL and VL distributions and the predicted distributional changes associated to different climate change scenarios for the Neotropical region. We can anticipate that increasing range is likely although it will depend locally on the future trends in weather seasonality.
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Ecosistema , Leishmaniasis Cutánea/epidemiología , Leishmaniasis Visceral/epidemiología , Clima Tropical , Animales , Cambio Climático , Humanos , Insectos Vectores , América Latina/epidemiología , Leishmaniasis Cutánea/transmisión , Leishmaniasis Visceral/transmisión , Modelos Biológicos , Psychodidae , Factores de Riesgo , Estaciones del Año , TemperaturaRESUMEN
BACKGROUND: Anopheles darlingi is considered the most efficient malaria vector in the Neotropical region. In Mexico, its role as an incriminated vector of Plasmodium has not been confirmed in the Lacandon forest. Similarly, knowledge about bionomic and larval ecology is scarce. The study aim was to identify and describe the larval habitats of An. darlingi in Chiapas, México. METHODS: Standard larval collections were performed in the Lacandon forest region and in the Soconusco region of southern Chiapas from January 2010 to April 2014, including dry and rainy seasons. Mean larval density of An. darlingi was estimated according to hydrological types, and associations between the presence of An. darlingi and environmental factors including ecological parameters and geographic positions were statistically analysed. RESULTS: One hundred and twelve aquatic habitats were analysed, 80 from the Lacandon forest region and 32 from the Soconusco region; 94.64% of these sites presented anopheline larvae. In total, 10,977 larvae belonging to 11 Anopheles species were collected. The 19 (out of 112) larval habitats positive to An. darlingi were: rain puddles (26.32%), ground pools (21.05%), ponds (15.79%), ditches (15.79%), river margins (10.53%) and streams (10.53%). Overall, the average (±SD) larval density was 6.60 ± 2.41 larvae per dip. Multiple logistic regression analysis showed that temporary habitats, green algae presence and stagnant water were associated with An. darlingi larval presence. The positive habitats were found in the Lacandon forest region during the rainy season (May-September). No specimens were found in the Soconusco region of the coastal plain of Chiapas. CONCLUSION: The mosquito An. darlingi larval habitats were found in different hydrological types. The habitat stability, presence of algae and water current were the main factors for An. darlingi larval occurrence. The information on the characteristics of the larval habitats of An. darlingi will be useful in sustainable programmes for malaria control in the Lacandon forest region, Chiapas.
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Anopheles/crecimiento & desarrollo , Ecosistema , Insectos Vectores , Animales , Larva/crecimiento & desarrollo , México , Densidad de Población , Estaciones del AñoRESUMEN
Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs) were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.
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Insectos Vectores/clasificación , Triatominae/clasificación , Animales , Enfermedad de Chagas/transmisión , Ecosistema , Geografía Médica , México , Modelos Biológicos , Densidad de PoblaciónRESUMEN
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.
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Studies of morphological and genetic variation in vector populations across environmental gradients can help researchers to estimate species' responses to climate change scenarios and the potential risk of disease-causing pathogen expansion, which impacts negatively on human health. In this study, we analysed the effect of altitudinal gradients on the phenotypic response of the hard tick of medical and veterinary importance, Rhipicephalus sanguineus sensu lato (s.l.). Specimens of R. sanguineus s.l. were collected from host animals in one of Mexico's regions with high climatic heterogeneity (Veracruz), and geometric morphometric theory was employed to assess the response of three morphological characters to the altitudinal gradient. Additionally, genetic similarity data were provided, and ecological niche models were used to project the climatic distribution in the region. Our results demonstrate that the shape and size of ticks respond to altitude. Molecular identification indicate that all analysed samples correspond to the tropical lineage recently named Rhipicephalus linnaei. According to ecological niche models, the mean annual temperature contributes significantly to the spatial distribution of this tick species, with areas of higher suitability in the mountainous region. These changes in morphological structure and the presence of ticks at higher altitudinal gradients suggest that R. linnaei has a high potential for adaptation. Due to the variability of ecosystems in the state of Veracruz, our results could be valuable in assessing the response of this tick in a changing environment, aiding in predicting future scenarios in the distribution and abundance of this species.
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Enfermedades de los Perros , Rhipicephalus sanguineus , Rhipicephalus , Animales , Humanos , Perros , Rhipicephalus/genética , México , Ecosistema , Rhipicephalus sanguineus/genética , Altitud , FilogeniaRESUMEN
Bats are one of the groups of mammals with the highest number of associated Trypanosoma taxa. There are 50 Trypanosoma species and genotypes infecting more than 75 species of bats across five continents. However, in Mexico, the inventory of species of the genus Trypanosoma associated with bats is limited to only two species (Trypanosoma vespertilionis and Trypanosoma cruzi) even though 140 species of bats inhabit this country. Specifically, 91 bat species have been recorded in the state of Veracruz, but records of trypanosomatids associated with this mammalian group are absent. Due to the complex Trypanosoma-bat relationship, the high diversity of bat species in Veracruz, as well as the lack of records of trypanosomatids associated with bats for this state, the aim of this work was to analyze the diversity of species of the genus Trypanosoma and their presence from a bat community in the central area of the state of Veracruz, Mexico. During the period of January to August 2022 in the Tequecholapa Environmental Management Unit where bats were collected using mist nets and blood samples were obtained from their thumbs. We extracted genetic material and amplified a fragment of 800 bp of the 18S ribosomal gene of the genus Trypanosoma by conventional PCR. The positive amplicons were sequenced, and phylogenetic reconstruction was performed to identify the parasite species. A total of 285 bats (149â, 136â) belonging to 13 species from 10 genera and a single family (Phyllostomidae) were collected. Twenty-three specimens from six species tested positive for the presence of Trypanosoma dionisii, Trypanosoma sp. Neobat 4, and a potential novelty species provisionally named as Trypanosoma sp. Neobat 6. The results of the present work increase the number of species of the genus Trypanosoma infecting bats in Mexico and in the Neotropical region.
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Quirópteros , Trypanosoma cruzi , Trypanosoma , Animales , Quirópteros/parasitología , Filogenia , México , Trypanosoma/genética , Trypanosoma cruzi/genética , Secuencia de BasesRESUMEN
In America, the presence of Rhipicephalus sanguineus sensu stricto and Rhipicephalus linnaei has been confirmed. Both species are found in sympatry in the southern United States, northern Mexico, southern Brazil, and Argentina. The objective of this work is to evaluate the projection of the potential distribution of the ecological niche of Rhipicephalus sanguineus sensu lato in two climate change scenarios in Mexico and the border with Central America and the United States. Initially, a database of personal collections of the authors, GBIF, Institute of Epidemiological Diagnosis and Reference, and scientific articles was built. The ENMs were projected for the current period and two future scenarios: RCP and SSP used for the kuenm R package, the ecological niche of R. sanguineus s.l. It is distributed throughout the Mexico and Texas (United States), along with the border areas between Central America, Mexico, and the United States. Finally, it is observed that the ecological niche of R. sanguineus s.l. in the current period coincides in three degrees with the routes of human migration. Based on this information, and mainly on the flow of migrants from Central America to the United States, the risk of a greater gene flow in this area increases, so the risk relating to this border is a latent point that must be analyzed.
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Vespa mandarinia Smith is a species with native distribution in Asia and with the potential distribution of invasion in the Americas. We use ecological niche models to be able to predict their potential distribution in Asia and their projection in the Americas using KUENM in R in climate change scenarios. The ecological niche of V. mandarinia is potentially distributed in Asia and is expected with invasion potential in the east coast of USA, part of the México, Central America, and South America, while for 2050 it is projected with dispersion in North and Central of USA and rest of the Americas. The realized niche expanded in the Americas. Ecological niche modeling helps us infer the distribution of this species in Asia and its possible establishment of invasion in the USA, México, Central America, and South America.
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Cambio Climático , Avispas , Distribución Animal , Animales , América Central , Ecosistema , Modelos Teóricos , América del Norte , América del SurRESUMEN
Tick-borne rickettsioses represent a severe public health problem that has increased in recent decades by several activities that place human populations in contact with a wide range of vectors. In particular, Rickettsia parkeri, an eschar-associated spotted fever agent, represents an emerging pathogen that has been gradually identified throughout America. In the present work, we compiled an occurrence database of these bacteria, as well as its vectors, in order to identify the potential distribution of these bacteria and to detect the risk areas where this emerging pathogen may be circulating. The results show the at-risk areas to be broad regions in Central America, on the coast of Venezuela, Colombia, Ecuador, Peru, and Chile, part of Brazil and Argentina, and the greater part of Bolivia, Paraguay, and Uruguay. Particularly, in Mexico, conditions exist for widespread dissemination. Our results must be considered for the establishment of active acarological surveillance in previously unsampled areas, as well as the establishment of prevention measures for vulnerable populations and risk groups participating in outdoor activities that can place them in contact with this pathogen.
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The Asian tiger mosquito Aedes albopictus is currently the most invasive vector species, with a widespread global distribution. Aedes albopictus is the potential vector of diverse arboviruses, including Zika and dengue. This study updated the ecological niche model of Ae. albopictus and inferred the potential distribution of natural Wolbachia infections in Ae. albopictus in México. The ecological niche models were constructed based on diverse model settings to better estimate the potential distributions and uncertainty indices of both Ae. albopictus and its natural Wolbachia infections in México. The distribution of Ae. albopictus covered the states across Northern México, the Gulf of México, the Pacific Coast of México, Central México, and the southeast of México. The ecological niche model of the natural Wolbachia infections in Ae. albopictus populations anticipated the occurrence of natural Wolbachia infections in the southeast of México, the Chiapas border with Guatemala, and Veracruz. These results can be used to prioritize vector surveillance and control programs in México for strategic and future decision-making; however, it is still necessary to establish active surveillance programs to assess model predictions based on the independent sampling of Ae. albopictus from different invasion zones in México. Finally, vector surveillance should also screen the natural Wolbachia infections in Ae. albopictus to validate Wolbachia predictions across México, particularly in the southeast of México.
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Amblyomma mixtum is a Neotropical generalist tick of medical and veterinary importance which is widely distributed from United States of America to Ecuador. The aim of this study was to evaluate changes in the geographic projections of the ecological niche models of A. mixtum in climate change scenarios in America. We constructed a database of published scientific publications, personal collections, personal communications, and online databases. Ecological niche modelling was performed with 15 Bioclimatic variables using kuenm in R and was projected to three time periods (Last Glacial Maximum, Current and 2050) for America. Our model indicated a wide distribution for A. mixtum, with higher probability of occurrence along the Gulf of Mexico and occurring in a lesser proportion in the Pacific states, Central America, and the northern part of South America. The areas of new invasion are located mainly on the border of Mexico with Guatemala and Belize, some regions of Central America and Colombia. We conclude that the ecological niche modelling are effective tools to infer the potential distribution of A. mixtum in America, in addition to helping to propose future measures of epidemiological control and surveillance in the new potential areas of invasion.
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Amblyomma/fisiología , Distribución Animal , Cambio Climático , Ecosistema , Animales , América Central , Modelos Biológicos , América del Norte , América del SurRESUMEN
Aedes aegypti control programs require more sensitive tools in order to survey domestic and peridomestic larval habitats for dengue and other arbovirus prevention areas. As a consequence of the COVID-19 pandemic, field technicians have faced a new occupational hazard during their work activities in dengue surveillance and control. Safer strategies to monitor larval populations, in addition to minimum householder contact, are undoubtedly urgently needed. Drones can be part of the solution in urban and rural areas that are dengue-endemic. Throughout this study, the proportion of larvae breeding sites found in the roofs and backyards of houses were assessed using drone images. Concurrently, the traditional ground field technician's surveillance was utilized to sample the same house groups. The results were analyzed in order to compare the effectiveness of both field surveillance approaches. Aerial images of 216 houses from El Vergel village in Tapachula, Chiapas, Mexico, at a height of 30 m, were obtained using a drone. Each household was sampled indoors and outdoors by vector control personnel targeting all the containers that potentially served as Aedes aegypti breeding sites. The main results were that the drone could find 1 container per 2.8 found by ground surveillance; however, containers that were inaccessible by technicians in roofs and backyards, such as plastic buckets and tubs, disposable plastic containers and flowerpots were more often detected by drones than traditional ground surveillance. This new technological approach would undoubtedly improve the surveillance of Aedes aegypti in household environments, and better vector control activities would therefore be achieved in dengue-endemic countries.
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Lutzomyia longipalpis is a complex of species which has a wide but discontinuous distribution from southeastern Mexico to northern Argentina and Uruguay. To date, eight mitochondrial haplogroups have been identified along its distribution although key environmental tolerances and ecological niche models have been analyzed only at the complex level. The aim of the present study was to analyze whether genetic diversification using three mitochondrial genes of the Lu. longipalpis complex is associated with niche divergence and to explore evolution of distributional projections of all haplogroups between the Last Glacial Maximum (LGM; 21,000 yrs ago) and the present. Current occurrence of all haplogroups was used to develop ecological niche models (ENM) and these were projected in both periods to quantify and identify geographic area shifts. Environmental space was used to estimate niche similarity between major clades and pairwise between individual haplogroups. The two major Lu. longipalpis clades (Mex, CA, Col and Ven vs Arg and Bra) had significantly different environmental space, indicating niche divergence. Environmental space overlap of southern haplogroups was variable, with divergent niche, except between Arg and ArgBra. The most suitable regions for the ArgBra haplogroup were northeastern and southeastern Brazil, and the Gran Chaco region. In contrast, ENM of haplogroups within the northern major clade have significantly similar niche, with highest geographic ENM suitability along both the Caribbean and Pacific coasts. The intensity and coverage of high suitability areas in the LGM decreased for most haplogroups in the present. Integrating ENM and phylogenetic analyses has allowed us to test hypotheses of niche similarity between Lu. longipalpis haplogroups and major clades, and to identify conserved distributional areas of haplogroups since the LGM, with the exception of Arg. Evidence for distributional shifts and overlap of haplogroups is important to analyze Leishmaniasis´ eco-epidemiology and to successfully monitor and control transmission.
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Ecosistema , Haplotipos , Insectos Vectores/clasificación , Insectos Vectores/genética , Mitocondrias , Filogeografía , Psychodidae/clasificación , Psychodidae/genética , Animales , Argentina , Brasil , Región del Caribe , América Central , Colombia , México , UruguayRESUMEN
The majority of the Yucatán State, México, presents subtropical climate that is suitable for many species of mosquitoes that are known to be vectors of diseases, including those from the genera Aedes and Culex. The objective of this study is to identify the geographic distribution of five species from these two genera and estimate the human population at risk of coming in contact with them. We compiled distributional data for Aedes aegypti (L.), Aedes (Howardina) cozumelensis (Diaz Najera), Culex coronator Dyar and Knab, Culex quinquefasciatus Say, and Culex thriambus Dyar from several entomological studies in Yucatán between March 2010 and September 2014. Based on these data, we constructed ecological niche models to predict the spatial distribution of each species using the MaxEnt algorithm. Our models identified areas with suitable environments for Ae. aegypti in most of Yucatán. A similar percentage of urban (97.1%) and rural (96.5%) populations were contained in areas of highest suitability for Ae. aegypti, and no spatial pattern was found (Moran's I = 0.33, P = 0.38); however, we found an association of abundance of immature forms of this species with annual mean temperature (r = 0.19, P ≤ 0.001) and annual precipitation (r = 0.21, P ≤ 0.001). Aedes cozumelensis is also distributed in most areas of the Yucatán State; Cx. quinquefasciatus, Cx. coronator, and Cx. thriambus are restricted to the northwest. The information generated in this study can inform decision-making to address control measures in priority areas with presence of these vectors.
Asunto(s)
Aedes/fisiología , Distribución Animal , Culex/fisiología , Mosquitos Vectores/fisiología , Aedes/crecimiento & desarrollo , Animales , Culex/crecimiento & desarrollo , Sistemas de Información Geográfica , Larva/fisiología , México , Modelos BiológicosRESUMEN
This study explores the present day distribution of Lutzomyia longipalpis in relation to climate, and transfers the knowledge gained to likely future climatic conditions to predict changes in the species' potential distribution. We used ecological niche models calibrated based on occurrences of the species complex from across its known geographic range. Anticipated distributional changes varied by region, from stability to expansion or decline. Overall, models indicated no significant north-south expansion beyond present boundaries. However, some areas suitable both at present and in the future (e.g., Pacific coast of Ecuador and Peru) may offer opportunities for distributional expansion. Our models anticipated potential range expansion in southern Brazil and Argentina, but were variably successful in anticipating specific cases. The most significant climate-related change anticipated in the species' range was with regard to range continuity in the Amazon Basin, which is likely to increase in coming decades. Rather than making detailed forecasts of actual locations where Lu. longipalpis will appear in coming years, our models make interesting and potentially important predictions of broader-scale distributional tendencies that can inform heath policy and mitigation efforts.