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The ecology of vector-borne diseases (VBDs) is an important system of great complexity, which involves the knowledge about the pathogens and animal species entailed in maintaining transmission cycles in a given locality, including those that act as vectors and reservoirs for the transmitted pathogens. To understand the ecology of some VBDs, we studied vectors, reservoirs, and pathogens of different VBDs, including dengue, leishmaniasis, Chagas disease, malaria, Zika, and chikungunya in the municipality of La Mesa, Cundinamarca, Colombia, a locality close to the capital, Bogotá. Vectors and mammals were sampled in urban and rural areas between May and August 2019. Molecular analyses were performed for the detection of pathogens in mammals and vectors, and of blood-meal sources in insects. Several vectors and mammals collected in this study have been involved in pathogen transmission cycles or may have a potential role in them. The findings of this study suggest that in the municipality of La Mesa, there are both vector and potential reservoir species, which are or could be implicated in the maintenance of the cycles of vector-borne diseases such as leishmaniasis and Chagas disease. Although arbovirus infections, such as dengue, are reported in the municipality, arbovirus presence was not detected. These findings highlight the importance of ongoing surveillance of vectors and associated control operations in La Mesa, of relevance to other locations where vectors and animal hosts also occur.

Studies on the feeding behavior of hematophagous insects, particularly those of medical importance, are relevant for tracking possible pathogen transmission routes and identifying biases in the choice of vertebrates. We evaluated host selection of blood-feeding mosquitoes in a disturbed forest in the Magdalena Medio valley in Colombia from March 2017 to April 2018, after the introduction of Zika virus to the Americas from the 2015–2016 outbreak. We estimated vertebrate diversity and collected blood-engorged female mosquitoes. Genomic DNA/RNA was extracted from the mosquito’s abdomen for vertebrate host identification and pathogen detection. We performed conventional PCR and sequencing, using universal primers targeting vertebrate regions of the eukaryotic mitochondrial genome to determine bloodmeal host. Additionally, we tested for the presence of flaviviruses in all mosquito samples with RT-PCR. Based on the identity and quantity of detected bloodmeals, we performed mosquito-vertebrate interaction network analysis and estimated topology metrics. In total, we collected 292 engorged female mosquitoes representing 20 different species. Bloodmeal analyses identified 26 vertebrate species, the majority of which were mammals (N = 16; 61.5%). No flaviviruses of medical importance were detected from the samples. Although feeding patterns varied, network analyses showed a high degree of specialization by mosquitoes and revealed ecological and phylogenetic relationships among the host community. We conclude that host selection or preference by mosquitoes is species specific.

Studies on the feeding behavior of hematophagous insects, particularly those of medical importance, are relevant for tracking possible pathogen transmission routes and identifying biases in the choice of vertebrates. We evaluated host selection of blood-feeding mosquitoes in a disturbed forest in the Magdalena Medio valley in Colombia from March 2017 to April 2018, after the introduction of Zika virus to the Americas from the 2015-2016 outbreak. We estimated vertebrate diversity and collected blood-engorged female mosquitoes. Mosquito genomic DNA/RNA was extracted for vertebrate host identification and pathogen detection. We performed conventional PCR and sequencing, using universal primers targeting vertebrate regions of the eukaryotic mitochondrial genome to determine bloodmeal host. Additionally, we tested for the presence of flaviviruses in all mosquito samples with RT-PCR. Based on the identity and quantity of detected bloodmeals, we performed mosquito-vertebrate interaction network analysis and estimated topology metrics. In total, we collected 292 engorged female mosquitoes representing 20 different species. Bloodmeal analyses identified 26 vertebrate species, the majority of which were mammals (N=16; 61.5%). No flavivirus infection was confirmed. Although feeding patterns varied, network analyses showed a high degree of specialization by mosquitoes and revealed ecological and phylogenetic relationships among the host community. We conclude that host selection or preference by mosquitoes is species specific.

A description is presented of Lutzomyia tolimensis sp. nov., a new species of the subgenus Helcocyrtomyia, series sanguinaria. It was collected in dwellings, peridomestic environment and in nearby forest patches located in the foothills of the Andean Central Cordillera, where in 2004-2006 occurred the largest epidemic ever recorded of leishmaniasis in Colombia. The male of this species is differentiated from other members of the series sanguinaria based on the following combination of characters: (i) base of coxite with 0-3 subequal setae, (ii) spines of gonostyle organized in positions 2.1.2, (iii) spines inserted on distal half of gonostyle and (iv) relationship of alar indices. The female is recognized principally by the following characters: (i) palpomere V longer than III, (ii) length of labro-epipharynx and (iii) relationship of the alar indices.

Phlebotomine vector ecology was studied in the largest recorded outbreak of American cutaneous leishmaniasis in Colombia in 2004. In two rural townships that had experienced contrasting patterns of case incidence, this study evaluated phlebotomine species composition, seasonal abundance, nocturnal activity, blood source, prevalence of Leishmania infection, and species identification. CDC miniature light traps were used to trap the phlebotomines. Traps were set indoors, peridomestically, and in woodlands. Natural infection was determined in pools by polymerase chain reaction-Southern blot, and blood sources and species identification were determined by sequencing. Large differences were observed in population abundance between the two townships evaluated. Lutzomyia longiflocosa was the most abundant species (83.1%). Abundance was higher during months with lower precipitation. Nocturnal activity was associated with human domestic activity. Blood sources identified were mainly human (85%). A high prevalence of infection was found in L. longiflocosa indoors (2.7%) and the peridomestic setting (2.5%). L. longiflocosa was responsible for domestic transmission in Chaparral.

Durante más de tres décadas el uso de insecticidas químicos ha sido la principal medida de control para la fiebre de dengue en el departamento del Atlántico, Colombia. Se evaluó el estado de la susceptibilidad a insecticidas de uso en salud pública de tipo organoclorado, organofosforado, piretroide y carbamato en poblaciones de A. aegypti del departamento del Atlántico. Se realizaron ensayos biológicos aplicando la metodología estandarizada por el Centro de Control y Prevención de Enfermedades (CDC), con dosis diagnóstica para deltametrina (6,25 µg/ml), lambdacialotrina (6,25 µg/ml), malatión (100 µg/ml), fenitrotión (75 µg/ml), propoxur (12,5 µg/ml) y dicloro-difenil-tricloretano DDT (150 µg/ml) en mosquitos de A. aegypti (F2) de los municipios de Barranquilla, Soledad (Villa Katanga y Floresta), Malambo, Puerto Colombia y Baranoa. Todas las poblaciones mostraron susceptibilidad al malatión y deltametrina, cinco a fenitrotión, cuatro a propoxur y dos a lambdacialotrina. En todas se evidenció pérdida de susceptibilidad al diclorodifenil-tricloretano. No se encontraron diferencias significativas en los porcentajes de mortalidad entre las poblaciones para malatión (p = 0,15), DDT (p = 0,54) y deltametrina (p = 0,99); mientras que para lambdacialotrina (p << 0,01), propoxur (p < 0,01) y fenitotrión (p << 0,01) se encontraron diferencias significativas. La aplicación de insecticidas químicos para el control de la fiebre de dengue en el departamento del Atlántico ha generado pérdida de la susceptibilidad en las poblaciones del mosquito vector.

La fiebre de dengue es endémica para el departamento del Atlántico; en 2007 se presentaron 3,104 casos. Para la prevención y control de esta enfermedad se ha usado el larvicida temefos. Sin embargo, se desconoce si la presión a la que han sido sometidas las poblaciones de Aedes aegypti con este insecticida ha generado resistencia. Se evaluó la susceptibilidad a temefos en larvas de A. aegypti en siete municipios y un corregimiento del departamento del Atlántico, entre el 2007 y el 2008. Se realizaron bioensayos utilizando la concentración diagnóstica para temefos (0,012 ppm) en larvas de tercer y cuarto estadio temprano de A. aegypti (F2) aplicando la metodología recomendada por la Organización Mundial de la Salud (OMS). Se realizaron dos repeticiones, cada una con cuatro réplicas y un control. En dos localidades se registró susceptibilidad al temefos (mortalidad de 100%), en cuatro se requiere verificación para vigilancia (mortalidades entre 86% 93%) y en dos se presentó resistencia (mortalidad de 34% y 45%). Se encontraron diferencias significativas en los porcentajes de mortalidad entre las poblaciones (Kruskal-Wallis, P < 0.05). Es necesario monitorear las poblaciones de este vector en el departamento del Atlántico con el fin de generar la línea base de susceptibilidad que permita implementar estrategias preventivas y métodos alternativos de control pertinentes a cada localidad para disminuir la presión de selección a la que están sometidas las larvas por la aplicación de este larvicida.

A new species of Culicoides of the subgenus Diphaomyia Vargas from high altitudes of the Andes in Colombia is described and photographied. The species is compared with its similar congener Culicoides marinkellei Wirth & Lee. Data on the collecting site and notes on the species daily activity are also provided., Facultad de Ciencias Naturales y Museo