RESUMEN El cultivo de cebolla de bulbo aparte de ser uno de los principales cultivos de hortalizas a nivel mundial, para Boyacá es considerado uno de los pilares en la economía agrícola regional. Pese a ser tan importante desde el aspecto económico, a nivel agrícola este cultivo posee varios problemas entre los cuales resalta las exigencias nutricionales y las malas prácticas en cuanto al manejo y conservación de los suelos. Es por eso que se hace importante entender cuáles son las variabilidades fisicoquímicas del suelo asociadas al cultivo y estas como pueden estar relacionadas a procesos intrínsecos a escala geográfica local. Para determinar la variabilidad de las condiciones fisicoquímicas del suelo en el cultivo de cebolla de bulbo, se analizaron un total de 15 zonas de 50 × 50 m dentro distrito de riego Usochicamocha. Un total de 15 muestras de suelo y 15 muestras de agua de riego fueron colectadas y posteriormente analizadas en laboratorio. Se obtuvo información de parámetros pH, MO, CE, densidad aparente, textura del suelo, Ca, Mg, K, Na, P, en las muestras de agua, carga de iones, cationes, dureza y turbidez. Los resultados obtenidos permitieron observar una relación significativa entre los atributos del cultivo, propiedades fisicoquímicas del suelo y agua en las diferentes zonas de estudio. Estos resultados apoyan la hipótesis de la existencia de una sinergia entre las propiedades extrínsecas e intrínsecas del cultivo y como tienen una relación entre los atributos de calidad del cultivo de cebolla de bulbo.

ABSTRACT The bulb onion crop is not only one of the main vegetable crops worldwide, but it is also considered one of the pillars of the regional agricultural economy in Boyaca. Despite being so important from the economic point of view, at the agricultural level this crop has several problems among which stand out the nutritional requirements and poor practices in terms of soil management and conservation. That is why it is important to understand what are the physicochemical variabilities of the soil associated with the crop and how these can be related to intrinsic processes at a local geographic scale. To determine the variability of soil physicochemical conditions in the bulb onion crop, a total of 15 zones of 50 × 50 m were analyzed within the Usochicamocha irrigation district. A total of 15 soil samples and 15 irrigation water samples were collected and subsequently analyzed in the laboratory. Information was obtained on pH, MO, EC, bulk density, soil texture, Ca, Mg, K, Na, P, ion load, cations, hardness and turbidity in the water samples. The results obtained allowed observing a significant relationship between crop attributes, physicochemical properties of soil and water in the different study zones. These results support the hypothesis of the existence of a synergy between the extrinsic and intrinsic properties of the crop and how they have a relationship between the quality attributes of the bulb onion crop.

Resumen Neospora caninum es un parásito del filo Apicomplexa que genera grandes pérdidas económicas para la ganadería a nivel mundial. A pesar de su importancia, la información sobre la prevalencia de infección en áreas endémicas de Colombia es escasa. Estudios previos han reportado una alta seroprevalencia en ganado lechero de Boyacá, que sugiere un factor de riesgo significativo para la transmisión activa de la neosporosis. Sin embargo, no hay datos disponibles sobre el estado de infección o la presencia del parásito en la sangre periférica del ganado lechero. En este estudio, se realizó la detección genética de N. caninum por PCR anidada del marcador Nc-5 en muestras de sangre periférica de vacas lecheras de los municipios de Paipa, Toca y Tuta. Se secuenciaron cuatro muestras positivas por el método de Sanger, que se editaron, alinearon y compararon con secuencias disponibles en la base de datos GenBank. Se detectó el ADN del parásito en 23 de las 170 muestras de sangre analizadas. Se estimó un límite cualitativo de detección en las muestras (~64 parásitos por volumen de sangre muestreada). Este es el primer reporte de detección del ADN de N. caninum por PCR en sangre de ganado lechero colombiano. Por lo tanto, futuros trabajos sobre la detección molecular y la genética poblacional de N. caninum en sangre periférica de ganado podrían ser muy útiles para el diagnóstico temprano de la neosporosis y la creación de estrategias más efectivas de vigilancia epidemiológica.

Abstract Neospora caninum is a parasite of the phylum Apicomplexa that causes significant economic losses for cattle husbandry worldwide. Despite its relevance, information regarding infection prevalence in endemic areas of Colombia is scarce. Previous studies have reported a high seroprevalence in dairy cattle from Boyacá, which suggests a significant risk factor for active transmission of neosporosis. However, there is no available data concerning the infection stage or the presence of said parasite in the peripheral blood of dairy cattle. In this study, genetic detection of N. caninum was carried out using a nested PCR with an Nc-5 marker on peripheral blood samples from dairy cows in the municipalities of Paipa, Toca, and Tuta. Four positive samples were sequenced through the Sanger method, which were then edited, aligned, and compared to sequences available in the GenBank database. The parasite’s DNA was detected in 23 out of 170 analyzed blood samples. A qualitative detection limit was estimated (~64 parasites per volume of blood sampled). This is the first report of DNA detection of N. caninum through PCR in blood from Colombian dairy cattle. Thereupon, further studies about N. caninum molecular detection and population genetics in cattle peripheral blood could be very useful for the early diagnosis of neosporosis and creating more effective epidemiological surveillance strategies.

Resumo Neospora caninum é um parasita do filo Apicomplexa que causa perdas econômicas significativas para o gado em todo o mundo. Apesar de sua relevância, as informações sobre a prevalência de infecções na Colômbia em áreas endêmicas são escassas. Estudos anteriores relataram uma alta seroprevalência no gado leiteiro de Boyacá, o que sugere um fator de risco significativo para a transmissão ativa da neosporose bovina. Entretanto, não há dados disponíveis sobre o estágio de infecção ou a presença do referido parasita no sangue periférico do gado leiteiro. Neste estudo, realizou-se a detecção genética de N. caninum por meio uma PCR aninhada com um marcador Nc-5 em amostras de sangue periférico de vacas leiteiras nos municípios de Paipa, Toca e Tuta. Quatro amostras positivas foram sequenciadas através do método Sanger, que foram então editadas, alinhadas e comparadas com as sequências disponíveis no banco de dados do GenBank. O DNA do parasita foi detectado em 23 das 170 amostras de sangue analisadas. Foi estimado um limite de detecção qualitativa (~64 parasitas por volume de sangue amostrado). Este é o primeiro relatório de detecção de DNA de N. caninum através de PCR em sangue de gado leiteiro colombiano. A partir dessas evidências, estudos adicionais sobre a detecção molecular de N. caninum e genética populacional no sangue periférico do gado poderiam ser muito úteis para o diagnóstico precoce da neosporose e para a criação de estratégias de vigilância epidemiológica mais eficazes.

BACKGROUND Panstrongylus rufotuberculatus (Hemiptera-Reduviidae) is a triatomine species with a wide geographic distribution and a broad phenotypic variability. In some countries, this species is found infesting and colonising domiciliary ecotopes representing an epidemiological risk factor as a vector of Trypanosoma cruzi, etiological agent of Chagas disease. In spite of this, little is known about P. rufotuberculatus genetic diversity. METHODS Cytogenetic studies and DNA sequence analyses of one nuclear (ITS-2) and two mitochondrial DNA sequences (cyt b and coI) were carried out in P. rufotuberculatus individuals collected in Bolivia, Colombia, Ecuador and Mexico. Moreover, a geometric morphometrics study was applied to Bolivian, Colombian, Ecuadorian and French Guiana samples. OBJECTIVES To explore the genetic and phenetic diversity of P. rufotuberculatus from different countries, combining chromosomal studies, DNA sequence analyses and geometric morphometric comparisons. FINDINGS We found two chromosomal groups differentiated by the number of X chromosomes and the chromosomal position of the ribosomal DNA clusters. In concordance, two main morphometric profiles were detected, clearly separating the Bolivian sample from the other ones. Phylogenetic DNA analyses showed that both chromosomal groups were closely related to each other and clearly separated from the remaining Panstrongylus species. High nucleotide divergence of cyt b and coI fragments were observed among P. rufotuberculatus samples from Bolivia, Colombia, Ecuador and Mexico (Kimura 2-parameter distances higher than 9%). MAIN CONCLUSIONS Chromosomal and molecular analyses supported that the two chromosomal groups could represent different closely related species. We propose that Bolivian individuals constitute a new Panstrongylus species, being necessary a detailed morphological study for its formal description. The clear morphometric discrimination based on the wing venation pattern suggests such morphological description might be conclusive.

BACKGROUND A previous phylogeographic study revealed two Aedes aegypti African-related mitochondrial lineages distributed in Colombian’s cities with different eco-epidemiologic characteristics with regard to dengue virus (DENV). It has been proposed these lineages might indicate independent invasion sources. OBJECTIVES Assessing to Colombian population structure and to support evidence of its probable source origin. METHODS We analysed a total of 267 individuals from cities of Bello, Riohacha and Villavicencio, which 241 were related to the West and East African mitochondrial lineages (termed here as WAL and EAL, respectively). Eight polymorphic microsatellite loci were analysed aiming population structure. FINDINGS Results indicate substantial gene flow among distant and low-connected cities composing a panmictic population with incipient local differentiation of Ae. aegypti is placed in Colombia. Likewise, genetic evidence indicates no significant differences among individuals related to WAL and EAL is placed. MAIN CONCLUSIONS Minimal genetic differentiation in low-connected Ae. aegypti populations of Colombia, and lack concordance between mitochondrial and nuclear genealogies suggest that Colombian Ae. aegypti shared a common demographic history. Under this scenario, we suggest current Ae. aegypti population structure reflects a single origin instead of contemporary migration, which founding populations have a single source from a mitochondrial polymorphic African ancient.

Resumen Introducción. Aedes aegypti y Ae. albopictus son reconocidos vectores de arbovirus como los del dengue, la fiebre amarilla, el chikungunya y el Zika, en regiones tropicales y subtropicales del mundo. En Colombia, la distribución geográfica de Ae. albopictus ha sufrido un incremento y hoy incluye ciudades como Cali y Medellín. Hasta ahora, sin embargo, no se ha recabado información concluyente sobre su infección viral y su capacidad de transmisión a los humanos. Objetivo. Determinar la infección natural por dengue en ejemplares de Ae. albopictus recolectados en un área urbana de Medellín. Materiales y métodos. Se recolectaron individuos de Ae. albopictus en el campus de la Universidad Nacional de Colombia, sede Medellín. Se confirmó su clasificación taxonómica mediante el análisis del gen citocromo oxidasa I (COI), y se extrajo el ARN total para la identificación del virus del dengue y de los respectivos serotipos. La presencia del genotipo DENV se infirió mediante el análisis del gen NS3. Resultados. El análisis del COI corroboró el estatus taxonómico de Ae. albopictus. Uno de los mosquitos procesados fue positivo para DENV-2 y el análisis del NS3 mostró una gran similitud con el genotipo asiático-americano. Conclusión. Se reporta la infección con DENV-2 en Ae. albopictus en Medellín, Colombia. La presencia del genotipo asiático-americano en una zona urbana sugiere su posible circulación entre humanos y en Ae. albopictus, lo cual alerta sobre su eventual papel en la transmisión del DENV-2, y sobre la necesidad de incluir esta especie en la vigilancia entomológica en Colombia.

Abstract Introduction: Aedes aegypti and Ae. albopictus are recognized vectors of dengue, yellow fever, chikungunya and Zika arboviruses in several countries worldwide. In Colombia, Ae. albopictus geographical distribution has increased to include highly populated cities such as Cali and Medellín. Although this species has been frequently found in urban and semi-urban zones in the country, its role as vector of the dengue fever is poorly known. Objective: To identify the presence of Ae. albopictus specimens naturally infected with dengue virus collected in Medellín. Materials and methods: Insects were collected in the Universidad Nacional de Colombia campus in Medellín. Individuals were classified as Ae. albopictus and confirmed by DNA barcode region analysis. Mosquitoes were processed for dengue virus identification, and a fragment of the NS3 gen was sequenced and compared with DENV-2 genotypes reported in the literature. Results: Sequence analysis of COI indicated Ae. albopictus individuals were similar to those recently reported in Colombia, and genetically close to those from other regions worldwide. Among the pools tested one was positive for DENV-2, and the NS3 analysis indicated it belonged to the Asian-American clade. Conclusion: We report the presence Ae. albopictus naturally infected with the Asian-American genotype of DENV-2 in Colombia. The presence of Ae. albopictus specimens carrying the most common genotype infecting humans in a highly populated city such as Medellín indicates its potential role as dengue vector in Colombia and highlights the relevance of including it in current vector surveillance strategies.

Introducción. Los reportes sobre la diversidad de triatominosy algunos aspectos ecoepidemiológicos en la Isla Margarita se han limitado sólo a dos de los cinco municipios que la conforman. El conocimiento de las especies, su hábitat y la infección, es fundamental para establecer el riesgo en áreas endémicas para la enfermedad de Chagas. Objetivo. Describir la fauna de triatominos, la distribución y la infección por Trypanosoma cruzi en la Isla Margarita, con el fin de aportar conocimientos que permitan establecer y estratificar el riesgo de transmisión de la zona. Materiales y métodos. Se realizó la captura de triatominos en las viviendas y el extradomicilio. En las viviendas se hizo búsqueda activa en el intradomicilio y el peridomicilio, mientras en el extradomicilio, se hizo en palmas y nidos de aves. La infección por T. cruzi se determinó por PCR a partir de las heces. Resultados. Se capturaron 1.154 insectos de cinco especies en los municipios de la isla, Triatoma maculata y Rhodnius pallescens mostraron altos índices de infección en el intra domicilio y en el peridomicilio en Mompós y Talaigua Nuevo. En las palmas, R. pallescens fue hallado infectado en todos los municipios y Eratyrus cuspidatus sólo en San Fernando y Margarita. Conclusión. La presencia de triatominos infectados en las viviendas y en las palmas en los cinco municipios de la isla, llama la atención sobre el potencial riesgo que representan estos insectos en la zona.

Introduction. Information concerning to triatomine diversity and some eco-epidemiologic aspects on Margarita Island has been recorded only from two of the five counties on the island. Knowledge about species habitat and their natural infection is essential to establish the risk for Chagas disease in endemic areas. Objective. The distribution of triatomine insect fauna and its infection with Trypanosoma cruzi was described in order to establish and to stratify the risk of Chagas disease transmission. Material and methods. Each of the 5 counties on Margarita Island were surveyed for triatomid insects inside and outside each dwelling. In the extradomicilary area, searches were conducted in the palms and bird nests located within forests and in pastures near domiciles. Infection with T. cruzi was determined amplifying by PCR the DNA extracted from triatomine feces. Results. Five species of Reduviidae were recovered among the 1,154 triatomines captured in the 5 counties. Triatoma maculata and Rhodnius pallescens showed high infection rates within dwellings and as well as in the peridomestic areas in Mompós and Talaigua Nuevo. On the palm trees, only R. pallescens and Eratyrus cuspidatus were found infected, and only in San Fernando and Margarita. In Cicuco, only R. pallescens was infected. Presence of Triatoma dimidiata was also ascertained.Conclusion. Infected triatomines were present in houses and on palm trees in all counties on the island. These observations indicate a potential risk of Chagas across the entire island; furthermore the presence of T. dimidiata, a very efficient Chagas vector, emphasizes the need to establish its epidemiological status on the island.

Introducción. Triatoma dimidiata es el segundo vector más importante de la enfermedad de Chagas en Colombia, después de Rhodnius prolixus. El conocimiento de la composición genética y la diferenciación de poblaciones es fundamental para el adecuado diseño e implementación de estrategias de control y vigilancia vectorial. Objetivo. Determinar el nivel de variabilidad y diferenciación genética en tres poblaciones colombianas de T. dimidiata provenientes de distintas localidades y hábitats, mediante el análisis molecular de un fragmento del gen mitocondrial ND4. Materiales y métodos. Se analizó el nivel de polimorfismo y la estructura genética de dos poblaciones silvestres de los departamentos de La Guajira (n=10) y Santander (n=10), y de una población intradomiciliaria (n=15) y peridomiciliaria (n=5) del Cesar. Para tal fin, se analizaron las secuencias de nucleótidos de un fragmento del gen mitocondrial ND4. Resultados. T. dimidiata en Colombia demostró tener gran diversidad genética, tanto a nivel de nucleótidos (π: 0,034) como de haplotipo (Hd: 0,863), además de una significativa estructuración de población (fST: 0,761) con un bajo número de migrantes (Nm: 0,157). Las distancias genéticas y las diferencias en los niveles de variabilidad genética entre las tres poblaciones fueron coherentes con una posible subdivisión de población. Conclusión. Este trabajo demostró diferenciación genética entre las poblaciones de T. dimidiata de La Guajira, Cesar y Santander. Se sugiere una posible relación entre tal subdivisión y algunas características eco-epidemiológicas que posee T. dimidiata en el centro-oriente y en el norte de Colombia. Finalmente, este trabajo describe, por primera vez, la utilidad del ND4 como un marcador molecular para el estudio de poblaciones naturales de T. dimidiata.

Introduction. Triatoma dimidiata is the second most important vector of Chagas disease in Colombia after Rhodnius prolixus. Population genetic studies are essential for the adequate design and implementation of vector control and surveillance strategies. Objective. The level of genetic variability and population differentiation was surveyed among three Colombian populations of T. dimidiata from different geographic locations and ecotopes, using ND4 mitochondrial gene. Materials and methods. Genetic comparison was made between two wild populations from La Guajira (n=10) and Santander (n=10) provinces, and one intra (n=15) and one peridomiciliary (n=5) population from the Cesar province. The polymorphism frequencies of the ND4 mitochondrial gene sequence were analyzed to deduce population structure based on the 40 samples. Results. Colombian T. dimidiata showed a high nucleotide (π: 0.034) and haplotype diversity (Hd: 0.863), as well as significant population subdivision (fST: 0.761) and a low migration rate (Nm: 0.157). Genetic distances and variability differences among populations indicate distinct population subdivision amongst the three provinces. Conclusion. ND4 proved useful in elucidating the significant genetic differentiation that has occurred among T. dimidiata populations from La Guajira, Cesar and Santander. The analysis suggested a relationship between population subdivision and some eco-epidemiological attributes of this vector from the central eastern and northwestern regions of Colombia.

Rhodnius pallescens is the main vector of Trypanosoma cruzi in Panama and one of the most relevant secondary vectors in Colombia. Despite the importance of this species, there is limited knowledge about the genetic variability along its geographical distribution. In order to evaluate the degree of karyotype variability we analyzed the meiotic behavior and banding pattern of the chromosomes of 112 males of R. pallescens coming from different regions of Colombia and Panama. Using the C-banding technique we identified two chromosomal patterns or cytotypes characterized by differences in the amount, size and distribution of constitutive heterochromatic regions in the chromosome complement (2n = 20 autosomes plus XY in males). The individuals can be easily classified in each cytotype by the analysis of the chromosomes during first meiotic prophase. The frequencies of the cytotypes are variable according to the geographic origin of the populations. This chromosomal divergence together with morphological data supports the existence of three genetically different populations of R. pallescens and provides new information to understand the distribution dynamics of this species.