Assessing pyrethroid resistance in Aedes aegypti from Cordoba Colombia: Implications of kdr mutations.

Resistance to insecticides is one of the great challenges that vector control programs must face. The constant use of pyrethroid-type insecticides worldwide has caused selection pressure in populations of the Aedes aegypti vector, which has promoted the emergence of resistant populations. The resistance mechanism to pyrethroid insecticides most studied to date is target-site mutations that desensitize the voltage-gated sodium channel (VGSC) of the insect to the action of pyrethroids. In the present study, susceptibility to the pyrethroid insecticides permethrin, lambda-cyhalothrin, and deltamethrin was evaluated in fourteen populations from the department of Córdoba, Colombia. The CDC bottle bioassay and WHO tube methods were used. Additionally, the frequencies of the F1534C, V1016I, and V410L mutations were determined, and the association of resistance with the tri-locus haplotypes was examined. The results varied between the two techniques used, with resistance to permethrin observed in thirteen of the fourteen populations, resistance to lambda-cyhalothrin in two populations, and susceptibility to deltamethrin in all the populations under study with the CDC method. In contrast, the WHO method showed resistance to the three insecticides evaluated in all populations. The frequencies of the mutated alleles ranged from 0.05-0.43 for 1016I, 0.94-1.0 for 1534C, and 0.01-0.59 for 410L. The triple homozygous mutant CIL haplotype was associated with resistance to all three pyrethroids evaluated with the WHO bioassay, while with the CDC bioassay, it was only associated with resistance to permethrin. This study highlights the importance of implementing systematic monitoring of kdr mutations, allowing resistance management strategies to be dynamically adjusted to achieve effective control of Aedes aegypti.

First report of Aedes albopictus (Diptera: Culicidae) in the North of Colombia.

Aedes albopictus is considered a potential vector of arboviruses in Colombia. Females and males naturally infected with dengue, Zika and chikungunya viruses have already been found in this country. We document the first record of Ae. albopictus in the Cordoba department, in North of Colombia. The finding was carried out during Ae. aegypti collection activities in the Ayapel, Montelibano, Planeta Rica, Pueblo Nuevo and Puerto Libertador municipalities. The entomological material was collected in water containers such as cement water tanks, tanks, bottles, tires, abandoned toilets, and plastic lids with natural water located in the intradomicile, peridomicile, and extra-domicile spaces of the homes. We collected 658 Ae. albopictus samples in the larva and pupa stages, and once these reached adulthood, we determined that 389 were female and 269 were male. This is the first record of the presence of Ae. albopictus in the Cordoba department.

First report of Aedes albopictus (Diptera: Culicidae) in the North of Colombia

ABSTRACT Aedes albopictus is considered a potential vector of arboviruses in Colombia. Females and males naturally infected with dengue, Zika and chikungunya viruses have already been found in this country. We document the first record of Ae. albopictus in the Cordoba department, in North of Colombia. The finding was carried out during Ae. aegypti collection activities in the Ayapel, Montelibano, Planeta Rica, Pueblo Nuevo and Puerto Libertador municipalities. The entomological material was collected in water containers such as cement water tanks, tanks, bottles, tires, abandoned toilets, and plastic lids with natural water located in the intradomicile, peridomicile, and extra-domicile spaces of the homes. We collected 658 Ae. albopictus samples in the larva and pupa stages, and once these reached adulthood, we determined that 389 were female and 269 were male. This is the first record of the presence of Ae. albopictus in the Cordoba department.

Phylogenetic analysis of Dengue-2 serotypes circulating in mangroves in Northern Cordoba, Colombia.

INTRODUCTION: In this study, we aimed to identify DENV-2 subtypes in Aedes aegypti pools collected between 2011 and 2017 in a rural area of Northern Cordoba, Colombia ("La Balsa"). METHODS: RT-PCR was performed to analyze the capsid/pre-membrane region (C-PrM). Sequencing and phylogenetic bayesian inference using reference DENV-2 sequences were performed. RESULTS: Twelve pools that tested positive for DENV-2 were characterized based on the C-PrM region and grouped under the Asian/American clade. CONCLUSIONS: This study is the first to report the DENV-2 Asian-American subtype in a rural area of Cordoba region, which is associated with severe dengue and local epidemics.

Phylogenetic analysis of Dengue-2 serotypes circulating in mangroves in Northern Cordoba, Colombia

Abstract INTRODUCTION: In this study, we aimed to identify DENV-2 subtypes in Aedes aegypti pools collected between 2011 and 2017 in a rural area of Northern Cordoba, Colombia ("La Balsa"). METHODS: RT-PCR was performed to analyze the capsid/pre-membrane region (C-PrM). Sequencing and phylogenetic bayesian inference using reference DENV-2 sequences were performed. RESULTS: Twelve pools that tested positive for DENV-2 were characterized based on the C-PrM region and grouped under the Asian/American clade. CONCLUSIONS: This study is the first to report the DENV-2 Asian-American subtype in a rural area of Cordoba region, which is associated with severe dengue and local epidemics.

Diversidad genética y estructura poblacional de Anopheles triannulatus s.l. en Córdoba, Colombia, determinadas mediante el método de región de código de barras de ADN / Genetic diversity and population structure of Anopheles triannulatus s. l. in the department of Córdoba, Colombia, using DNA barcoding

Introducción. A pesar de los recientes reportes de infección con Plasmodium spp. en poblaciones relacionadas con los linajes noroeste y sureste, Anopheles triannulatus no está incriminado como vector de la transmisión de malaria en Colombia. La diversidad genética puede delimitar la información sobre el flujo génico y la diferenciación poblacional entre localidades con malaria. Objetivo. Estimar la diversidad genética de An. triannulatus en cinco municipios con alta y baja incidencia de malaria en el departamento de Córdoba. Materiales y métodos. La recolección entomológica se hizo entre agosto y noviembre de 2016 en los municipios de Tierralta, Puerto Libertador, Montelíbano, Sahagún y Planeta Rica. Como marcador genético, se utilizó la región de código de barras de ADN del gen mitocondrial COI. El análisis genético incluyó la estimación de los parámetros de diversidad haplotípica, estructura genética y flujo génico, la prueba D de neutralidad de Tajima, la red de haplotipos y las relaciones filogenéticas. Resultados. Se obtuvieron 148 secuencias parciales de 655 nucleótidos del gen COI, de los cuales se derivaron 44 haplotipos. Los haplotipos H2 y H21 fueron los más frecuentes en las poblaciones. Los valores de la prueba D de Tajima fueron negativos y no significativos (p>0,10). Los estimadores de estructura genética (FST=0,01427) y de flujo génico (Nm=17,27) evidenciaron que no hubo diferenciación genética en las poblaciones muestreadas debido al importante intercambio de migrantes. Mediante las inferencias filogenéticas y la red de haplotipos, se identificó una sola especie sin diferenciación geográfica o de linajes en el rango geográfico estudiado. Conclusión. La diversidad genética calculada para An. triannulatus en este contexto, indicó que las poblaciones están en un intercambio constante.

Introduction: Anopheles triannulatus is not incriminated as a vector of malaria transmission in Colombia despite recent reports of infection with Plasmodium spp. in populations related to the northwestern and southeastern lineages. Genetic diversity can delimit information about gene flow and population differentiation in localities with malaria. Objective: To estimate the genetic diversity of An. triannulatus in five municipalities with high and low incidence of malaria in the department of Córdoba. Materials and methods: The entomological collections were done between August and November, 2016, in Tierralta, Puerto Libertador, Montelíbano, Sahagún, and Planeta Rica. We used the COI barcoding fragment as molecular marker. The genetic analysis included the estimation of genetic parameters such as the diversity haplotype, the genetic structure, the gene flow, the Tajima's D test, the haplotype network, and the phylogenetic relationship. Results: We obtained 148 sequences with a length of 655 nucleotides of the COI gene, from which we derived 44 haplotypes. The H2 and H21 haplotypes were the most frequent in the populations. The values of the Tajima's D test were negative and not significant (p>0.10). The genetic structure index (FST=0.01427) and the gene flow (Nm=17.27) evidenced no differentiation between sampled populations due to the high exchange of migrants. Using phylogenetic inferences and the haplotype network, we identified one single species without geographic differentiation or lineages in the geographic range studied. Conclusions: The genetic diversity calculated for An. triannulatus in this context indicated stable populations in constant exchange.