Susceptibility to insecticides and resistance mechanisms in Aedes aegypti from the Colombian Caribbean Region.

We determined the susceptibility to insecticides and the biochemical and molecular mechanisms involved in resistance in nine populations of Aedes aegypti (L.) of the Colombian Caribbean region. Bioassays were performed on larvae for susceptibility to temephos and on adults to the insecticides malathion, fenitrothion, pirimiphos-methyl, permethrin, deltamethrin, λ-cyhalothrin and cyfluthrin. The resistance ratio (RR) for each insecticide in the populations was determined, using the susceptible Rockefeller strain as a susceptible control. Additionally, we evaluated the response of the populations to the diagnostic dose (DD) of the organochlorine pesticide DDT. The following biochemical mechanisms associated with resistance were studied: α-esterases, ß-esterases, mixed-function oxidases (MFO), glutathione s-transferases (GST) and insensitive acetylcholinesterase (iAChE) as well as the presence of kdr I1,016 mutation and its frequency. All populations studied showed susceptibility to the organophosphates evaluated (RR < 5-fold), except for the Puerto Colombia and Soledad populations which showed high resistance (RR 15-fold) and moderate resistance (RR 5-fold) to temephos, respectively, and Sincelejo (Sucre) with moderate resistance to pirimiphos-methyl (RR 5-fold). All populations evaluated with DD of DDT were found to be resistant with 2-28% of mortality. Variability was observed in the resistance to pyrethroids: permethrin (RR 1.2- to 30.8-fold), deltamethrin RR 0.9- to 37.8-fold), λ-cyalothrin (RR 3.4- to 83-fold) and cyfluthrin (RR 0.3- to 33.8-fold). Incipiently α-esterases and MFO levels were found in the Valledupar population; MFO showed the same profile in Cienaga and GST in the Sincelejo population, all other populations showed unaltered profiles of the enzymes evaluated. The kdr I1,016 mutation was found in all populations evaluated with variability in its allelic and genotypic frequencies.

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.

Evaluation of susceptibility to organophosphates in populations of Aedes aegypti in La Guajira, Colombia / Evaluación de la sensibilidad a organofosforados en poblaciones de Aedes aegypti (L.) (Diptera: Culicidae) del departamento de La Guajira, Colombia

Introduction. Dengue is a public health problem in La Guajira region. Control has focused on the vector using insecticides, including organophosphates. Objective. To evaluate the state of susceptibility to organophosphates insecticides in fifteen Aedes aegypti (L.) populations in La Guajira, Colombia. Materials and methods. We collected samples of third-instar larvae and adult mosquitoes of Ae. aegypti in the municipalities of Albania, Barrancas, Dibulla, Distracción, El Molino, Fonseca, Hatonuevo, La Jagua del Pilar, Maicao, Manaure, Riohacha, San Juan del Cesar, Uribia, Urumita, Villanueva. Bioassays for temefos, malathion, and pirimiphos-methyl were carried out following the methodology of the World Health Organization, and the bottle technique using the guidance of the Centers for Disease Control and Prevention. Susceptibility to temefos was determined through the resistance ratio between lethal concentration 50 and lethal concentration 95; for the compounds temefos, malathion and pirimiphos-methyl, susceptibility was calculated using diagnostic dose and diagnostic time in the populations evaluated. Rockefeller susceptible strain was used as a control. Results: All evaluated populations of Ae. aegypti from La Guajira were found to be susceptible to temefos (ratio resistance to CL50<5.0; ratio resistance to CL95<5.0; 98 - 100 % mortality); pirimiphosmethyl (99 - 100 % mortality), and malathion (100 % mortality). Conclusion. Based on the results, the use of temefos, malathion, and pirimiphosmethyl is feasible for the control of Ae. aegypti in the evaluated populations.

Introducción. El dengue es un problema de salud pública para el departamento de La Guajira. El control se ha enfocado en el vector con el uso de insecticidas, entre ellos los organofosforados. Objetivo. Evaluar el estado de la sensibilidad a insecticidas organofosforados de quince poblaciones de Aedes aegypti (L.) en el departamento de La Guajira, Colombia. Materiales y métodos. Se realizaron bioensayos para temefos, malatión y metil-pirimifos en larvas de tercer estadio y mosquitos adultos de Ae. aegypti en los municipios de Albania, Barrancas, Dibulla, Distracción, El Molino, Fonseca, Hatonuevo, La Jagua del Pilar, Maicao, Manaure, Riohacha, San Juan del Cesar, Uribia, Urumita y Villanueva, siguiendo la metodología de la Organización Mundial de la Salud (OMS) y la técnica de botellas usando la guía de los de los Centers for Disease Control and Prevention, respectivamente. Se determinó la sensibilidad por medio de la razón de resistencia a CL50 y CL95 (RRCL50, RRCL95) para temefos y a dosis y tiempo diagnóstico para temefos, malatión y metilpirimifos en las poblaciones de campo evaluadas, usando como control la cepa sensible Rockefeller. Resultados. Las 15 poblaciones del departamento de La Guajira son sensibles a: temefos (razón de la resistencia a RRCL50<5,0; relación de resistencia a CL95<5,0; 98 a 100 % de mortalidad); metil-pirimifos (99 a 100 % de mortalidad) y malatión (100 % de mortalidad). Conclusión. Con base en los resultados obtenidos, es factible el uso de temefos, malatión y metil-pirimifos para el control de Ae. aegypti en las poblaciones evaluadas.

Vector competence of lambda-cyhalothrin resistant Aedes aegypti strains for dengue-2, Zika and chikungunya viruses in Colombia.

Aedes aegypti is the primary vector of dengue, Zika, and chikungunya viruses. Studies have shown that insecticide resistance affects vector competence (VC) of some mosquito species. This study evaluates the effect of resistance to lambda-cyhalothrin and kdr V1016I mutation genotypes on the VC of Ae. aegypti strains for DENV-2, ZIKV, and CHIKV. Three Ae. aegypti strains with gradual lambda-cyhalothrin resistance (susceptible, resistant, and highly resistant) were infected with DENV-2, ZIKV, and CHIKV. Individual mosquitoes were tested to detect virus infection in the abdomen and head-salivary glands, using RT-PCR, and genotypes for V1016I mutations using allele-specific PCR. Recorded VC variables were midgut infection rate (MIR), dissemination rate (DIR), and dissemination efficiency (DIE). Lambda-cyhalothrin resistance affects differentially VC variables for ZIKV, DENV-2, and CHIKV. For ZIKV, an apparent gradual increase in DIR and DIE with the increase in insecticide resistance was observed. For DENV-2 the MIR and DIE were higher in insecticide resistant strains. For CHIKV, only MIR could be evaluated, this variable was higher in insecticide resistance strains. The presence of kdr V1016I mutation on mosquito resistant strains did not affect VC variables for three study viruses.

Susceptibility to Organophosphates in Culex quinquefasciatus from Colombia.

Susceptibility to organophosphates was evaluated in 2 populations of Culex quinquefasciatus from the department of Atlantico, Colombia. Bioassays for temephos, malathion, and pirimiphos-methyl were performed with 3rd-stage larvae and adult females of Cx. quinquefasciatus from the municipalities of Soledad and Puerto Colombia, following the methods of the World Health Organization and Centers for Disease Control and Prevention, respectively. The median lethal concentration (LC50) and 90% lethal concentration (LC90) resistance ratios (RRLC50 and RRLC90) were determined for each insecticide in the field populations evaluated, using the Cartagena strain as the susceptible control. Relative to LC50 and LC90 of the Cartagena strain, the population from Puerto Colombia was moderately resistant to temephos (RRLC50 5.7-fold) and malathion (RRLC50 8.6-fold, RRLC90 9-fold) and susceptible to pirimiphos-methyl (RRLC50 and RRLC90 < 5-fold). The population from Soledad was susceptible to temephos and pirimiphos-methyl (RRLC50 and RRLC90 < 5-fold) and showed moderate resistance to malathion (RRLC50 7.5-fold). It is important to emphasize that routine monitoring of insecticide resistance in Cx. quinquefasciatus helps us detect resistance early and improve the effectiveness of control strategies.

Spatial Distribution of Pyrethroid Resistance and kdr Mutations in Aedes aegypti from La Guajira, Colombia.

Dengue, chikungunya, and Zika are of great concern to the public health of Colombia. One of the main control strategies for these diseases is the application of insecticides directed at the Aedes aegypti vector. However, insecticide resistance has been increasingly recorded in the country, making control measures difficult. Here, we evaluated the resistance profiles for pyrethroids in populations of Ae. aegypti from La Guajira, Colombia. The frequency (diagnostic dose, DD) and intensity (2×, 5×, and 10× DD) of resistance to permethrin, deltamethrin, and lambda-cyhalothrin were determined in 15 populations of Ae. aegypti from La Guajira, Colombia, using the bottle bioassay. The kdr mutations V1016I, F1534C, and V410L, were identified, and their allele and genotype frequencies were calculated. Finally, the mortality values for the analyzed pyrethroids were interpolated following the IDW method for predicting pyrethroid resistance. The populations of Ae. aegypti showed a high frequency of resistance to permethrin with a low to moderate intensity, which was associated with the triple-resistant haplotype LL410/II1016/CC1534. They remain susceptible to deltamethrin and, in some populations, expressed the risk of developing resistance to lambda-cyhalothrin.

[Characterization of multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions in Barranquilla (Colombia)]. / Caracterización de bacilos gramnegativos multi-resistentes, aislados en pacientes hospitalizados en instituciones de salud de Barranquilla (Colombia).

BACKGROUND: The emergence of carbapenem resistant gramnegative bacilli has become a problem of public health worldwide, because it is associated with high mortality rates, increased levels of resistance to other antimicrobials, increased potential for dissemination transition and increase in health care costs. AIM: To characterize multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions of Barranquilla (Colombia). METHODS: A descriptive study was conducted on the phenotypic and genotypic characterization of bacterial resistance in infections associated with health care, mediated by carbapenemases in bacterial isolates sent by laboratories belonging to the laboratory network of the Department of Atlántico. RESULTS: KPC was the most frequent carbapenemase in Enterobacterales (27.6%), predominantly in Klebsiella pneumoniae (13.1%) alone and associated with other carbapenemases. In Pseudomonas aeruginosa, VIM carbapenemase (32.8%) predominated and OXA in Acinetobacter baumannii (17.1%). CONCLUSION: A wide distribution of multi-resistant strains producing carbapenemases in Atlantic health institutions was found, which expressed the following resistance mechanisms: KPC, VIM, NDM, OXA.

Behavioral Aspects of Phlebotomine Sand Flies Associated with a Case of Cutaneous Leishmaniasis in Atlántico, Northern Colombia.

After the first autochthonous case of cutaneous leishmaniasis was reported in the Atlántico department in the Caribbean region of Colombia, entomological sampling was conducted in the specific areas where the infection might have occurred. CDC traps were installed inside and outside dwellings in the peri-urban and rural areas of a settlement in the municipality of Luruaco. Sampling was performed during the night with protected human bait, and phlebotomine sand flies were actively sampled from potential diurnal resting sites within dwellings. Ten species of the genus Lutzomyia were identified; Lutzomyia evansi was the dominant species (78%) in the rural and peri-urban areas as well as in the different sampled habitats, followed by Lutzomyia panamensis and Lutzomyia gomezi. There was a 100% household infestation by Lu. evansi, and its indoor mean abundance was 13.3 sand flies/CDC trap/night. The indoor mean abundance of Lu. panamensis and Lu. gomezi was only 0.9 and 0.8 sand flies/CDC trap/night, respectively. Female Lu. evansi were collected with protected human bait, mostly in the peridomestic area, with sustained activity during the night and a slight increase in the activity from 19:00 to 23:00 hours. Of the total sand flies captured in the diurnal resting sites, 73.1% were collected from the walls of bedrooms and corresponded to Lu. evansi, Lutzomyia cayennensis cayennensis, and Lutzomyia trinidadensis. Owing to their vectorial importance, the species on which entomological surveillance should be focused are Lu. evansi, Lu. panamensis, and Lu. gomezi. The biting and resting behavior reported in this study will help guide vector prevention and the control of leishmaniasis within the study area.

Mechanisms associated with pyrethroid resistance in populations of Aedes aegypti (Diptera: Culicidae) from the Caribbean coast of Colombia.

Aedes aegypti is the main vector of dengue, chikungunya, and Zika viruses, which are of great public health importance in Colombia. Aedes control strategies in Colombia rely heavily on the use of organophosphate and pyrethroid insecticides, providing constant selection pressure and the emergence of resistant populations. In recent years, insecticide use has increased due to the increased incidence of dengue and recent introductions of chikungunya and Zika. In the present study, pyrethroid resistance was studied across six populations of Ae. aegypti from the Caribbean coast of Colombia. Susceptibility to λ-cyhalothrin, deltamethrin, and permethrin was assessed, and resistance intensity was determined. Activity levels of enzymes associated with resistance were measured, and the frequencies of three kdr alleles (V1016I, F1534C, V410L) were calculated. Results showed variations in pyrethroid susceptibility across Ae. aegypti populations and altered enzyme activity levels were detected. The kdr alleles were detected in all populations, with high variations in frequencies: V1016I (frequency ranging from 0.15-0.70), F1534C (range 0.94-1.00), and V410L (range 0.05-0.72). In assays of phenotyped individuals, associations were observed between the presence of V1016I, F1534C, and V410L alleles and resistance to the evaluated pyrethroids, as well as between the VI1016/CC1534/VL410 tri-locus genotype and λ-cyhalothrin and permethrin resistance. The results of the present study contribute to the knowledge of the mechanisms underlying the resistance to key pyrethroids used to control Ae. aegypti along the Caribbean coast of Colombia.

Susceptibility to Pyrethroids and the First Report of L1014F kdr Mutation in Culex quinquefasciatus (Diptera: Culicidae) in Colombia.

The use of insecticides for the control of Aedes aegypti (L.) (Diptera: Culicidae) in Colombia has indirectly influenced the susceptibility status of Culex quinquefasciatus Say populations. We evaluated pyrethroid susceptibility in two populations of Cx. quinquefasciatus in the Atlantico Department of Colombia and its possible resistance mechanism (kdr mutation). Bottle bioassays were performed for permethrin, deltamethrin, and λ-cyhalothrin in female mosquitoes of Cx. quinquefasciatus. The resistance ratios (RRs) for KC50 and LC50 for each insecticide in the field populations examined were determined, using the Cartagena strain as the susceptible control. The L1014F kdr mutation was identified in the para gene of the voltage-gated sodium channel (vgsc), along with its allelic and genotypic frequency. Low knockdown resistance (RRKC50) to deltamethrin was found in Puerto Colombia and Soledad populations as well as low resistance to λ-cyalothrin in this latter population. Moderate knockdown resistance to permethrin was found in both populations. At 24 h post-exposure on the other hand, there was low resistance (RRLC50) to permethrin in Puerto Colombia and moderate resistance in Soledad. Moderate resistance to deltamethrin was found in Puerto Colombia and low resistance in Soledad. Low resistance to λ-cyhalothrin was seen in Puerto Colombia and moderate resistance in Soledad. Variability was found in the susceptibility to the pyrethroids in the populations of Cx. quinquefasciatus evaluated, and the L1014F kdr mutation is reported for the first time as a possible pyrethroid resistance mechanism in this species in Colombia.

Dynamics of Population Immunity Due to the Herd Effect in the COVID-19 Pandemic.

The novel Coronavirus 2 Severe Acute Respiratory Syndrome (SARS-Cov-2) has led to the Coronavirus Disease 2019 (COVID-19) pandemic, which has surprised health authorities around the world, quickly producing a global health crisis. Different actions to cope with this situation are being developed, including confinement, different treatments to improve symptoms, and the creation of the first vaccines. In epidemiology, herd immunity is presented as an area that could also solve this new global threat. In this review, we present the basis of herd immunology, the dynamics of infection transmission that induces specific immunity, and how the application of immunoepidemiology and herd immunology could be used to control the actual COVID-19 pandemic, along with a discussion of its effectiveness, limitations, and applications.

[Epidemiological behavior of hepatitis A in Barranquilla, Colombia, in the period 2013-2017]. / Comportamiento epidemiológico de la hepatitis A en Barranquilla-Colombia, durante los años 2013 a 2017.

OBJECTIVE: To analyze the epidemiological behavior of hepatitis A in the district of Barranquilla (Colombia), in the period 2013-2017. MATERIALS AND METHODS: Descriptive study, in which the database of all hepatitis A cases reported in the district of Barranquilla during the observation period were retrospectively reviewed. RESULTS: There were 293 new cases of hepatitis A reported in the district of Barranquilla, of which 62.4% occurred in men and 37.6% in women. The age groups most affected by the disease were adults (39.6%), followed by young people and schoolchildren (15%, respectively). The incidence of hepatitis A in the district of Barranquilla decreased between 2013 and 2016 from 10.9 to 1.5 cases per 100 000 inhabitants; however, in 2017 there was a slight increase to 2.5 cases per 100 000 inhabitants. CONCLUSIONS: Hepatitis A is an event of interest for public health in the district of Barranquilla, and the behavior of its incidence has had a downward trend in recent years.

OBJETIVO: Analizar el comportamiento epidemiológico de la hepatitis A en el Distrito de Barranquilla (Colombia), durante los años 2013 a 2017. METODOLOGÍA: Estudio descriptivo, en el que se revisó de forma retrospectiva la base de datos de todos los casos de hepatitis A notificados en el Distrito de Barranquilla durante el periodo de observación. RESULTADOS: Se notificaron 293 casos nuevos de hepatitis A en el Distrito de Barran-quilla, de los cuales el 62,4% eran hombres y el 37,6% restantes mujeres. Los grupos etarios más afectados fueron los adultos con el 39,6% de los casos, seguido de jóvenes y niños en etapa escolar con el 15% respectivamente. En cuanto a la incidencia de hepatitis A en el Distrito de Barranquilla se observó un descenso entre los años 2013 a 2016 al pasar de 10,9 a 1,5 casos por 100 000 habitantes; sin embargo, en el 2017 se observó un leve aumento en la incidencia a 2,5 por 100 000 habitantes. CONCLUSIONES: La Hepatitis A es un evento de interés en salud pública para el Distrito de Barranquilla, que ha mantenido un comportamiento a la baja de su incidencia en los últimos años.

Co-occurrence of V1016I and F1534C mutations in the voltage-gated sodium channel and resistance to pyrethroids in Aedes aegypti (L.) from the Colombian Caribbean region.

BACKGROUND: Knockdown resistance is conferred primarily by non-synonymous mutations that reduce pyrethroids binding to voltage-gated sodium channels. In 2014, kdr mutation V1016I in Aedes aegypti populations resistant to pyrethroids was reported for the first time in Colombiα, in 2016 another kdr mutation, F1534C, and in 2018 the mutation V419L. Nine populations of A. aegypti, previously characterized as being resistant to λ-cyhalothrin, deltamethrin, cyfluthrin and permethrin, were used for this study. Genomic DNA was used to determine genotypes by allele-specific PCR for mutations V1016I and F1534C, and to determine their association with pyrethroid resistance. RESULTS: All the populations analyzed showed both mutations, with allelic frequencies of 0.07-0.35 for I1016 and 0.47-0.88 for C1534. A percentage of co-occurrence of mutant homozygotes I1016/C1534 of 5.3% was detected. A significant positive correlation was found between the frequency of the genotype I1016 and the resistance to permethrin, λ-cyhalothrin and cyfluthrin, but not to deltamethrin; on the other hand, the correlation was not significant for the C1534 genotype and the four pyrethroids evaluated. No significant correlation was found between the frequencies of the mutations V1016I and F1534C. CONCLUSIONS: Both mutations V1016I and F1534C are present in A. aegypti populations of the Colombian Caribbean, and although the frequency of F1534C exceeds V1016I, the latter was correlated to resistance to pyrethroid insecticides. © 2018 Society of Chemical Industry.

Seroreactivity and prevalence of syphilis in donors at a blood bank in Barranquilla, Colombia / Serorreacción y prevalencia de sífilis en donantes de un banco de sangre de Barranquilla, Colombia

Introduction: Syphilis is a public health concern given its high impact on morbidity and mortality. Objective: We aimed to determine the association of syphilis seroreactivity and seroprevalence with sociodemographic variables of donors at a blood bank in the district of Barranquilla, Colombia, during 2015 and 2016. Materials and methods: We conducted a descriptive cross-sectional study based on the results of the treponemal and nontreponemal tests and the sociodemographic variables of the study population. We performed a univariate analysis to determine the absolute and relative frequencies for each categorical variable. We determined the seroreactivity against Treponema pallidum and the prevalence of active syphilis infection, and we used Pearson's chi-square test to evaluate the differences between the proportions. Results: We found a seroreactivity of 1.86% in individuals with previous T. pallidum infection, and a prevalence of 0.93% in those with active T. pallidum infection. These values were higher in adult men and older adults, widowers, the unemployed, and people living in municipalities of the Department of Atlántico other than Barranquilla and its metropolitan area. The incidence of syphilis infection showed a significant association with sex and occupation. Conclusion: In comparison to the national average, syphilis seroreactivity was high among blood donors. There was an association between syphilis infection incidence and sociodemographic variables such as sex and occupation.

Introducción. La sífilis es una enfermedad de interés en salud pública por sus elevadas tasas de morbilidad y mortalidad. Objetivo. Determinar la serorreacción y la seroprevalencia de sífilis según las variables sociodemográficas de los donantes de un banco de sangre del distrito de Barranquilla, Colombia, durante 2015 y 2016. Materiales y métodos. Se hizo un estudio descriptivo de corte transversal basado en los resultados de las pruebas treponémicas y no treponémicas. Se analizaron las variables sociodemográficas de la población estudiada y se hizo un análisis univariado en el que se determinaron las frecuencias absoluta y relativa de cada una de las variables categóricas. Se determinó la serorreacción a Treponema pallidum y la prevalencia de la infección activa. Se utilizó la prueba de ji al cuadrado de Pearson para evaluar las diferencias entre las proporciones. Resultados. Se encontró una serorreacción de 1,86 % para la infección previa con T. pallidum y una prevalencia de 0,93 % para la infección activa, las cuales fueron más altas en hombres adultos y en adultos mayores, viudos, desempleados y personas residentes en otros municipios del departamento de Atlántico diferentes de Barranquilla y su área metropolitana. Se encontró una asociación significativa entre la sífilis y las variables de sexo y ocupación. Conclusión. Se registró una serorreacción elevada a T. pallidum en donantes de sangre, comparada con el promedio nacional. Se encontró asociación entre la sífilis, y las variables sociodemográficas de sexo y ocupación, principalmente.

[Presence of Haemagogus equinus Theobald, 1903 (Diptera: Culicidae), in Soledad and Malambo, in the Province of Atlántico, Colombia]. / Presencia de Haemagogus equinus Theobald, 1903 (Diptera: Culicidae) en los municipios de Soledad y Malambo en el departamento del Atlántico, Colombia, 1998--2005.

INTRODUCTION: Yellow fever is a serious illness public health importance and is transmitted by mosquitoes of the genera Haemagogus and Sabethes in the rural and forest environments, and by Aedes aegypti in the urban setting. In Colombia, Haemagogus janthinomys and H. equinus are considered efficient vectors of this viral disease. OBJECTIVE: The presence of the mosquito Haemagogus equinus was recorded over an 8 year period, in the periurban areas of the Soledad and Malambo municipalities (Atlantico Province) of northern Colombia. MATERIALS AND METHODS: The data was obtained from records of the entomological collections from two collection sites: (1) 14 larva traps located at the Erneasto Cortissoz airport in the municipality of Soledad between 1997--2005 and (2) 10 larva traps located at Vergara and Velasco Batallion in the municipality of Malambo in 2005. RESULTS: Haemogogus equinus was reported for the first time in Soledad in 1998. In the following 8 years, 197 larvae were reported. The individuals were found sharing the trap with Aedes aegypti, Culex nigripalpus and Uranotaenia lowii. In Malambo, the first discovery of H.equinus occurred in 2005, with a total of 641 larvae. No other Culicidae were associated with it. CONCLUSION: The presence of H. equinus in larvitraps located near the urban zone, shows adaptation to the use of artificial containers as larval habitats, Urbanization of this species in zones with a high Ae. aegypti infestation index increases the potential introduction of sylvan yellow fever virus and constitutes a risk for re-emergence of urban cycles of yellow fever.

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.

Evaluación de la sensibilidad a organofosforados en poblaciones de Aedes aegypti (L. ) (Diptera: Culicidae) del departamento de La Guajira, Colombia / Evaluation of susceptibility to organophosphates in populations of Aedes aegypti (L. ) (Diptera: Culicidae) in La Guajira, Colombia

Introducción. El dengue es un problema de salud pública para el departamento de La Guajira. El control se ha enfocado en el vector con el uso de insecticidas, entre ellos los organofosforados. Objetivo. Evaluar el estado de la sensibilidad a insecticidas organofosforados de quince poblaciones de Aedes aegypti (L.) en el departamento de La Guajira, Colombia. Materiales y métodos. Se realizaron bioensayos para temefos, malatión y pirimifos- metil en larvas de tercer estadio y mosquitos adultos de Ae. aegypti en los municipios de Albania, Barrancas, Dibulla, Distracción, El Molino, Fonseca, Hatonuevo, La Jagua del Pilar, Maicao, Manaure, Riohacha, San Juan del Cesar, Uribia, Urumita y Villanueva, siguiendo la metodología de la Organización Mundial de la Salud (OMS) y la técnica de botellas usando la guía de los de los Centers for Disease Control and Prevention, respectivamente. Se determinó la sensibilidad por medio de la relación de resistencia a CL50 y CL95 (RRCL50, RRCL95) para temefos y a dosis y tiempo diagnóstico para temefos, malatión y pirimifos-metil en las poblaciones de campo evaluadas, usando como control la cepa sensible Rockefeller. Resultados. Las 15 poblaciones del departamento de La Guajira son sensibles a: temefos (relación de la resistencia a CL50<5,0; relación de resistencia a CL95<5,0; 98 a 100 % de mortalidad); pirimifos-metil (99 a 100 % de mortalidad) y malatión (100 % de mortalidad). Conclusión. Con base en los resultados obtenidos, es factible el uso de temefos, malatión y pirimifos-metil para el control de Ae. aegypti en las poblaciones evaluadas.

Introduction. Dengue is a public health problem in La Guajira region. Control has focused on the vector using insecticides, including organophosphates. Objective. To evaluate the state of susceptibility to organophosphates insecticides in fifteen Aedes aegypti (L.) populations in La Guajira, Colombia. Materials and methods. We collected samples of third-instar larvae and adult mosquitoes of Ae. aegypti in the municipalities of Albania, Barrancas, Dibulla, Distracción, El Molino, Fonseca, Hatonuevo, La Jagua del Pilar, Maicao, Manaure, Riohacha, San Juan del Cesar, Uribia, Urumita, Villanueva. Bioassays for temefos, malathion, and pirimiphos-methyl were carried out following the methodology of the World Health Organization, and the bottle technique using the guidance of the Centers for Disease Control and Prevention. Susceptibility to temefos was determined through the resistance ratio between lethal concentration 50 and lethal concentration 95; for the compounds temefos, malathion and pirimiphos-methyl, susceptibility was calculated using diagnostic dose and diagnostic time in the populations evaluated. Rockefeller susceptible strain was used as a control. Results. All evaluated populations of Ae. aegypti from La Guajira were found to be susceptible to temefos (ratio resistance to CL50<5.0; ratio resistance to CL95<5.0; 98 - 100 % mortality); pirimiphosmethyl (99 - 100 % mortality), and malathion (100 % mortality). Conclusion. Based on the results, the use of temefos, malathion, and pirimiphosmethyl is feasible for the control of Ae. aegypti in the evaluated populations.

Caracterización de bacilos gramnegativos multi-resistentes, aislados en pacientes hospitalizados en instituciones de salud de Barranquilla (Colombia) / Characterization of multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions in Barranquilla (Colombia)

Resumen Introducción: La resistencia a carbapenémicos en bacilos gramnegativos es un problema de salud pública mundial, debido a que se asocia con altas tasas de mortalidad, aumento en los niveles de resistencia a otros antimicrobianos, elevación en el potencial de diseminación e incremento en los costos de atención en salud. Objetivo: Caracterizar bacilos gramnegativos multirresistentes, aislados en pacientes hospitalizados en instituciones de salud de Barranquilla (Colombia). Material y Métodos: Estudio descriptivo acerca de la caracterización fenotípica y genotípica de la resistencia bacteriana en las infecciones asociadas a la atención en salud, mediada por carbapenemasas en aislados bacterianos enviados por los laboratorios pertenecientes a la red de laboratorios del Departamento del Atlántico. Resultados: La KPC fue la carbapenemasa más frecuente en las Enterobacterales (27,6%), predominando en Klebsiella pneumoniae (13,1%) sola y asociada a otras carbapenemasas. En Pseudomonas aeruginosa predominó la carbapenemasa VIM (32,8%) y la OXA en Acinetobacter baumannii (17,1%). Conclusión: Se encontró una amplia distribución de cepas multi-resistentes productoras de carbapenemasas en instituciones de salud de Barranquilla, las cuales expresaron los siguientes mecanismos de resistencia: KPC, VIM, NDM, OXA.

Abstract Background: The emergence of carbapenem resistant gramnegative bacilli has become a problem of public health worldwide, because it is associated with high mortality rates, increased levels of resistance to other antimicrobials, increased potential for dissemination transition and increase in health care costs. Aim: To characterize multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions of Barranquilla (Colombia). Methods: A descriptive study was conducted on the phenotypic and genotypic characterization of bacterial resistance in infections associated with health care, mediated by carbapenemases in bacterial isolates sent by laboratories belonging to the laboratory network of the Department of Atlántico. Results: KPC was the most frequent carbapenemase in Enterobacterales (27.6%), predominantly in Klebsiella pneumoniae (13.1%) alone and associated with other carbapenemases. In Pseudomonas aeruginosa, VIM carbapenemase (32.8%) predominated and OXA in Acinetobacter baumannii (17.1%). Conclusion: A wide distribution of multi-resistant strains producing carbapenemases in Atlantic health institutions was found, which expressed the following resistance mechanisms: KPC, VIM, NDM, OXA.

[Aedes aegypti larval infestation index and identification of awareness, attitudes and practices related to Dengue in tire shops in Atlántico, Colombia]. / Índices de infestación aédica e identificación de conocimientos, actitudes y prácticas sobre dengue en llanterías del Departamento del Atlántico, Colombia.

Objective To identify the awareness, attitudes and practices related to dengue in owners and workers of tire ships, as well as the levels of mosquito infestation in tire shops in Atlántico department - Colombia. Methods We conducted a descriptive study. The variables were described as percentages and measures of central tendency and dispersion. Index of larval infestation and containers were calculated in each of the municipalities studied. We visited and inspected 111 tire shops. 26.1 % (29/111) of these were found positive for Ae. aegypti larvae. The municipalities of Piojó, Santo Tomás, Santa Lucia, Sabanagrande and Luruaco were characterized by a higher larval infestation index. Results Regarding dengue, 90.9 % of respondents considered it a problem for them and their families. 94.6 % know that is transmitted by mosquitoes. 91.1 % know the vector larvae under the name "sarapico", 3.6 % as "gusarapo". 98.2 % felt that there is a relationship between the larva and Ae. aegypti mosquito. 100 % of participantes recognized tires to be a breeding for mosquitoes. 85.7% believed fever to be the most common symptom. 83 % reported accessing the health post to cure the disease. 90.8 % throw out unusable tires as if they were garbage. Conclusion In the population studied, there is good awareness of dengue and its vector. Nevertheless, there are problems related to attitudes and prevention practices.

Perfil de resistencia del Mycobacterium tuberculosis a fármacos antituberculosos de primera línea y sus combinaciones / Resistance profile of Mycobacterium tuberculosis to first-line antituberculosis drugs and their combinations

Introducción: En Colombia el control de la tuberculosis se ha visto amenazado por la resistencia a los fármacos antituberculosos y especialmente la tuberculosis multidrogorresistente. Objetivo: Determinar la resistencia global y perfiles de resistencia del Mycobacterium tuberculosis a fármacos antituberculosos de primera línea y combinaciones. Métodos: Estudio descriptivo, transversal, en el que se evaluaron 2 701 pacientes con tuberculosis en el Departamento del Atlántico (Colombia), durante los años 2011 a 2016. Se valoraron aspectos sociodemográficos, clínicos y condiciones de riesgo. Se realizó análisis de frecuencias relativas y absolutas, diferencia de proporciones ((2) y razón de prevalencias. Resultados: El 66,5 por ciento de los pacientes eran hombres, el 53 por ciento tenían entre 15 y 44 años de edad. El 47,34 por ciento con pérdida en el seguimiento y el 11,62 por ciento monorresistentes a isoniacida. La resistencia en casos nuevos fue 7,30 por ciento (IC95 por ciento: 6,3-8,5), para este grupo la multidrogorresistencia fue de 1,1 por ciento; mientras que en los previamente tratados la resistencia fue de 18,27 por ciento (IC95 por ciento: 15,6- 22,4) y la multidrogorresistencia de 5,7 por ciento. Los factores asociados a resistencia fueron presencia de VIH/TB (RP= 2,6; p= 0,000), otros factores inmunosupresores (RP= 3,5; p= 0,009), contacto de paciente con tuberculosis multidrogorresistente (RP= 16; p= 0,000) y caso previamente tratado (RP= 2,24; p= 0,00). Conclusiones: Se evidencia un descenso en la resistencia global a rifampicina e isoniacida, así como en la prevalencia multidrogorresistente tanto en casos nuevos como en previamente tratados en la población estudiada; lo que genera una línea base para la toma de decisiones que permita continuar mejorando la vigilancia y control de la resistencia del M. tuberculosis a fármacos de primera línea, debido a los nuevos retos que este microorganismo representa para la salud pública(AU)

Introduction: Tuberculosis control in Colombia has been hampered by resistance to antituberculosis drugs and particularly by multi-drug resistant tuberculosis. Objective: Determine the overall resistance and resistance profiles of Mycobacterium tuberculosis to first-line antituberculosis drugs and their combinations. Methods: A descriptive cross-sectional study was conducted of 2 701 tuberculosis patients from Atlántico Department in Colombia in the period 2011-2016. The evaluation included sociodemographic aspects, clinical characteristics and risk conditions. Data analysis was based on relative and absolute frequencies, proportion difference (x2) and prevalence ratio. Results: Of the total sample, 66.5 percent were men and 53 percent were aged 15-44 years. 47.34 percent were lost to follow-up and 11.62 percent were monoresistant to isoniazid. In new cases resistance was 7.30 percent (CI 95 percent: 6.3-8.5) and multi-drug resistance was 1.1 percent, whereas in previously treated cases resistance was 18.27 percent (CI 95 percent: 15.6-22.4) and multi-drug resistance was 5.7 percent. The factors associated to resistance were the presence of HIV/TB (AR= 2.6; p= 0.000), other immunosuppressive factors (AR= 3.5; p= 0.009), contact with multi-drug resistant tuberculosis patient (AR= 16; p= 0.000) and previously treated case (AR= 2.24; p= 0.00). Conclusions: A reduction is observed in overall resistance to rifampicin and isoniazid, as well as in the prevalence of multi-drug resistance, both in new cases and in previously treated cases, which creates a baseline for the taking of decisions aimed at the continuing improvement of the surveillance and control of M. tuberculosis resistance to first-line drugs, due to the new challenges posed by this microorganism to public health(AU)