Vector competence analysis of two Aedes aegypti lineages from Bello, Colombia, reveals that they are affected similarly by dengue-2 virus infection.

Dengue is the second most prevalent vector-borne disease after malaria in Colombia. It is caused by dengue virus, an arbovirus that exhibits high epidemic power, which is evidenced by its occurrence in more than 80% of the country, largely because of the extensive dispersion of the mosquito vector Aedes aegypti. The existence of two lineages of Ae. aegypti has been proposed based on genetic differences at the mitochondrial level, and they have been reported to circulate in similar proportions in the municipality of Bello (Colombia). It has been suggested that the differentiation of these lineages could influence features such as vector competence (VC) and life table. With the aim of testing this hypothesis, female mosquitoes from both lineages collected from Bello were orally challenged with dengue virus serotype 2 (strain D2-HAN) to measure infection, dissemination, survival and fecundity. Analysis of VC showed an increase in viral titer over time; however, no significant differences were observed between the lineages. The survival rate was not different between the infected lineages, but comparing lineages, it was lower in infected mosquitoes, which may affect the intensity of transmission. Finally, we conclude that the genetic differentiation of Ae. aegypti into lineages did not confer differences in epidemiological status when the mosquitoes were infected with this D2 serotype strain.

Risk Factors Associated with Dengue Transmission and Spatial Distribution of High Seroprevalence in Schoolchildren from the Urban Area of Medellin, Colombia.

Dengue fever is an increasing health problem in tropical and subtropical regions. During 2010 in Medellin, the younger population presented a particularly high dengue incidence rate. This study estimated dengue virus (DENV) transmission in schoolchildren (aged 5-19 years) in Medellin from 2010 to 2012. A longitudinal serological survey (IgG) and spatial analysis were conducted to determine the distribution of DENV seroprevalence. A total of 4,385 schoolchildren participated for at least one year. Dengue seroprevalence significantly increased during the studied period (53.8% to 64.6%; p < 0.001). A significantly higher seroconversion rate was observed in 2010-2011 (16.8%) compared to 2011-2012 (7.8%). Multivariate regression analysis showed that the main factor associated with the seroprevalence was the aging. Furthermore, in 2010, patients with high socioeconomic status presented a lower risk. Predominant multitypic and DENV4 monotypic antibody responses were demonstrated. Geostatistical analysis evidenced a temporal clustering distribution of DENV seroprevalence in 2010. Population density and Ae. aegypti House Index were significantly correlated with the observed pattern. This study revealed high DENV transmission in schoolchildren determined as "sentinel population." High DENV risk was found in districts with combined poorly socioeconomic conditions and densest human and mosquito populations. These findings may allow to target population for effective prevention and vaccination campaigns.