Entomological characterization of Aedes mosquitoes and arbovirus detection in Ibagué, a Colombian city with co-circulation of Zika, dengue and chikungunya viruses

Abstract

Background Dengue, Zika and chikungunya are arboviruses of significant public health importance that are transmitted by Aedes aegypti and Aedes albopictus mosquitoes. In Colombia, where dengue is hyperendemic, and where chikungunya and Zika were introduced in the last decade, more than half of the population lives in areas at risk. The objective of this study was to characterize Aedes spp. vectors and study their natural infection with dengue, Zika and chikungunya in Ibagué, a Colombian city and capital of the department of Tolima, with case reports of simultaneous circulation of these three arboviruses. Methods Mosquito collections were carried out monthly between June 2018 and May 2019 in neighborhoods with different levels of socioeconomic status. We used the non-parametric Friedman, Mann–Whitney and Kruskal–Wallis tests to compare mosquito density distributions. We applied logistic regression analyses to identify associations between mosquito density and absence/presence of breeding sites, and the Spearman correlation coefficient to analyze the possible relationship between climatic variables and mosquito density. Results We collected Ae. aegypti in all sampled neighborhoods and found for the first time Ae. albopictus in the city of Ibagué. A greater abundance of mosquitoes was collected in neighborhoods displaying low compared to high socioeconomic status as well as in the intradomicile compared to the peridomestic space. Female mosquitoes predominated over males, and most of the test females had fed on human blood. In total, four Ae. aegypti pools (3%) were positive for dengue virus (serotype 1) and one pool for chikungunya virus (0.8%). Interestingly, infected females were only collected in neighborhoods of low socioeconomic status, and mostly in the intradomicile space. Conclusions We confirmed the co-circulation of dengue (serotype 1) and chikungunya viruses in the Ae. aegypti population in Ibagué. However, Zika virus was not detected in any mosquito sample, 3 years after its introduction into the country. The positivity for dengue and chikungunya viruses, predominance of mosquitoes in the intradomicile space and the high proportion of females fed on humans highlight the high risk for arbovirus transmission in Ibagué, but may also provide an opportunity for establishing effective control strategies. Graphical abstract

Determinants of Aedes mosquito density as an indicator of arbovirus transmission risk in three sites affected by co-circulation of globally spreading arboviruses in Colombia, Ecuador and Argentina

“…We found that wealthier households where occupants displayed higher knowledge of arboviruses were associated with lower Aedes density. Household wealth is widely known to affect mosquito vector density, potentially through better access to mosquito control methods [ 22 , 26 , 34 , 43 ], and the effect of knowledge about mosquito vectors and arboviruses on household mosquito vector density and arboviral disease risk has also been the subject of many studies [ 27 , 44 , 45 ]. We also found major effects of presence of decorative vegetation and landscape elements around the household.…”

“…Identified specimens were then stored in RNAlater (Thermo Fisher Scientific, Waltham, MA, USA) and transported to a laboratory for subsequent processing and molecular analysis for virus detection; the results of these analyses are to be presented in separate papers (e.g. [ 34 ]).…”

Arbovirus infection in Aedes aegypti from different departments of Colombia

“…Also, studies of natural infection in Aedes mosquitoes in central departments of the country in 2016 reported high rates of DENV-2 infection in A. aegypti, possibly associated with the epidemic that occurred during that year (Pérez-Castro et al, 2016;Ruiz-López et al, 2016;Gómez-Palacio et al, 2017;Pérez-Pérez et al, 2017). Similarly, reports of infection in Aedes during 2018 and 2019 showed DENV-1 infections related to the latest outbreak in Colombia (Martínez et al, 2020;Carrasquilla et al, 2021). Given this scenario, our findings on the frequency of infection in A. aegypti could be associated with this national trend and reveal the predominant serotype transition from serotype DENV-1 to DENV-2 in all departments, suggesting that the latter serotype could be the cause of the next outbreak in the country.…”

“…In recent years, a gradual decrease in the notification of Chikungunya and Zika cases has been observed (Instituto Nacional De Salud, 2020, 2022, with a low incidence in 2020 and 2021 (0.3-0.5 cases per 100.000 inhab) for both arboviruses. The reduced circulation of these arboviruses may be associated with low rates of susceptible population turnover and reintroduction (Carrasquilla et al, 2021), which limits the circulation of these viruses in humans and Aedes.…”

“…The lack of accurate and timely knowledge about the molecular epidemiology of arboviruses of public health importance, particularly in the mosquito vector, has limited the prediction of the genuine risk of emergence and spread of new arboviral strains in human populations. In Colombia and the Americas, studies on entomological characterization of Aedes mosquitoes and detection of arboviruses are scarce (Jaimes-Duenez et al, 2015;Pena-Garcia et al, 2016;Pérez-Castro et al, 2016;Peña-Garcia et al, 2017;Martínez et al, 2020;Carrasquilla et al, 2021), which has implications for effective arboviral control strategies. Therefore, this study aimed to describe the frequency of infection and/or natural co-infection by DENV, CHIKV, and ZIKV in Aedes spp.…”