Increasing transmission of dengue virus across ecologically diverse regions of Ecuador and associated risk factors

Abstract

The distribution and intensity of viral diseases transmitted by Aedes aegypti mosquitoes, including dengue, have rapidly increased over the last century. Here, we study dengue virus (DENV) transmission across the ecologically and demographically distinct regions or Ecuador. We analyzed province-level age-stratified dengue incidence data from 2000–2019 using catalytic models to estimate the force of infection of DENV over eight decades. We found that provinces established endemic DENV transmission at different time periods. Coastal provinces with the largest and most connected cities had the earliest and highest increase in DENV transmission, starting around 1980 and continuing to the present. In contrast, remote and rural areas with reduced access, like the northern coast and the Amazon regions, experienced a rise in DENV transmission and endemicity only in the last 10 to 20 years. The newly introduced chikungunya and Zika viruses have age-specific distributions of hospital-seeking cases consistent with recent emergence across all provinces. To evaluate factors associated with geographic differences in DENV transmission potential, we modeled the DENV vector risk using 11,693 Aedes aegypti presence points to the resolution of 1 hectare. In total, 56% of the population of Ecuador, including in provinces identified as having increasing DENV transmission in our models, live in areas with high risk of Aedes aegypti, with population size, trash collection, elevation, and access to water as important determinants. Our investigation serves as a case study of the changes driving the expansion of DENV and other arboviruses globally and suggest that control efforts should be expanded to semi-urban and rural areas and to historically isolated regions to counteract increasing dengue outbreaks.

Epidemiological, virological and clinical characterization of a Dengue/Zika outbreak in the Caribbean region of Costa Rica 2017–2018

“…Since we used pre-existing clinical data, the available information was incomplete, disregarding disease severity, high risk occupational groups and possible co-morbidities. Also, these two areas have been identified as hot spots for diseases by the National Ministry of Health, since they are near international borders, have a lot of immigration and temporal-work national migrating people and particular arbovirus-vector-climate/environmental characteristics ( Mayer et al., 2017 ; Weaver et al., 2018 ; Messina et al., 2019 ; Chan et al., 2022 ; de Souza and Weaver, 2024 ; Katzelnick et al., 2024 ). Therefore, it can be possible that the febrile like illness disease might be caused by something else that we did not test for.…”