Epidemiology of dengue and other arboviruses in a cohort of school children and their families in Yucatan, Mexico: Baseline and first year follow-up

Abstract

Dengue is the most prevalent mosquito-borne viral disease of humans and is caused by the four serotypes of dengue virus. To estimate the incidence of dengue and other arboviruses, we analyzed the baseline and first year follow-up of a prospective school-based cohort study and their families in three cities in the state of Yucatan, Mexico. Through enhanced surveillance activities, acute febrile illnesses in the participants were detected and yearly blood samples were collected to evaluate dengue infection incidence. A Cox model was fitted to identify hazard ratios of arboviral infections in the first year of follow-up of the cohort. The incidence of dengue symptomatic infections observed during the first year of follow-up (2015–2016) was 3.5 cases per 1,000 person-years (95% CI: 1.9, 5.9). The incidence of dengue infections was 33.9 infections per 1,000 person-years (95% CI: 31.7, 48.0). The majority of dengue infections and seroconversions were observed in the younger age groups (≤ 14 years old). Other arboviruses were circulating in the state of Yucatan during the study period. The incidence of symptomatic chikungunya infections was 8.6 per 1,000 person-years (95% CI: 5.8, 12.3) and the incidence of symptomatic Zika infections was 2.3 per 1,000 person-years (95% CI: 0.9, 4.5). Our model shows that having a dengue infection during the first year of follow-up was significantly associated with being female, living in Ticul or Progreso, and being dengue naïve at baseline. Age was not significantly associated with the outcome, it was confounded by prior immunity to dengue that increases with age. This is the first report of a cohort in Latin America that provides incidence estimates of the three arboviruses co-circulating in all age groups. This study provides important information for understanding the epidemiology of dengue and other arboviruses and better informing public health policies.

Author summary

Dengue is a major public health problem worldwide. The burden of dengue in Latin America is been increasing in the last years and Mexico is one of the countries with the highest burden in this region. To better understand the transmission of dengue in Mexico we established a school-based prospective cohort study of dengue virus infection in children and their families in three cities in the state of Yucatan, Mexico. In this article we show that around 70% of the cohort population has prior immunity to dengue. Also that the rate of dengue cases varied among cities and we also confirm the circulation of chikungunya and Zika virus in the cohort participants during the first year of follow-up. We found evidence that having prior dengue immunity might protect again Zika symptomatic infections. The results of this study will be useful for the scientific community and policy makers from Mexico and other countries in Latin America to properly plan and evaluate control strategies and interventions like vector control and vaccines.