Event history analysis of dengue fever epidemic and inter-epidemic spells in Barbados, Brazil, and Thailand

OBJECTIVE: This study investigated meteorological and demographic factors affecting the length of dengue fever epidemics and the length of time between epidemics in Barbados, Brazil, and Thailand. METHODS: Region-specific meteorological and demographic data were collected for 104 sites from public sources. Fixed effects piecewise logistic event history analysis was used to quantify the effects of time-varying covariates on the duration of inter-epidemic spells and for the duration of epidemics. RESULTS: Mean monthly temperature was the most important factor affecting the duration of both inter-epidemic spells (β=0.543; confidence interval (CI) 0.4954, 0.5906) and epidemic spells (β=-0.648; CI -0.7553, -0.5405). Drought conditions increased the time between epidemics. Increased temperature hastened the onset of an epidemic, and during an epidemic, higher mean temperature increased the duration of the epidemic. CONCLUSIONS: By using a duration analysis, this study offers a novel approach for investigating the dynamics of dengue fever epidemiology. Furthermore, these results offer new insights into prior findings of a correlation between temperature and the geographic range and vector efficiency of dengue fever.