During a dengue outbreak investigation in a coastal town in Tamil Nadu, epidemiologists identify that 60% of symptomatic dengue cases occur in children aged 5–14 years, while 35% occur in adults aged 25–45 years, and only 5% in elderly (>60 years). Serological surveys show that 85% of the elderly population have dengue-specific IgG antibodies, compared to 40% in the 25–45 age group and 15% in children. What does this age-stratified seroprevalence pattern most likely indicate about the dengue epidemiology in this town?