Risk factors for a Dengue Fever diagnosis were travel to the Malay Peninsula (odds ratio [OR] 4.95; confidence interval [CI] 2.92 to 8.46), age 15-29 years (OR 3.03; CI 1.87 to 4.92), and travel duration >25 days (OR 8.75; CI 4.79 to 16.06).

i am not sure about how to calculate the cumulative risk, but it is definitely high alright...