There are 5 strains of DF (possibly 6 - they think a new one has emerged) - and although you can get each strain only once, each successive infection increases the chance you'll progress to the much more serious (and often fatal) Dengue Haemorrhagic Fever. Bleeding internally and from the eyes and ears doesn't sound like fun.
Also, there's no vaccine for DF, your only precaution is to avoid being bitten by mosquitoes. That means long sleeve, long trousers preferably light-coloured loose-fitting clothes. Lots of DEET repellant on the remaining exposed skin. Sleep under mosquito nets, and I'd suggest burning insect repellant coils at your feet whenever seated in a restaurant. At your accommodation, tip out any bowls/containers of stagnant water you find.
If you get DF again you might want to think about whether you want to risk a complicated disease by continuing your trip.
From an insurance aspect (and I'm the safety guy, not the insurance bloke) you need to pick up the phone and give them a call about this. There're lots of factors, such as "where you showing DF symptoms before you bought your policy or after?" and if you don't take proper precautions whether you'll be fully covered. Complicated stuff you need to discuss with the proper people. almost 8 years ago