Mosquitoes spreading dengue are formed in water storage units. If rain water is stored in sumps there may be a chance for breeding of dengue mosquitoes. Dengue is a very dangerous virus resulting in death. Here in our area (Hosur, Krishnagiri District, Tamil Nadu) dengue is spreading fast. In our house I have made arrangements to collect the rainwater in sumps. But I afraid will there be any dengue mosquitoes here - please advise.