With the unseasonably hot weather giving a boost to mosquito growth, and a change in the predominant dengue viral strain, the authorities are warning that there could be a major epidemic of dengue this year.
So far, 6,400 people have been diagnosed with the mosquito-borne viral infection - three times the number seen at this time last year. If numbers continue, there could be 30,000 people infected this year, with many needing hospitalisation.
The authorities said eradication of mosquito breeding sites remains the number one weapon against the disease. Most found by inspectors have been inside homes, in pails, flower pot plates and trays.
A $200 fine was introduced on March 14 for anyone found to have mosquitoes breeding in their homes, not just in active dengue clusters.