He said dengue cases had fallen from over 3,500 cases a week to 2,247 cases two weeks ago.

“In this heat, containers become dry and there is no water for mosquitoes to breed in,” Hilmi was quoted by Malay Mail Online as saying.

“El Nino has reduced the number of cases, but we must remember that the larvae can live up to six months without water.”

Malaysians, he said, should keep their surroundings clean to help efforts to control dengue.

“Cleanliness and the people’s attitude have always been the biggest challenge for the ministry. People should clean up inside and outside their premises as well as the environment,” he said, adding that a concerted effort was required in order to control the incidence of dengue.

Hilmi said new chemicals had been introduced in fogging measures in order to combat the mosquitoes’ resistances to concoctions used previously, and some tested in hotspots had proven effective while others, not so.

“Adultciding, or killing the adult mosquitoes, is done using synthetic pyrethroids and organophosphates, while larviciding, or killing of larvae, is carried out using the chemical temephos or bacillus thuringiensis israelensis.”