Awareness about dengue vector, habitats and measures to prevent outbreak must

Islamabad: After confirmation of as many as 40 cases of dengue fever at public sector hospitals of the region, the chances of a possible outbreak of the infection have increased and the health experts believe that awareness among public about various aspects of the infection can play a vital role in checking spread of the infection.

People must be aware of the complete list of habitats of dengue fever vector to take proper action to eliminate adult mosquitoes and larvae of ‘aedes aegypti’, the vector that causes dengue fever. Also it is important for people to know that the maximum density of larvae of dengue fever vector is from July to October in this region of the country and it is time to take measures religiously to remove all possible breeding sites of mosquitoes inside and around their homes.

According to Additional District Health Officer at Islamabad Capital Territory Health Department Dr. Najeeb Durrani, individuals would better understand the course of action they must follow to avoid a possible outbreak of dengue fever by knowing which types of sites are examined by the district health departments in the region for elimination of dengue fever vector.

Water storages in houses, cement water tanks at rooftops, underground and earthenware water containers and plastic water containers all attract female mosquitoes to lay eggs and these all should be eliminated, he said.

He added that used wet tyres harbor mosquitoes and the larvae and pupae of mosquitoes. Large cement tanks like that of under construction buildings may serve as breeding sites for dengue vectors during their peak population season, from August to October.

Old utensils, broken furniture, toys and all like junk are sites for larvae breeding when rain water is collected in them. Anti-larval measures aimed at source reduction should be the main strategy and focus should be on man-made containers like earthenware jars, metal, plastic drums, concrete cisterns used for domestic water storage, discarded food containers, used automobile tyres, flower pots, vases and other items that collect rain water. Room coolers having ‘khass’, a net made from roots and are wet with automatic sprinkling of water is a favorite site for egg laying and larvae development, said Dr. Durrani, who is an epidemiologist and Member Global Outbreak Alert and Response Network (GOARN). He, however, said chemical control by fogging aimed at controlling the adult mosquitoes need not to be done for routine purpose as it is advised in emergency.

For indoor surveillance, individuals should properly cover the houses and fence the windows and doors and ensure installation of automatic door closers if possible, he said. People should regularly use mosquito repellents and carry out Insecticide residual Sprays (IRS) on weekly basis.

The peak season for transmission of dengue fever has already set in as the dengue fever vector, ‘aedes aegypti’ lay the first eggs of the year in the beginning of May and the mosquito density is maximal in early July, late August and early September while the egg laying activity remains until November though the larval density reaches to its peak in September, he said.

It is time for individuals to look for adult mosquitoes as these after getting a blood meal usually rest behind the curtains, under the beds, behind the furniture and in the bathrooms while waiting for few days for the eggs to mature. At this point in time the female mosquitoes avoid movement or flying and it is important now to kill the mosquitoes before they move out in search of moist place or water container to lay eggs, explained Dr. Durrani.