Beating the dengue menace

Professor Rohana Rajapaksa, Senior Professor in Entomology and Executive Director, Sri Lanka Council for Agricultural Research Policy

Sri Lanka has witnessed a dramatic increase in the number of dengue cases this year with more than 100 citizens succumbing to this menace. The Health Department should start a four-pronged approach to solve this problem through.

1. Preventive Surveillance checks

The Government with able assistance of provincial authorities should carry out regular surveillance island wide to check and destroy mosquito breeding grounds. All homes are to be checked in every three to six month cycle and all other premises including, Government and Commercial buildings every three months.

2. A National Mosquito Control effort

The Government should appoint an Inter Agency Task Force (IATF) to control dengue. At present this has become a monopoly with medical doctors playing a leading role. However, mosquitoes and their control is effectively dealt by the Entomologists and Collaboration with them will improve the co-ordination of dengue control among various agencies.

3. Targeted efforts

To pre empt the increase of dengue cases traditionally experienced in warmer months the Government should commence a search and destroy operations targeting the breeding habitats that is well identified.

4. Public out reach

The task force appointed should work closely with the community to keep public vigilant through target specific out reach programs, as an example messages through advertisements in newspapers, television programmes to alert messages to general public to wipe out breeding hot spots.

Traditional methods for controlling the spread of mosquito-borne disease, such as using bed nets and draining wetlands are ineffective for the Aedes Aegyptii mosquitoes that spread the dengue fever vitus because they bite during the day and thrive in urban areas.

Repellent repels mosquitoes that it reduces the chances of being bitten. In this light, repellent use offers individuals added protection against mosquito-borne diseases. In the community, it reduces the transmission of mosquito-borne diseases.

Internationally, multiple studies have shown DEET to be the most common ingredient for repellent products and is effective. There exist products with other active ingredients of varying effectiveness and work differently with an individual. One is citronella, which is effective for shorter durations and thus should be reapplied more frequently. Users should follow the instructions on the label. Bacillus thuriengiensis bacteria and a sand Gramular insecticide 1% Temephos have given excellent control in many countries.

Therefore, a need to adopt an integrated approach to mosquito control by including methods (environmental, biological and chemical) are safe, cost-effective and environmentally acceptable. A successful, sustainable Aegypti Control program must involve an agreement between government control agencies and the community.