downtoearth-subscribe

Tackling dengue

HAVING learnt from past experience, health officials and the government are all set tackle the threat of dengue in Delhi this year. A proceedings of a conference on "Dengue outbreak in Delhi:1996", organised by the Ranbaxy Science Foundation in December 1996,were released by Delhi health minister Harsh Vardhan on May 15, 1997.

Dengue fever led to the death of 453 people in Delhi in 1996. In all, 10,052 cases were reported, revealing gross inadequacies in prevention and control methods. Both the government and major medical institutions such as the All India Institute of Medical Sciences (AIIMS) failed to take note of the seriousness of the problem. The situation worsened due to lack of public awareness.

Dengue infections can range from mild to moderate, while severe cases can lead to death. Of the four known strains of the virus - DEN- 1, DEN-2, DEN-3 and DEN-4 - the DEN-2 strain is responsible for dengue haemorrhagic fever, the most severe form of the disease. The symptoms in the classical form - dengue fever - are high fever, headache, pain in the joints and muscles, and an outbreak of rashes.

Participants at the conference stressed the need for prevention of dengue fever, which is difficult to manage even under professional supervision. As V Ramalingswami, National Research Professor at AIIMS, pointed out, body fluids need to be replenished up to three or four times the normal requirement.

The mosquito which transmits the virus feeds by day and breeds in containers like storage tanks, water coolers and earthen pots. According to V P Sharma, director of the Malaria Research Centre, the female mosquito lays 50-100 eggs every alternate day. Since the eggs are glued to the surface of the containers, their removal requires scrubbing. Since the mosquito has a short life cycle and does not fly any great distance to feed, it affects only the nearest available humans. So the inmates of a house where the mosquito has been breeding are most vulnerable to the disease it spreads.

To prevent dengue, breeding sites should be destroyed and it should be ensured that the mosquito does not bite humans. Medical experts opine that a national surveillance system should be set up to detect early cases of dengue. Guidelines for the methods of blood sample collection, storage and transport will have to be standardised and made available to all major hospitals. Researchers in Thailand are working on a vaccine that may prove effective against all the four strains of the virus. The Colorado State University in the US has also conducted genetic engineering on mosquitoes to produce breeds that resist pathogenic viruses, thus making them unable to transmit diseases.

Related Content