dengue

http://www.telegraphindia.com/1160822/jsp/knowhow/story_103646.

Banish the bite

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Your Health - Dr. Gita Mathai

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Mosquito borne diseases usually arrive with the monsoon. And this year is no exception; there is a resurgence of dengue. And it is we who are to blame. If each citizen took his or her social responsibility seriously, our country would not need to be a marked in red on the WHO maps for dengue!

The disease is spread by the Aedes egypti mosquito, an attractive insect, recognisable by its tiger striped legs (unlike the boring grey of the Culex and Anopheles mosquitoes). It is a friendly insect, which does not stray far from its place of birth. It loves humans and their environment. Unlike the dawn and dusk attacks of other mosquitoes, it bites in the daytime too. It is ferocious when it attacks its prey. One bite is not enough. It either attacks the person repeatedly or bites several human beings in the vicinity. That is why several members of the family can get dengue at the same time.

Four to 10 days after the bite, the affected person suddenly develops a fever. He or she may also suffer from a red rash, headache, pain behind the eyes, in the joints and the abdomen, nausea, vomiting and throat pain. At this stage, it is difficult to distinguish dengue from other fevers.

Within a few days, the white blood cell and platelet counts drop. The liver enzymes can start to rise. The person starts to develop antibodies to the virus which are are detectable in 50 per cent of patients by days 3-5 after onset of illness, and in 99 per cent by day 10.

Keep dengue away

• As little as 2ml of water is enough for mosquitoes to lay eggs. Check your immediate environment for garbage like old tires, bottle caps, even leaves. • Tanks and ponds should be stocked with small, larva-eating fish like guppies. • Pouring a little kerosene or oil on stagnant water creates a thin film on the surface that prevents larvae from breathing. • Put up mosquito-proofing nets on windows and ventilators. Keep doors shut. Sleep inside mosquito nets. • Application of mosquito repellents on clothing (not skin) is effective for a few hours. Patches (mosquito tattoos) contain pure citronella extract and can be placed on clothing. Equal volumes of vanilla extract and water applied on the skin repels mosquitoes for an hour.

A person usually recovers spontaneously from the first attack of dengue. Immunity develops to that particular strain of virus (there are four strains) and lasts for a lifetime. Unfortunately, if there is a subsequent attack of dengue (a different strain), the body's immune reaction produces a severe response.

Complications are more likely in patients under the age of 12 and over the age of 60 years. The white blood cell and platelet counts drop. This can lead to bleeding from various places. If the bleeding occurs in the brain, it can be fatal. The liver becomes enlarged and the liver enzymes elevated. As more toxins are released into the blood, the blood vessels become permeable. Fluid leaks out of the blood vessels and accumulates in the abdomen and in the lungs. The circulating plasma volume is reduced and shock may develop. Eventually, as organs like the liver, heart and kidney do not get enough blood, they can fail.

There are no antibiotics that cure dengue. Treatment is mainly supportive, to reduce the temperature, (paracetemol 10-15mg/kg per dose every 4-6 hours in children and 500mg in adults). Aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids should be avoided.

Plenty of fluids should be given. In critically ill patients, admission to hospital and IV fluids and transfusions (of platelets) may be required. The exact criteria for platelet transfusion varies, and must be carefully done, as there is inherent risk associated with the transfusion of blood components.

There is as yet no vaccine against dengue. Ridding the house and its surroundings of the Aedes mosquito is the key to controlling dengue. Each individual needs to play a proactive role in this.

The writer is a paediatrician with a family practice at Vellore and author of Staying Healthy in Modern India. If you have any questions on health issues please write toyourhealthgm@yahoo.co.in