Dengue fever is a benign acute febrile syndrome occurring in tropical regions, which is the most important mosquito (Aedes aegypti), transmitted viral disease. The virus causes Dengue shock syndrome in 20-30% of infected cases. There are four types (known as "serotypes") of dengue.
Infection and recovery from one type of dengue does not protect a person from another type. Dengue Hemorrhagic Shock Syndrome (DHSS) is a dangerous implication in which fever is followed by the collapse with shock, decreased blood pressure and signs of hemorrhage. The shock increases the production of the hormone adrenaline, which in turn increases the heartbeat. Blood is pumped faster resulting in more hemorrhage and the heart becomes overworked. Dengue infection weakens the wall of the blood vessels resulting in plasma leakage; disease suppresses the production of platelets that help in the clotting of blood. If the process continues unchecked, the volume of blood decreases due to leakage, the blood pressure drops and the platelet count reduces. Bleeding occurs in patients with severe shock syndrome. "The fever lasts about seven days and the patient has severe body ache. It's in fact known as a bone-breaking fever. But dengue hemorrhagic fever is a far more serious condition, which generally occurs in patients who have already experienced dengue," explains Dr Pradeep Seth, Microbiologist.
The severity of the disease increases each time contracted with the dengue virus. The patient may also develop stomach aches and vomiting occurs. Flushing of the skin may occur on the palms, soles of feet, face and neck with red spots may appear on the skin. These indicate internal bleeding, which is on of the symptoms of dengue with aching joints, which may appear swollen. The most dangerous period is the leakage phase, which usually takes place around the fourth or fifth day. The patient develops abdominal pains with significant vomiting and the colour change in the vomit to red or black or brown indicates bleeding in the stomach. More red spots may develop on the skin and the stool will also be black in colour, which indicates internal bleeding.
The person suspected of having dengue should take bed rest and be given plenty of fluids to drink. The affected patient should not be allowed to go to school or work as this would enable the dengue virus to be transmitted to more people, by mosquito transmission. No drugs (including Aspirin) containing Salycilates should be given to the patient and the symptoms should be closely monitored. Treatment of dengue fever is nonspecific and supportive care. Treatment involves non-salicylate antipyretic drug, oxygen and electrolyte and fluid replacements. Red blood cell and platelet transfusions and fresh plasma are indicated for severe bleeding and decreasing hematocrit values.
No dengue vaccine is available and recently attenuated candidate vaccine viruses have been developed. Efficacy trials in human volunteers have yet to be initiated and research is also being conducted to develop second-generation recombinant vaccine. Till, development of an effective vaccine, the only way to escape dengue infection is to remove water stagnation and eradicate mosquitoes.
Dengue in India:
Dengue fever is one of the oldest arthropod borne viral disease know in India. The first known epidemic of Dengue occurred in 1779-1780 in Asia, Africa, and North America. During 1991-1995, a total of 18 Dengue Fever outbreaks were reported from different parts of the country, and the trend shows that the disease is occurring with increased frequency. A widespread outbreak of disease occurred in Delhi and its surrounding areas during 1996. Similar outbreaks were also reported from the neighboring state of Haryana. In October 1996, a suspected dengue/DHF outbreak was reported from Ludhiana city of Punjab state.
This year, In Kolkata, 13 deaths and more than 71 people were infected due to dengue fever in Kolkata and its suburbs in the last one week, which has alarmed the West Bengal and Kolkata. Of the 13 deaths two of the deaths were reported from Dum Dum and the rest, from the Prince Anwar Shah Road, Ghulam Hossain Road, Amherst Street and Garden Reach areas in the city. The health authorities of Kolkata Municipal Corporation confirmed that 180 out of 188 suspected dengue patients have tested positive.
In New Delhi, just after the start of the monsoon this year, three deaths have been reported with 26 people affected in the last two weeks. Most of the cases have been reported from the outer Delhi area. Out of the 34 cases reported this year, 22 are from here. A team of 1,500 people has also been constituted to go from house to house and analyse stagnant water. Last year, more than 7,000 residential areas in Delhi were under the scanner for dengue cases. This year, that number is expected to increase to 10,000 areas.
In Delhi during, 1996 with 16,517 cases being reported from across the country, out of which 10,252 were reported from Delhi alone. The death toll then was 545, of these 423 were in Delhi alone.
The year 2003 saw yet another outbreak with over 12,000 cases being reported from all over the country, resulting in 215 deaths. Delhi was again the worst affected with over 2,800 cases and 34 deaths. N.K. Yadav, deputy health officer, Municipal Corporation of Delhi (MCD), claims that the situation is under control.
The Municipal Corporation has hired 1,055 more health workers to check and disinfect places where mosquitoes are breeding in homes and neighborhoods across the city and they have identified 10,326 houses as mosquito breeders, compared to some 7,000 last year. "We are also constantly in touch with the Resident Welfare Associations (RWA) to spread awareness in colonies. Posters and pamphlets are also distributed in all parts of the capital," Yadav added.
The effective control of dengue will be possible only by blocking the breeding and spread of the mosquitoes, which requires cooperation, and conscious of the people to tackle the dengue effectively.