Dengue fever is a self-limiting disease, which is transmitted by the bite of an infected female Aedes aegypti mosquito.

These mosquitoes gather around stagnant water. Hence, it is common for a surge in reports of dengue infections just after the monsoon.

Four persons reportedly died of dengue and 160 cases of infection were registered in various hospitals in Mumbai from June to September 2003. Most of the cases were reported from the suburbs of Malad and Borivali.

The Brihanmumbai Municipal Corporation is not sure how many of the people who died or those admitted in hospitals were actually infected by dengue.

BMC's Deputy Executive Health Officer Dr J G Thanekar said, "The four people may have died of dengue, but this could not be confirmed as none of them underwent the second (confirmatory) test. Rarely do people go in for a second blood test (as they are alerted by the first one and begin medication)."

In view of the dengue scare in the city, The BMC is organising a campaign to create awareness about the disease and the necessary precautions to prevent infection.

There are two types of dengue:
1) Classical Dengue Fever: Infected person complains of high fever, intense headache, muscle and joint pain, bitter taste, insomnia, anorexia, retro orbital pain and photophobia. Instances of it proving fatal are extremely low.

2) Dengue Haemorrhagic Fever or Dengue Shock Syndrome: Infected person complains of high fever, bleeding from nose, gums, ears, skin. May go into shock due to blood loss.

The fever comes within eight days of the mosquito bite.

How to detect if you are infected:
1) Serological test to detect IgM, IgG antibodies: IgM antibodies appear in blood at the end of eight days and persist for 1-3 months. It indicates acute infection. This is the test that most people undergo. It has an accuracy of 80-90% and is referred to as the preliminary test.

2) Isolation of virus in blood: This is a sophisticated test, conducted only by the Pune-based National Institute of Virology. Can be undertaken 10 days after the first blood test. Quite expensive, but it can confirm if the person is infected by dengue.

3) Polymerized Chain Reaction: This test involves amplification of the DNA (Deoxyribo Nucleic Acid). Very expensive and hence, undertaken only in rare cases.

The last two are undertaken to confirm infection.

How to avoid it:
1. Water from flower pots should be changed at least once a week
2. All containers storing water should be covered with a tight lid
3. Water stored in barrels, drums etc should be replaced by fresh stock (at least) once a week
4. All large water tanks, like those in buildings, should have single piece cast iron, tight fitting cover. A suitable ladder should be provided to enable civic staff to climb and examine the tanks at frequent intervals. The overflow pipe should be protected by a net that can keep away mosquitoes.
5. Discarded container-like objects like tyres, coconut shells, bottles, etc should be disposed off or destroyed.
6. Water fountains should be kept dry once a week
7. Surface wells should be well-maintained so that mosquitoes do not breed in the vicinity
8. Rain water collected on terraces/roofs should be cleared (at least) once a week

Dengue is also known as Break Bone Fever. If the infection is treated on time, the mortality rate is less then 15%.