Dengue fever occurs following the bite of an infected mosquito Aedes aegypti.This type of mosquito has a peculiar white spotted body and legs and is easy to recognize even by laymen. It breeds in clean water (see Question 20) and has a flight range of only 100 - 200 metres. The mosquito gets the Dengue virus after biting a human being infected with dengue virus.

During certain times of the year in certain areas like the Amazon ,some of the bigger cities have Dengue Fever but mainly in poorer and slum areas.

Dengue viruses spread to humans by the bite of female mosquitoes. These mosquitoes acquire the virus while feeding on the blood of an infected person. The virus circulates in the blood of infected humans for 2 –7 days leading to fever. Recovery from infection provided immunity against that particular virus but offers only partial protection against the other three viruses.

In infants and young children, dengue presents as a mild fever with rash. Older children and adults may have the classical symptoms of high fever, severe headache, pain behind the eyes, pain in the joints and muscles and rash. The pain in the back may be so severe that it is also called as backbreaking fever. Dengue fever is usually self-limiting. Dengue hemorrhagic fever is characterized by high fever, bleeding and liver enlargement.

Treatment for dengue and dengue hemorrhagic fever is supportive. Painkillers may be needed for severe bodyache. The patient should take adequate fluids to prevent dehydration. In case of bleeding or any other complications, patient may require hospitalization.

Dengue infection is caused by a virus. It occurs commonly as dengue fever. Occasionally the patient suffering from dengue may develop bleeding. Common sites for bleeding are nose, gums or skin. Sometimes, the patient may have coffee ground vomiting or black stools. This indicates bleeding in gastro intestinal tracts and it is serious. The patient with dengue who has bleeding has dengue haemorrhagic fever (DHF).

The characteristics of dengue that make it different from other causes of fever are the pain behind the eyes, severe pains in the muscles, severe joint pains, and skin rashes. These features make the diagnosis of suspected Dengue likely. The severe joint pains caused by DF is the reason why DF is also called break-bone fever.

Most patients with dengue fever can be treated at home. They should take rest, drink plenty of fluids that are available at home and eat nutritious diet. Whenever available, Oral Rehydration Salt/ORS (commoin treating diarrhoea) is preferable. Sufficient fluid intake is very important and becomes more important in case DF progresses into DHF or DSS where loss of body fluid / blood is the most salient feature.

The infection can become dangerous since it may cause damage to the blood vessels. The damage may range from increased permeability of the blood vessels, causing leakage of blood fluid/plasma into various organs to completely broken blood vessels that causes bleeding. The symptoms and signs of dengue hemorrhagic fever and dengue shock syndrome are related to damage to the blood vessels and derangement in functioning in components of blood that help it to clot.

People who suffer from dengue fever have no risk of death but some of them develop Dengue Hemorrhagic Fever or Dengue Shock Syndrome. In some of these cases death can occur. With proper treatment, the patients with Dengue hemorrhagic fever and dengue shock syndrome can recover fully. Good treatment provided in time can save most lives.

A vaccine has been developed to prevent dengue fever but it is still under trial. It is not yet available in the market. Scientific progress is likely to help in prevention of dengue fever by vaccination in the years to come.

Dengue haemorrhagic fever is a severe complication of the dengue virus. It is most commonly seen in children aged under 15 years but can occur in adults. It is more likely to occur if you have contracted dengue before. Symptoms for dengue haemorrhagic fever are the same as for dengue fever, but 2-5 days after the onset of fever, patients show a rapid deterioration in their condition. Cardiovascular disease, shock and sometimes death may follow.

Dengue does not spread directly from person to person. It is only spread through the bite of an infected mosquito.