30 August 2010
What is dengue fever?
Dengue is a mosquito–borne seasonal viral infection caused by four closely–related viruses (DENV 1–4) transmitted by the bite of a female mosquito of the genus Aedes. These domestic mosquitoes thriving around human habitations typically bite in daylight hours. They are easily recognized by their peculiar white spotted body and legs. In India, the outbreak of the disease usually occurs in the post–monsoon season when the mosquito population reaches its peak. Dengue cases are predominantly reported in urban and semi–urban areas. A more severe infection, known as dengue haemorrhagic fever (DHF), caused by the same virus, can be fatal if not detected at an early stage.
What are the symptoms of the disease?
After the virus enters the human body, it takes 4–6 days for the symptoms to become visible. The main symptoms of dengue are high fever (103–105 degrees Fahrenheit), severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding from nose or gums. Because of severe joint pain, dengue is also known as break–bone fever.
While the initial symptoms are similar to those in dengue, in dengue haemorrhagic fever, small purplish spots appear on the skin, which is caused by blood leaking out of the vessels. This is caused by the decrease in platelets, the cells in blood that help to stop bleeding. The smallest blood vessels (capillaries) become excessively permeable (leaky) allowing the fluid component to escape from the blood vessels to organs of the body. As the disease progresses, large bruises appear on the patient’s body and bleeding happens in the stomach with the patient vomiting blood. Severe haemorrhage may lead to failure of the circulatory system and shock, which might also cause death.
What is the treatment for dengue?
Like most viral diseases, there is no specific cure for dengue. Antibiotics do not help and generally paracetamol is the drug of choice to bring down fever and joint pain. Other medicines like aspirin and Brufen or any medicine that can decrease the platelet count should be avoided, since they can increase the risk of bleeding. As it has no specific medication, most patients with dengue fever can be treated at home. It is advised to take rest, drink plenty of fluids and eat nutritious diet and stay in constant touch with a physician.
DHF, however, requires hospitalization. Apart from this, it is also possible to get dengue more than once, as the disease is caused by four different but related strains of the virus and being affected by one strain offers no protection against the others.
Infected humans are the main carriers and multipliers of the virus, serving as a source of the virus for the mosquitoes. The viruses are transmitted from human to human through the bites of the female Aedes mosquitoes, which acquire it while feeding on the blood of an infected person. Hence the only way to prevent the outbreak of the disease is community–based mosquito control by eliminating the places where the mosquito lays its eggs. The mosquito primarily breeds in man–made containers like earthenware jars, metal drums and concrete cisterns, discarded plastic food containers, used automobile tyres and other items that collect rainwater. The best way to prevent the disease is by not allowing the mosquito to breed and using repellents for decreasing the risk of being bitten by mosquitoes.