Dengue is found in tropical and sub-tropical regions around the world, predominantly in urban and semi-urban areas.

Dengue hemorrhagic fever (DHF) was first recognized in the 1950s during the Dengue epidemics in the Philippines and Thailand, but today DHF affects most Asian countries and has become a leading cause of hospitalization and death among children in several of them.

There are four distinct, but closely related, viruses that cause Dengue. Recovery from infection by one provides lifelong immunity against that serotype but confers only partial and transient protection against subsequent infection by the other three. There is good evidence that sequential infection increases the risk of more serious disease resulting in DHF.

How Dengue is transmitted?

Dengue is transmitted by the bite of infective female Aedes mosquitoes.

What are the sign and symptoms of Dengue?
Signs and symptoms of Dengue include the followings.

■ High grade fever with chills
■ Severe body ache or myalgia
■ Rashes on the body. Dengue rash typically appears on lower limbs and trunk.
■ Headache, eye pain and ear pain.
■ Hemorrhagic tendency it is manifested by sudden and easy bruising,    
   bleeding from gums, bleeding from injection site, passing blood in vomit or  stools.
■ Increase or decrease in hematocrit level by 20%
■ Decrease in number of thrombocytes thereby increasing tendency to bleed.

Complications of Dengue gives rise to DENGUE SHOCK SYNDROME. It is characterized by

► Cold clammy skin with restlessness
► Cold sweat
► Rapid feeble pulse > 100/min
► Rapid breathing thereby increasing respiratory rate.
► Hypotension or low blood pressure.



What are the investigations to confirm the diagnosis of Dengue?

Serological profile of blood and PCR technique is used for confirmation of the diagnosis of Dengue.

What is the treatment of Dengue?

The mainstay treatment of Dengue is supportive therapy.

● Complete bed rest along with plenty of oral fluids.
● If patient is unable to take orally then IV fluids are given to maintain      hemoconcentration.
● Platelet counts are given very high importance. If platelet count drops below  20,000     and even if there is no evidence of bleeding, platelet transfusion is     given.
● If there is history of passing dark colored stools or brown colored vomit then  also        platelet transfusion is given.
● Aspirin and NSAIDS are absolute contraindicated in Dengue.

What are the complications of Dengue?

● Hemorrhagic shock
● Death.

How can we prevent Dengue spread?

At present, the only method of controlling or preventing Dengue is to combat the vector mosquitoes.

Mosquitoes breed primarily in man-made containers like earthenware jars, metal drums and concrete cisterns used for domestic water storage, as well as discarded plastic food containers, used automobile tyres and other items that collect rainwater. In Africa it also breeds extensively in natural habitats such as tree holes and leaf axils.

Proper solid waste disposal and improved water storage practices, including covering containers to prevent access by egg laying female mosquitoes are among methods that are encouraged through community-based programmes.

 

During outbreaks, emergency control measures may also include the application of insecticides as space sprays to kill adult mosquitoes using portable or truck-mounted machines or even aircraft. However, the killing effect is only transient, variable in its effectiveness because the aerosol droplets may not penetrate indoors to microhabitats where adult mosquitoes are sequestered, and the procedure is costly and operationally very demanding.

Personal protection

Personal prevention consists of the use of mosquito nets, repellents containing NNDB or DEET etc.