Dengue (pronounced as Dengii) fever is caused by a virus. Four types of viruses called DENV 1 to 4 are seen. These are spread while a mosquito (Aedes egypticus) is biting a human being. This mosquito bites during the day and breeds in stagnant water. It is widespread throughout India and South East Asia. About 400 million cases occur every year in the world.
Most of the infections do not produce symptoms. About ¼ may cause fever usually in children and young adults. Dengue infection can recur if a person is infected with the same type of virus as immunity decreases with time.
Common manifestations :
These begin 3-14 days after the bite. The symptoms are
- Fever with temp of > 38.5 o C
- Headache, pain behind the eyes
- Pain in the back (at times severe : break bone fever)
- Pain in the abdomen or chest
- Mild pain in the joints.
All symptoms need not occur simultaneously. The doctors or patient may notice a pink rash which fades temporarily on pressing the area. In severe cases vomiting , tiredness, abdominal pains may start.
Pin point like bright red spots or blotches of reddish areas may occur. Complicated cases are called Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS).
In DHF Bleeding may occur from nose, in stools or vomits or periods may be heavy in woman. Bleeding may be very heavy at times. Abdomen and Chest collect fluids (called ascites and pleural effusion).
In DSS life threatening situation occurs with fall in blood pressure and involvement of other vital organs. Blood pressure (systolic) is below 80 mm Hg in children under 5 yrs and < 90 mm in those older then 5 yrs.
Laboratory Tests :
In blood counts platelets and WBCs may be low. Hb may rise in DHF due to leakage of plasma under the skin or in lungs and abdomen.
Dengue is diagnosed by Direct tests showing Virus particle or its part (antigen or genome), or indirect tests (IgG and IgM antibodies in serum). Direct tests are more accurate but costlier.
Milder cases require only symptomatic treatment. In complicated cases hospitalisation and monitoring of platelets, bleeding, blood pressure, vital organ function is carried out.
Patients may require IV fluids, Blood and their components (platelets etc) After a critical phase of 24 to 48 hrs, patient may start recovering. Prevention of Dengue is by antimosquito measures and preventing mosquito bites esp in young children and adults.