Dengue Fever -Types & Symptoms

Dengue

Dengue fever is an infectious disease transmitted by mosquito and caused by any of four related dengue viruses. It is also called “break down fever” because it may cause many joint and muscle pain. It is transmitted by female Aedes mosquito. Since no vaccine is available, prevention is best option.

Occurrence

Dengue was geographically restricted until the middle of 20^th century. It was relatively the minor disease. During the 2^nd word war, Aedes mosquitoes were transported all over the world with cargo and played very critical role in the world. It was first documented in 1950’s during epidemics in Philippines and Thailand. WHO has estimated that 50-100 million infection every year.

Symptoms

After an infected mosquito bit, incubation period of 4-7 days is required before symptoms appear in the patient. Different dengue fever has different symptoms.

Types of dengue fever

These include:

1. Asymptomatic fever
2. Dengue fever
3. Dengue Haemorrhagic fever
4. Dengue shock syndrome

Asymptomatic fever

This is a type of fever which represents flu-like symptoms with mild fever.

Dengue fever

The temperature rises above 102* F with severe headache, backache, pain at back of the eyes and joints, with nausea and vomiting.

Dengue Haemorrhagic fever

It occurs less than 5% of patients. This is accompanied by extensive leakage of plasma. Very few causes show bleeding from nose, gums and rashes on the skin. There may be decrease in heart rate, weak pulse and cool extremities. There are rapid decreases in WBCs.

Dengue shock syndrome

When a dengue patient experiences shock, he has dengue shock syndrome. Both DHF and DSS patients need strict hospital monitoring and care.

Diagnosis

Complete blood count showing total number of RBCs, WBCs and platelets per unit volume of blood is basic diagnostic test.

Dengue virus

There are four types of viruses, DEN-1, Den-2, DEN-3, DEN-4which is called its serotypes.

• In humans

When infected female Aedes mosquito bites for a blood meal. It multiplies in body cells such as WBCs and symptoms appears after 4-7 days.

• In mosquito

When female Aedes bile the patient, it acquires virus. It multiply in the body of mosquito. The virus doesn’t cause any diseases in mosquito.

Dengue vector

The carrier of dengue virus inn Aedes mosquito. It is black and dark brown in colour (up to 10 mm in size) with white spots on body and legs. Only female can bite human as its mouth parts are designed for this purpose. This female mosquito need to suck blood to lay eggs.