Dengue is a mosquito-borne viral disease that has rapidly spread in all over the world in recent years. Dengue virus is transmitted by female mosquitoes mainly of the species Aedes aegypti.

Dengue is caused by a virus of the Flaviviridae family and there are four distinct, but closely related, serotypes of the virus that cause dengue (DENV-1, DENV-2, DENV-3 and DENV-4). 

The virus is transmitted to humans through the bites of infected female mosquitoes, primarily the Aedes aegypti mosquito. Dengue is frequently transported from one place to another by infected travelers.

Signs and symptoms of Dengue:

Dengue is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death. Symptoms usually last for 2–7 days, after an incubation period of 4–10 days after the bite from an infected mosquito.

Dengue should be suspected when a high fever (40°C/104°F) is accompanied by 2 of the following symptoms during the febrile phase:

• Severe headache
• Pain behind the eyes
• Muscle and joint pains
• Nausea
• Vomiting
• Swollen glands
• Rash

Severe Dengue

A patient enters what is called the critical phase normally about 3-7 days after illness onset. It is at this time, when the fever is dropping (below 38°C/100°F) in the patient, that warning signs associated with severe dengue can manifest. Severe dengue is a potentially fatal complication, due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment.

Warning signs that doctors should look for include:

• Severe abdominal pain
• Persistent vomiting
• Rapid breathing
• Bleeding gums
• Fatigue
• Restlessness
• Blood in vomit. 

 If patients manifest these symptoms during the critical phase, close observation for the next 24–48 hours is essential so that proper medical care can be provided, to avoid complications and risk of death.