Dengue fever are spread to people through the bite of an infected female Aedes mosquitoes (Aedes aegypti or Aedes albopictus) that feed both indoors and outdoors during the daytime (from dawn to dusk). Dengue outbreaks occurring in many parts of the world especially in urban area. Peak outbreak in Malaysia occurs in the late monsoon season (October through February in east peninsular Malaysia, Sabah, and Sarawak and July through August in west peninsular Malaysia). Aedes mosquitoes thrive in areas with standing water, including puddles, water tanks, containers and old tires. Urban and developing area with lack of reliable sanitation and regular garbage collection also contribute to the spread of the mosquitoes.
The incubation period for dengue infection is between 4–7 days. The symptoms varies between individual, range from no symptom to mild febrile illness to severe manifestation with multi-organ failure. Dengue fever is a dynamic disease, which means the clinical presentation changes as the disease progresses. After the incubation period, the illness begins abruptly and will be followed by three phases: febrile, critical and recovery phase.
During febrile phase, patient usually develop high grade fever suddenly lasted for 2 to 7 days often accompanied by redness over the face, body ache, joint pain, severe headache, pain behind the eyes (retro-orbital pain) and some may experience sore throat, red eyes, reduce appetite, nausea, vomiting and mild bleeding symptoms such as bruising and discolorations on the skin of various sizes (petechiae, ecchymosis, purpura), bleeding nose (epistaxis), bleeding gums, blood in the urine (haematuria) and vaginal bleeding.
Warning signs of progression to severe dengue usually occur in the late febrile phase around the time of defervescence (body temperature going down) usually between 3rd to 5th day of illness but may go up to 7th day when there is increase capillary permeability. Patient will either become better if no or minimal plasma leak occurs or worse if there is critical plasma volume loss. Patient may experience severe abdominal pain, persistent vomiting, lethargy and restlessness, difficulty breathing, dizziness when standing (due to drop in blood pressure) and liver enlargement. Some patient with poor oral intake will require intravenous fluid support. In severe case, patient may go into shock with confusion, coma and death if prompt fluid resuscitation not administered urgently.
Recovery phases occur after 2–4 days of defervescence where patient is feeling much better with return of appetite and improvement of haemodynamic status. Patient may also notice red spots appearing on the skin and increase urine volume.
Dengue is a public health concern and preventing dengue fever outbreaks are essential steps for keeping the community healthy. The most important step to prevent dengue infection is the control of mosquito population. This can be done by eliminating standing waters from around housing area such as plastic jars, old tires and flower pot. Other ways includes closing the window especially between dawn to dusk time and using mosquito nets. Avoid going out at night especially if there is a dengue outbreak in the area and use a long sleeve pants and shirt or using mosquito spray to prevent from mosquito bites.
If you have any symptoms to suggest dengue fever or concern about dengue, talk to our doctor for more information.