Dengue is fast emerging pandemic-prone viral disease in many parts of the world. Dengue flourishes in urban poor areas, suburbs and the countryside but also affects more affluent neighbourhoods in tropical and subtropical countries.
Dengue is a mosquito-borne viral infection causing a severe flu-like illness and, sometimes causing a potentially lethal complication called severe dengue. The incidence of dengue has increased 30-fold over the last 50 years. Up to 50-100 million infections are now estimated to occur annually in over 100 endemic countries, putting almost half of the world’s population at risk.
The Mosquito:
The Aedes aegypti mosquito is the main vector that transmits the viruses that cause dengue. The viruses are passed on to humans through the bites of an infective female Aedes mosquito, which mainly acquires the virus while feeding on the blood of an infected person.
The Human:
Once infected, humans become the main carriers and multipliers of the virus, serving as a source of the virus for uninfected mosquitoes. The virus circulates in the blood of an infected person for 2-7 days, at approximately the same time that the person develops a fever. Patients who are already infected with the dengue virus can transmit the infection via Aedes mosquitoes after the first symptoms appear (during 4-5 days; maximum 12).
Symptoms:
A person infected by the dengue virus develops severe flu-like symptoms. The disease, also called ‘break-bone’ fever affects infants, children and adults alike and could be fatal. The clinical features of dengue fever vary according to the age of the patient.
Individuals should suspect dengue when a high fever (40°C/ 104°F) isaccompanied by two of the following symptoms:
- Severe headache
- Pain behind the eyes
- Nausea, Vomiting
- Swollen glands
- Muscle and joint pains
- Rash
Symptoms usually last for 2-7 days, after an incubation period of 4-10 days after the bite from an infected mosquito.Severe dengue is a potentially deadlycomplication due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment. The warning signs to look out for occur 3-7 days after the first symptoms in conjunction with a decrease in temperature (below 38°C/ 100°F) include:
- Severe abdominal pain
- Persistent vomiting
- Rapid breathing
- Bleeding gums
- Blood in vomit
- Fatigue, restlessness
The next 24-48 hours of the critical stage can be lethal; proper medical care is needed to avoid complications and risk of death.
Treatment:
- There is no specific treatment for dengue fever.
- Patients should seek medical advice, rest and drink plenty of fluids. Paracetamol can be taken to bring down fever and reduce joint pains. However, aspirin or ibuprofen should not be taken since they can increase the risk of bleeding.
- For severe dengue, medical care by physicians and nurses experienced with the effects and progression of the disease can frequently save lives. Maintenance of the patient’s circulating fluid volume is the central feature of such care.
Prevention and Control:
- Vector control is implemented using Integrated Vector Management (IVM) approach, which is a rational decision-making process for the optimal use of resources for vector control.
- IVM requires a management approach that improves the efficacy, cost-effectiveness, ecological soundness and sustainability of vector control interventions given the available tools and resources.
- 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.