Dengue is a fast emerging pandemic-prone viral disease in many parts of the world, and it flourishes in urban poor areas, suburbs and the countryside but also affects more affluent neighbourhoods in tropical and subtropical countries. The mosquito-borne viral infection causes severe flu-like illness and, sometimes causes a potentially lethal complication called severe dengue.
Over the last 50 years, the incidence of dengue has increased 30-fold, and up to 50-100 million infections are now estimated to occur annually in over 100 endemic countries. The increase in infections puts almost half of the world's population at risk.
In the case of severe dengue (previously known as dengue haemorrhagic fever), it was first recognized in the 1950s during dengue epidemics in the Philippines and Thailand. Today it affects Asian and Latin American countries and has become a leading cause of hospitalization and death among children and adults in these regions. It leads to bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs.
HOW IT SPREADS:
The full life cycle of dengue fever virus involves the role of mosquito as a transmitter (or vector) and humans as the main victim and source of infection. It is spread by several species of female mosquitoes of the Aedes type, principally A. aegypti. The viruses are passed on to humans through the bites of an infected female Aedes mosquito, which mainly acquires the virus while feeding on the blood of an infected person.
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).
A person infected by the dengue virus develops severe flu-like symptoms, and the disease, also called break-bone fever, affects infants, children and adults alike and could be fatal. The symptoms of dengue may vary according to the age of the patient, and will begin showing three to fourteen days after a bite from an infected mosquito. A person who has been infected will have a high fever (40°C/104°F) accompanied by severe headache, pain behind the eyes, nausea, vomiting, swollen glands, muscle and joint pain, and a characteristic skin rash.
If the person is suffering from severe dengue, there would be a deadly complication due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment. The symptoms appear 3-7 days after the first symptoms in conjunction with a decrease in temperature (below 38°C/100°F) and severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, blood in vomit, fatigue, and 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.
There is no specific treatment for dengue fever, but what the patients can do is 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. Maintenance of the patient's circulating fluid volume is the central feature of such care. For more severe cases, a blood transfusion may be required.
Other methods to prevent the spread of the disease include destroying mosquito habitat and limiting exposure to bites, which can be done by getting rid of or covering standing water and wearing clothes that cover much of the body.