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Dengue fever and Dengue Haemorrhagic fever (DF/DHF) is a mosquito-borne viral disease which is transmitted by Aedes mosquitoes. In recent years Dengue has become a major international public health concern. Dengue is found in tropical and sub-tropical regions around the world, predominately in urban and peri-urban areas. There are four sero-types of dengue virus, DEN-1; DEN-2; DEN-3; and DEN-4; all producing similar manifestations, which may be asymptomatic, undifferentiated fever, dengue fever (DF) and dengue haemorrhagic fever (DHF) / (Dengue Shock Syndrome-DSS).
Signs/Symptoms:
General Signs are Fever, abdominal pain, bleedings, low blood pressure, prostration, decreased urine volume, headache, myalgia, arthralgias, rashes and leucopenia or any other unusual features. It is generally an acute biphasic fever (390 C to 400 C) with headache, myalgia, arthralgias, rashes and leucopenia. Although DF is commonly benign, it may be an incapacitating disease with severe muscle and joint pain (break-bone fever), particularly in adults, and occasionally with unusual haemorrhage. DHF (Dengue haemorrhagic fever)is characterised by the acute onset of fever and associated non-specific constitutional signs and symptoms. There is a haemorrhagic diathesis and a tendency to develop fatal shock (dengue shock syndrome). Abnormal haemostasis and plasma leakage are the main patho-physiological changes, with thrombocytopenia and haemoconcentration. Hemorrhage: It may occur from the beginning with fever in case of Dengue Fever. But if this is found after a few days during a febrile period DHF is the possibility. DHF is a potentially dangerous condition threatening life. Hemorrhage may be of any description including prolongation of menstrual bleeding in case of female. The common sites are conjunctiva, skin, gum, nose and GI tract usually evident in the form of hematemesis, malena and hematokezia.
Prevalence:
Dengue haemorrhagic fever (DHF), a potentially lethal complication, was first recognized during the 1950s and is today a leading cause of childhood mortality in several Asian countries including our country. The global population at risk is estimated to be 2.5-3.0 billion in the urban areas of the tropical and sub-tropical regions. The disease is now endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, South-East Asia and the

Western Pacific. WHO currently estimates there may be 50 million cases of dengue infection worldwide every year. During epidemics of dengue, attack rates among susceptibles are often 40 – 50%, but may reach 80 – 90%. An estimated 500 000 cases of DHF require hospitalisation each year, of whom a very large proportion are children and roughly 5% die. Without proper treatment, DHF case fatality rates can exceed 20%. With modern intensive supportive therapy, the rate can be reduced to less than 1%.
Transmission:
Dengue viruses are transmitted to humans through the bites of infective female Aedes mosquitoes. Mosquitoes generally acquire the virus while feeding on the blood of an infected person. Once infective a mosquito is capable of transmitting the virus to susceptible individuals for the rest of its life, during probing and blood feeding. Infected female mosquitoes may also transmit the virus to the next generation of mosquitoes by transovarial transmission i.e. via its eggs. This mosquito breeds in small collection of clean water in domestic and peri-domestic containers.
Prevention and Control:
Now the question is what to do? Avoid mosquito bites, use long sleeve shirts and protective clothing ·Sleep under mosquito nets (preferably Insecticide treated nets) ·Destroy all domestic and peri-domestic breeding sources of Ae. aegypti mosquito (artificial containers, coconut shells, canes, used tires, earthen pots, flower vase, ant-traps etc.) ·Use of mats, coils, aerosol house spray, vaporising mosquito repellents etc. may be useful ·Use of Repellent: Essential oils from plant extracts (neem oil, lemon grass, citronella oil etc.) gives protection from mosquito bites.
Treatment:
No vaccine is available yet and there is no specific treatment. Hence DF/DHF control is primarily dependent on control of Aedes mosquitoes. However, careful clinical management of the symptoms save the lives of DHF patients. Still Physician can give few suggestion which includes : Complete bed rest is essential and patient should take sufficient fluid drinks (fruit juice, ORS etc.) to maintain fluid balance. Do not use ASPIRIN or NSAID-these drugs may trigger gastritis and provoke bleeding. Do not give antibiotic as these do not help Standby Emergency Treatment. Patient should be observed, fever to be lowered to the tolerable level with preferably room temperature tepid water sponging and or judicious use of paracetamol. Observation should be continued for two weeks for the danger.
Source: World Health Org, CDC, SDNP