Dengue Fever: Causes and Symptoms
Dengue fever is a viral hemorrhagic fever caused by the bite of specific types of mosquitoes called Aedes aegypteii and Aedes albopictus. It's also called "Breakbone Fever" owing to the excruciating pains that it causes. The dengue virus (DENV) is a single stranded RNA positive-strand virus of the family Flaviviridae; genus Flavivirus. There are four serotypes of DENV. And infection with one serotype does not provide immunization against the other three. Infection with a second serotype after the initial infection is associated with more serious illness and complications. The Aedes mosquito is a fresh water dweller which typically bites at dawn and dusk. Dengue fever is endemic in the tropical areas, and every now and then there are epidemics of the disease in non-tropical areas of the world.
Dengue Fever lasts between 2 to 7 days, during which there is high-grade fever, intense muscle and joint pain, typical headache felt from behind the eyes and a maculopapular rash with spared areas in between the lesions. A dark red petechial rash may appear due to a decrease in the platelet count. Some people suffer symptoms of gastritis during the course of illness, with abdominal pain, nausea, vomiting and diarrhea in a varied combination. The fever ends with a biphasic period of small peaks at the end of illness. The number of Platelets drops along with the number of White Blood Cells, more specifically, the Neutrophills. This count keeps dropping till the fever subsides completely. A platelet count below 20,000 is considered as an indication of transfusion in the absence of hemorrhagic phenomena.
Dengue Hemorrhagic fever usually happens with the second or subsequent bout of the same illness. Reinfection with the same serotype cannot occur, so it's another type of the same virus that leads to a hypersensitivity response. High grade fever is present as well as aches and pains. In addition, there is spontaneous bleeding from the ears, nose, gums, eyes or stomach lining. Bruises may appear over the body without or as a result of minimal trauma. Platelet transfusions are given till the body starts producing it's own normal and functioning cells.
Dengue hemorrhagic fever can complicate into Dengue Shock Syndrome, in which the blood pressure drops due to leaky capillaries and reduced intravascular volume. All the signs and symptoms of Dengue Hemorrhagic Fever are there along with restlessness, reduced pulse pressure and altered consciousness with cold and clammy extremities.
Treatment is symptomatic. Only acetaminophen (Paracetamol) should be taken for fever as NSAIDS and Aspirin may cause bleeding. Intramuscular injections are contraindicated. Oral Rehydrating salts are advised to avoid dehydration. Platelet lowering and blood-thinning medication is stopped if previously prescribed. Use of an Insect Repellent and Mosquito Net can prevent future recurrence.
There are no vaccines available at present, but there is high paced work going on in this regard and some proposed vaccines are in phase I and II trials.
