Dengue is a mosquito-borne seasonal viral infection caused by any of four closely related viruses (DENV 1-4). The virus is transmitted by a bite of female mosquito of any of two species of mosquitoes of the genus Aedes. The mosquito, which typically bites humans in the daylight hours, can be easily recognized because of its peculiar white spotted body and legs. Outbreak of the disease typically occurs in summer season when the mosquito population reaches its peak. It occurs widely in tropical and subtropical areas in Asia, Africa, Central and South America. Unlike malaria, which is a major health concern in rural areas, dengue is equally prevalent in the urban areas too. In fact, it is predominantly reported in urban and semi-urban areas. WHO estimates that there may be 50 million dengue infections worldwide every year. A severe form of the infection is known as dengue hemorrhagic fever (DHF). DHF can be fatal if not detected.
Symptoms of Dengue
After its entry into patient’s body, the virus multiplies to reach sufficient numbers to cause the symptoms. This process might take 4-6 days after which the symptoms become visible. The main symptoms of dengue are high fever (103-105 degrees Fahrenheit), severe headache (mostly in the forehead), severe pain behind the eyes, joint pain, muscle and bone pain, rashes, and mild bleeding from nose or gums. Because of the severe joint pain, dengue is also known as break-bone fever. Typically, younger children and those with their first dengue infection have a milder illness than older children and adults.
DHF is characterized by a fever that lasts for 2 to 7 days, with general signs and symptoms consistent with dengue fever. In addition to these symptoms, if a patient suspected with dengue experiences decrease in platelets or an increase in blood haematocrit, it becomes more certain that the patient is suffering from the infection.
Platelets are cells in blood that help to stop bleeding, while haematocrit indicates thickness of blood. The smallest blood vessels become excessively permeable allowing fluid component to escape from blood vessels to organs of the body.
This may lead to failure of circulatory system, which might also cause death.
Treatment of Dengue
- Like in most viral diseases, there is no specific cure for dengue. Antibiotics do not help and paracetamol is the drug of choice to bring down fever and joint pain.
- Other medicines such as Aspirin and Ibuprofen or any medicine that can decrease platelet count should be avoided since they can increase the risk of bleeding.
- As it has no specific medication, most dengue patients can be treated at home.
Aedes aegypti mosquitoes, which spread Dengue virus prefer to breed in man made containers. It can be recognized by white markings on leg. Dengue mosquito is a day biting mosquito. The dengue viruses are the only known arboviruses that have fully adapted to humans and do not need an animal reservoir, although dengue has been observed to also circulate in nonhuman primates. They are transmitted from human-to-human by the urban-dwelling Aedes aegypti mosquito, which has adapted to humans, laying their eggs in artificial containers in and around houses and feeding only on humans, and by Ae albopictus (Asian tiger mosquito) and Ae polynesiensis. These latter mosquitoes feed on birds, reptiles, rats, cows, and humans. DV may be transmitted vertically from the female mosquito to her offspring. Most cases of transmission from human-to-human are through female mosquitoes which previously became infected when feeding on an infected person. Only Females spread the disease.