Dengue and Dengue Fever
What is Dengue Fever?
What are the Symptoms of Dengue Fever?The major symptoms of dengue fever include sudden high fever (as high as 40 °C or 104 °F), chills, severe headache (usually behind the eyes), muscle ache and joint pain, nausea, vomiting, flushed skin and in some cases a skin rash similar to measles. Dengue fever symptoms may be mild initially and mistaken for a flu, cold or a viral infection. In rare cases dengue fever may develop into a more life threatening form known as dengue hemorrhagic fever, which results in bleeding, decreased blood platelet count or thrombocytopenia, blood plasma leakage or the more fatal dengue shock syndrome, which causes dangerously low blood pressure.
How is Dengue Fever Caused and Spread?Dengue fever and dengue hemorrhagic fever spread from human-to-mosquito-to-human by the bite of mosquitoes carrying the dengue virus. The dengue virus belongs to a group known as Flavivirus and can be typically divided into four viral serotypes, DEN-1, DEN-2, DEN-3, and DEN-4, which are closely related but differ in their antigens. Many species of mosquitoes under the genus Aedes transmit dengue; in particular the Aedes aegypti species is most commonly associated with it and the major cause of dengue transmission. This species of mosquito breeds in stagnant waters and usually bites during daylight hours. The virus circulates in the blood for 2-7 days after a person is infected, during which time a mosquito biting the person would acquire it and in turn bite and infect another person.
The symptoms typically develop anywhere between 3 to 14 days but usually start within 4 to 7 days of infection, and may last from 7 or 10 days. The dengue virus doesn’t have any detrimental effect on the mosquito that carries it, and the mosquito remains infected for life. Dengue disease is spread when a mosquito bites an infected person and becomes a carrier of the dengue virus. The mosquito then bites another healthy person and thus spreads the disease causing a possible epidemic breakout. A person infected with a single type of dengue virus serotype out of the four, develops resistance to only that particular virus. However, they become much more susceptible to infection by the other three serotypes.
Dengue Fever ComplicationsDengue fever may sometimes develop
into more dangerous forms such as dengue hemorrhagic fever or dengue shock
syndrome, which may lead to the development of life-threatening symptoms. Some
of the complications caused by the disease include:
Low platelets, due to which clotting of blood doesn’t occur
Blood pressure may go dangerously low
Enlargement of liver and liver damage
Bradycardia (heart beating less than 60 counts per minute)
Damage to the brain due to bleeding, seizures or encephalitis
Damage to the immune system
Dengue FeverDiagnosis of dengue is considered when sudden high fever is accompanied by
severe body, muscle or joint pain. It is important to be evaluated when a person develops fever
within two weeks of being in the tropics or sub-tropics. Dengue often causes
symptoms that are similar to other diseases such as flu, measles, and typhoid
fever etc. Hence investigations are always performed to exclude other disease
conditions. Usually the blood of the patient is tested for the presence of
antibodies and virus. Diagnosis of dengue infection can be done by the following
Isolating the virus by collecting serum sample from patients within 5 days of appearance of symptoms
Detection of specific antibodies can be done by collecting serum within 6 days after onset of symptoms. The serum is tested for specific anti-dengue antibodies by Enzyme-linked Immunosorbent assay (ELISA). Titres of IgM and IgG antibodies increase four-fold in serum sample
Using Polymerase Chain Reaction (PCR) for detecting viral genomic sequence from Serum or Cerebro Spinal Fluid (CSF) samples collected from the patient, which is more expensive and complicated
In the case of more serious complications such as dengue hemorrhagic fever, the following diagnosis must be performed:
A tourniquet test is to be conducted, where a tourniquet is tied to the arm and if blood blotches tend to appear beyond the tourniquet, the patient may be suffering from increased bleeding, which may indicate Dengue Hemorrhagic Fever
A decrease in platelet count, also known as Thrombocytopenia occurs when platelet count falls below 100,000. Normal platelet counts are between 150,000 to 400,000. A decreased platelet count may be due to dengue fever.
An increase in hematocrit i.e., the volume percentage of Red Blood Cells (RBS), by 20% could be another indicator as it occurs due to a rise in the vascular permeability of the plasma. Signs of plasma leakage appear as increased fluid accumulation in the chest and abdominal cavity known as pleural effusion or ascites respectively.
Dengue FeverThere are actually no known antiviral drugs or injections
available for the cure of dengue. However, the disease can be treated with
plenty of supportive care and treatment that would eventually help save the
patient’s life. Dengue is characterized by fever and intense body ache. The
fever can be treated with antipyretic drugs such as paracetamol and the body
ache can be treated with analgesics that help relieve the pain. Drugs such as
aspirin and ibuprofen should be avoided as they may increase the risk of
hemorrhage. The patient can also be treated with natural home remedies such as
papaya leaves, kiwi and other food items that have been proven to help in the
increase of platelet count, which becomes lower during
In the case of more severe forms of dengue, such as dengue hemorrhagic disease or dengue shock syndrome, the patient must be admitted to a hospital immediately and given proper care. The mortality rate of a dengue patient without hospitalisation is higher by about 50 percent. Treatments such as intravenous fluid replacement should be administered to these patients to prevent shock. Patients should drink plenty of fluids, as dehydration is common among those affected with Dengue. Vaccines for all of the serotypes of dengue are currently being developed, and may when finally available, be the most effective way to cure the disease.
Prevention of Dengue FeverAs there are no
injections or vaccines available to cure dengue, prevention by following certain
basic steps is really the most effective way to fight the disease. Since the only way to get dengue is from a mosquito bite, the best way to prevent it is to avoid mosquitoes and prevent mosquito bites. This is particularly important if a dengue epidemic is underway in your city or town. Some ways to prevent dengue are described below:
Mosquito breed in stagnant water. Hence it is advisable to avoid stagnant water and pools on the ground, in flowerpots, buckets, barrels etc., in and around the neighborhood and the house. Water should always be stored in closed containers. Stagnant pools of water on the floor should be mopped up.
Bleaching powder may be used in water sources that are not meant for drinking, as it will prevents the development of mosquito eggs.
Avoid being bitten my mosquitoes in the first place. Mosquitoes bite us as they require the protein present in human blood to produce eggs. To prevent being bitten, keep mosquitoes away by using mosquito repellents, whether indooors or outdoors.
To avoid mosquitoes it is best to live inside a well screened or air conditioned house. If this is not possible, mosquito nets should be attached to all windows.
Another way to prevent mosquito bites is to wear long-sleeved shirts, pants, socks, and shoes or boots when spending time outdoors.
Mosquitoes are more active at dawn, dusk or early evening. It is therefore advisable to avoid being outdoors during these times to decrease the chances of being bitten by a dengue carrying mosquito.
Mosquitoes are attracted to dark colored clothing - therefore it is better to wear bright and light colored clothes.
Avoid strong perfumes or scented body lotions, as mosquitoes are drawn to strong odours.