Dengue and Dengue Fever
What is Dengue?
The major symptoms of dengue include fever, headache, muscle and joint pain and a typical skin rash that occurs all over the body, similar to measles. Rarely dengue 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 it Caused and Spread?Dengue is a serious infection especially among children; about two-fifths of the world’s population is at risk. Dengue and dengue haemorrhagic fever are spread from human-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 mosquito under the genus Aedes transmit dengue; especially the Aedes aegypti species is involved in spreading the infection and is considered as the main cause of dengue. This species of mosquito breeds in stagnant water and usually bites during daylight hours. The virus circulates in the blood for 2-7 days after the human is affected, during which the mosquito may acquire the virus by biting the infected human and spread it to another unsuspecting victim.
The symptoms typically develop anywhere between 2 to 4 days from the time of the mosquito bite and may last up to a week. The dengue virus doesn’t have any detrimental effect on the mosquito, that carries it, and the mosquito remains infected for life. Dengue is rarely spread through person-to-person contact. Usually the 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 resistant to that particular virus. However, they become much more susceptible to infection by other three serotypes.
Complications Involved with DengueDengue causes the dengue fever, which sometimes may 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 due to the disease are:
Low platelets, due to which clotting of blood doesn’t occur
Blood pressure may go dangerously low
Enlargement of liver and damage to it
Bradycardia (heart beating less than 60 counts per minute)
Damage to brain due to bleeding, seizures or encephalitis
Damage to the immune system
Diagnosis of DengueDiagnosis of dengue is considered when fever is accompanied by severe body 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 methods:
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
Decreased in platelet count also known as Thrombocytopenia occurs when platelets are found to be 100 000 cells or less and this may be due to disease condition
Increase in hematocrit i.e., the volume percentage of Red Blood Cells (RBS), by 20% should be a caution as it occurs due to rise in the vascular permeability of the plasma. Signs of plasma leakage appears as increased fluid accumulation in the chest and abdominal cavity known as pleural effusion or ascites respectively
Treatment for DengueThere 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 gets affected during dengue.
In the case of more severe forms of dengue, such as dengue hemorrhagic disease or dengue shock syndrome, it a must for the patient to be admitted to a hospital and given proper care. The mortality rate of a dengue patient without hospitalisation increases about 50 percent. Treatments such as intra-venous fluid replacements should be administered to these patients to prevent shock. Patients should drink plenty of fluids, as dehydration is prevalent among those affected with Dengue. Vaccines for all of the serotypes are being developed, which will be the most effective way to cure the disease.
Prevention of DengueAs there are no injections or vaccines available to cure dengue, prevention by following certain basic steps will be the most effective way to fight against the dreadful disease. Some of the ways to prevent the onset of dengue are stated as follows:
It is better to avoid stagnant water in flowerpots, buckets, barrels etc., in and around the house, as these are the favorite places for mosquitoes to lay eggs. Water should be stored in closed containers
Bleaching powder may be used in water sources that are not meant for drinking, as it prevents the development of mosquito eggs
The female mosquito feeds on blood as it requires the blood protein to produce eggs, hence it is better to use mosquito repellents, even when indoors
It is advised to reside in a well screened or air conditioned house. If not, mosquito nets may be attached to the windows
Usage of long-sleeved shirts, boots, socks and long pants is advised when outdoors
It is healthier to avoid being outdoors during dawn, dusk or early evenings when mosquitoes tend to roam around in the open
Mosquitoes are attracted to dark colored clothing hence it is better to wear bright and light colored clothes
Avoid strong perfumes, as mosquitoes are drawn towards strong body odours