16th May is observed as National Dengue Prevention Day every year. The aim is to raise awareness about dengue and its preventive measures.
Mosquitoes are known to cause serious illnesses and dengue is one such common condition that needs attention. Every year, our country struggles with dengue, with a huge number of people getting infected and some even get hospitalized. Dengue is an extremely common viral infection which is transmitted by mosquitoes and presents as high-grade fever, body aches, and pain in the joints. But knowing about its symptoms and prevention measures, one can easily fight this deadly infection.
So on this National Dengue Prevention Day, we answer some of the basic questions on dengue fever that everyone needs to be aware of.
What Is A Dengue Fever?
Dengue is a viral infection caused by the bite of female Aedes Aegypti mosquito. There are four serotypes (different types within a species of virus) of dengue virus. Infection with any one of the serotypes confers lifelong immunity from that particular strain but only partial protection against the others. At present, type 1 and type 2 strains are widespread in India.
It is possible to get dengue more than once. There are 4 different but related strains of the dengue virus. Being affected by one strain offers no protection against the others.
How Does Dengue Spread?
Dengue fever is spread by Aedes Aegypti mosquito that breeds in stagnant water. The mosquito that causes dengue can be identified by characteristic black and white markings over its body. Usually, it bites on the legs and arms and is most commonly seen during the daytime.
Is Dengue Infectious?
Dengue fever does not spread by touch, cough or secretions. But the spread of dengue from a patient to others is possible through a mosquito bite. The patient should be protected from contact with the mosquito by ensuring he sleeps under a bed-net and prevents the entry of mosquitoes into his/her house.
What Are The Symptoms Of Dengue?
Dengue fever should be suspected if you have a sudden onset of high-grade fever with
– Severe headache
– Pain behind the eyes
– Abdominal pain
– Body aches
– Skin rash
The fever can last for 5-7 days & usually decreases around the 3rd to 7th day of illness. This is followed by marked fatigue which can last for a few days to weeks. This marks the beginning of the critical phase where there could be a rapid decrease in the platelet count.
What Is Dengue Hemorrhagic Fever?
In rare cases, a more severe life-threatening disease called dengue hemorrhagic fever can also occur. It results in bleeding due to blood plasma leakage and in rare cases can cause dengue shock syndrome.
The World Health Organization has laid down criteria for a diagnosis of dengue hemorrhagic fever. These are
Low platelet count (<1 lac)
Fever for 2 to 7 days
It is important to monitor the platelet count and watchful of danger signs (bleeding, rash, abdominal pain or vomiting), which usually lasts for 2-3 days.
What Are The Various Tests Available To Diagnose Dengue Fever?
The diagnosis is usually established when there is sudden high fever accompanied by a severe body, muscle or joint pain. In the lab, it can be established by the following methods:
Antibody Detection And Serology: Dengue IgM and IgG antibody tests are usually done by ELISA. This test is usually positive after 5 to 7 days of illness.
Non-Structural Protein (NS 1) Antigen Or Dengue NS1 Antigen – High concentration of NS1 antigen is found in the blood of dengue-infected patients in the early phase. The sensitivity drops from day 4 to 5 of illness and usually becomes undetectable in the recovery phase.
Dengue Virus Isolation: It is the definitive test for dengue infection. It is useful only in the early phase when blood is collected before day 5 of illness. But, the disadvantage is that it is expensive and time-consuming and has a poor yield as compared to the molecular tests.
PCR: It helps in the early diagnosis of dengue infection (< 5 days of illness). Sensitivity is 100% in the first 5 days of illness but the PCR test is also expensive and time-consuming.
Complete Blood Count: A decreased platelet count may also occur in dengue fever (normal level is between 1.5 to 4 lacs). Therefore, platelet count should be monitored carefully and regularly especially when the fever comes down. An increased hematocrit i,e. The volume percentage of red blood cells can also occur in some cases by approximately 20%.
Typically, a patient will be positive for dengue-specific antigen, a decrease in platelet count and a decrease in total white blood cells (WBC) count.
How Is Dengue Treated?
There is no specific treatment method for dengue. Instead, the treatment is aimed at relieving the symptoms. For example, fever can be treated with antipyretic drugs like paracetamol to bring down the temperature and also relieve body aches.
Drugs such as aspirin and ibuprofen should be avoided as they may increase the risk of hemorrhage. Antibiotics are not required.
Most patients with dengue fever have mild illness and will not require hospitalization and can be treated at home by following strict dietary guidelines and course of medication. However, at times, it may cause a potentially serious complication, called severe dengue.
How Should Dengue Be Managed At Home?
People suffering from dengue fever should take adequate rest, eat a healthy diet and monitor their platelet count closely. Patients should drink lots of fluids (3-4 liters) to prevent dehydration, which is a common symptom in dengue.
Few home remedies like papaya leaves and kiwi are also quite popular in the treatment of dengue fever as they have been known to increase the platelet count. However, there is no research study to prove their efficacy in increasing the platelet count.
It is important to be watchful of any danger signs (bleeding, rash, abdominal pain or vomiting). One must follow up with their doctor on a regular basis and get immediate medical help in case of any health complications.
When Does A Patient Need To Be Hospitalized?
The patient is usually admitted if he is dehydrated, bleeding or shows any danger signs that require hospitalization. The patient is generally not admitted if the platelet count is above 50,000. The platelet transfusion is generally given if the platelet count is less than 10,000 in absence of bleeding manifestations.
Is There Any Vaccine Against Dengue?
The world’s first dengue vaccine won clearance in Mexico in December 2015. The vaccine has been approved for patients aged 9-45 years and can thwart all four subtypes of the dengue virus. The vaccine has an efficacy of 60%, which is low in comparison to other common vaccines administered for various illnesses (general vaccine efficacy should be around 80-90%). The protection period and cost of the vaccine are other important factors that need to be looked at before recommending it for public use.
While India is one of the countries that are hit severely by dengue fever, we still have a long wait before we get easy access to this new vaccine. Indian regulators will likely be looking closely at how well the dengue vaccine works in Mexico and wait for formal guidance from the World Health Organization.
A Quick Checklist To Help YOU Out!
-Ensure that the patient takes 3-4 liters of fluids (water, juice, tea, milk or soup) a day
-Keep a close watch on signs of dehydration. Check the patient’s tongue and urine output.
-The tongue should appear moist and pink in color. The patient should pass adequate urine (every 3 hours)
-If the patient can’t take enough fluids orally and his urine output is less, he/she should be admitted to a hospital for intravenous fluids
-The blood tests should be started when the fever starts
-In the early stages, the platelet count is usually within normal range but hemoglobin level may be high
-If the hemoglobin level is raised ( >14g/dL), a doctor should be consulted even if the platelet count is in the normal range
-The platelet count begins to fall once the fever starts to come down
-Remember that even when the platelet count is falling, there is no need to panic. Talk to your doctor to know if you need to be hospitalized or any other precautions have to be taken.
-There is no role of platelet transfusions in a patient who has no active bleeding. Do not insist the doctor for platelet transfusion in the absence of bleeding because your doctor knows the best treatment suitable for you based on your condition.
Take precautions to prevent mosquitoes from breeding in and around your homes. If anyone in your family develops a sudden, high-grade fever with body aches and joint pains, please consult a doctor for early detection and proper management of dengue fever.
Stay Healthy, Stay Happy!
(The article is reviewed by Dr. Swati Mishra, Medical Editor)
Dengue. Questions and Answers. The World Health Organization (WHO). https://www.who.int/immunization/research/development/dengue_q_and_a/en/