Dengue: Meaning, Dengue Types, Symptoms & Risk Factors

Diseases spread through the transfer of bacteria and viruses commonly occurring in animals and insects. One such disease that can truly jeopardise your health is dengue. One of the most common infections to affect people’s health worldwide, dengue is found in more than 120 countries. The dengue disease outbreak is typically more prominent in tropical countries in South America, Western Pacific Islands, Africa, Southeast Asia and South Asia. Today, over half of the world’s population is at risk from dengue. However, of the total estimated 100-400 million dengue infections recorded worldwide, over 80% of infections are asymptomatic or mild and can be treated easily.

What Is Dengue Fever? An Overview of the Viral Disease

Dengue fever is a viral infection caused by mosquito bites. Major symptoms of dengue include high fever, muscle and joint pain, headaches, etc. The treatment for dengue is aimed at relieving these aforementioned symptoms. You can generally treat mild dengue symptoms at home with over-the-counter medication. However, when the symptoms get severe, you need to seek immediate medical care.

Caused by the mosquito-borne dengue virus (DENV), dengue infection is a single-stranded ribonucleic acid (RNA) virus. DENV is commonly found in tropical countries. Dengue is spread via female mosquitoes of the genus Aedes. Moreover, there are four strains or serotypes of the virus DENV-1, DENV-2, DENV-3 and DENV-4. Secondary infection from other serotypes can increase the risk of severe dengue. Dengue doesn’t spread from person to person. However, a pregnant woman can pass it to their foetus during pregnancy or at the time of birth.

Stages Of Dengue Fever

Per the World Health Organisation (WHO), the lifetime of dengue fever comprises three stages:
1. Febrile
The febrile stage lasts two to seven days after the infection and is accompanied by various symptoms like body aches, joint pain, eye pain, appetite loss, skin rashes, etc.
2. Critical
The fever starts to subside from the third to the seventh day. However, this also marks the start of the critical phase. You may experience extreme fatigue, rapid reduction of platelets, etc. Severe cases can cause internal bleeding.
3. Recovery
The recovery stage of dengue fever starts after the critical phase ends. Your appetite and bowel movement returns to its normal state. Skin rashes may also begin to reappear.

What Happens When You Contract Dengue Fever?

The dengue virus enters your body through the mosquito’s saliva and binds with the white blood cells (WBC). With the WBC, the dengue virus keeps reproducing. However, WBCs are a part of your body’s immune system, and they produce cytokines to help fend off the virus. When WBCs fight viruses, your body temperature rises, which leads to high fever and other flu-like symptoms.

Dengue infection can get severe when the virus multiplies significantly and affects your liver or bone marrow. Due to a phenomenon called capillary permeability, blood vessels start leaking into the body cavities. Now, your blood vessels have less blood in them, which lowers your body’s blood pressure, and when the blood pressure is low, your heart cannot pump sufficient blood supply to other vital organs.

As for the bone marrow, the virus affects the stromal cells responsible for suppressing excessive inflammation in the body. Upon infection, the stromal cells can no longer suppress inflammation efficiently causing the bone marrow to be dysfunctional. This condition, in turn, impacts the bone marrow’s platelet production capacity. Since platelets are essential for blood clotting, a reduced platelet count amplifies the risk of bleeding.

Types of Dengue fever & Associated Symptoms

Dengue symptoms can range from mild to life-threatening. Depending on the severity of the symptoms, dengue fever can be classified into three types. They include the following.

• Dengue fever Dengue fever is characterised by a high fever of 104°Fahrenheit or 40°Celcius. Other symptoms of the fever include:
• Headache
• Nausea
• Sharp pain behind the eyes
• Vomiting
• Rashes
• Muscle and joint pain
• Swollen glands

You can recover from dengue within a week or two with proper medication and diet.

Dengue Haemorrhagic Fever (DHF) You may develop DHF, a severe form of dengue fever that can be fatal. The reason why the virus reproduces massively, remains unclear. What’s surprising is that the onset of DHF begins when your fever begins to subside. The common symptoms of DHF include:

• Severe abdominal pain
• Sudden change in temperature
• Haemorrhagic manifestations
• Persistent vomiting
• Thrombocytopenia
• Increased vascular permeability

Dengue Shock Syndrome (DSS)
The symptoms of DSS are similar to that of DHF, with one additional symptom, i.e., circulatory failure due to fluctuating pulse pressure or hypotension. Patients diagnosed with dengue can develop DSS rapidly. Not treating the symptoms on time can cause severe complications and even death.
Note that symptoms usually start showing after four to 10 days of being infected by a dengue-infested mosquito. However, you may mistake the mild symptoms for flu. Therefore, it is best to get yourself checked. Many people may not even experience symptoms of the infection.

What Are The Risk Factors For Dengue Fever?

You are at a much greater risk of developing dengue fever or its associated complications if:
You Live in Tropical Areas The dengue virus is commonly found in tropical and subtropical regions across the world. Areas like Southeast Asia, Latin America, South Asia, Pacific Islands, Africa, etc., are the top high-risk regions. If you live in these areas, you need to be extra cautious and take all the necessary precautions.

You Were Infected With Dengue in the Past

After you recover from dengue fever, you gain lifelong immunity to the serotype that caused the symptoms but not the other three. This means you can get infected by any of the other three serotypes in the future. Moreover, your risk of DHF and DSS also increases.

You can easily mistake the symptoms of dengue fever for a viral fever. However, it is always best to stay safe and get yourself tested for dengue. Your doctor may prescribe the following tests.

• Antigen Test Also known as the NS1 test, this antigen test is a suggestive diagnosis of dengue fever. The NS1 tests detect the non-structural protein (NS1) of DENV. The tests use synthetic antibodies to detect the dengue NS1 protein in the first seven days of the appearance of the symptoms.
• IgM Test This test detects Immunoglobin M (IgM) in the blood and lymph fluid that appear during the acute infection stage. These antibodies are detectable from four to five days after the onset of dengue symptoms. IgM tests can also tell you whether the infection was a first-time occurrence or a secondary infection due to other serotypes.
• IgG Test Immunoglobin G (IgG) test is similar to an IgM test. However, the IgG test helps detect infection in the later stages of the disease since that’s when the IgG antibodies are high in number. The antibodies are detectable from day six to day 10.
• RT-PCR Short for real-time reverse transcriptase-polymerase chain reaction, RT-PCR is a type of nucleic acid test that detects the RNA of the dengue virus. A positive test helps in detecting the virus early on and identifies the infection-causing serotype.

What Is The Treatment For Dengue Fever?

Currently, the only treatment for dengue fever is relieving the symptoms. Your doctor will prescribe medication and ways you can manage the symptoms. Here’s what you need to do.

• Stay Hydrated Water loss during vomiting, diarrhoea, nausea, fever etc., during dengue, can cause dehydration. If you don’t rehydrate yourself, it can impact your health significantly. WHO recommends five or more glasses of daily oral fluid intake. Intravenous (IV) fluid or electrolyte replacement can also be beneficial.
• Monitor Your Blood Pressure Drop in blood pressure is a severe symptom of dengue disease. Therefore, it is crucial that you monitor your blood pressure twice every day. You can get a home blood pressure monitor. Empty your bladder and rest for five minutes before measuring the pressure. Another important tip is to measure at the same time every day.
• Take Medicines to Control or Reduce Your Fever Your doctor may prescribe antipyretic drugs such as paracetamol to help you reduce the fever. Such medicines can also lower your body pain. Ensure you do not take painkillers like ibuprofen or aspirin, as they can cause bleeding. A cold-water sponge bath can help alleviate the fever.
• Consume Immunity-boosting Foods You need to replenish your immunity as it gets compromised when the dengue virus enters the body. Foods rich in vitamin C, like oranges, papaya, pineapple, etc., can help with digestion and reduce bloating. You must also consume protein-rich foods like meat and legumes to maintain the platelet levels in your blood.

How To Prevent Dengue Fever?

As of now, the only way to prevent dengue is to avoid contact with mosquito-related infections. The following are tips that can assist with dengue prevention.

• Use mosquito repellent creams, patch stickers, rollers, etc. up to three times a day. These products can be potent so ensure you do a patch test before application.
• Wear protective clothing, especially at night, as the mosquitoes’ thermal and odour receptors are highly efficient in the evening and night.
• Avoid places that are breeding grounds for mosquitoes, such as stagnant pools of bucket water, unclean floors, unwashed dishes, etc.
• Mosquitoes also breed in dark places. So ensure your house has sufficient sunlight. You can install mosquito screens.
• Keep yourself informed about dengue and its symptoms. Inform your family members about the precautions to take to avoid the infectious disease.