Dengue fever is a major health concern worldwide. It is caused by the dengue virus prevalent in tropical and sub-tropical regions of the world. When a dengue-infested mosquito bites a person, that person contracts the dengue virus. As such, dengue is not a contagious disease in that it does not spread through touch, cough, or secretion. However, it is hard to differentiate the symptoms of dengue and viral fever. High fever, headache, joint pain, nausea, and vomiting are the common symptoms of dengue. Only when these symptoms get severe do you realise your diagnosis of the illness is not a common flu.
Currently, there is no specific treatment or cure that can rid your body of the dengue virus. If infected, you can relieve the dengue fever symptoms by monitoring and controlling them. You can recover from dengue fever within two to three weeks with proper medication and diet.
How Does Dengue Transmit?
The dengue virus has four strains, including DENV-1, DENV-2, DENV-3 and DENV-4. When a dengue-carrying mosquito bites an infected person, it can spread the virus to other humans by biting them. The dengue virus is transmitted by the female mosquitoes of the Aedus aegypti. These mosquitoes also spread other infections Zika fever, yellow fever and chikungunya.
The virus enters your body through the mosquito’s saliva, penetrating through your blood streams. Your white blood cells make antibodies to fight off the virus, which is why you develop high fever and other dengue symptoms.
Dengue Fever Symptoms
Out of an estimated 100-400 million infections annually, 80% of dengue fever infections are mild or asymptomatic. However, severe a dengue illness can lead to internal bleeding and organ damage. Depending on the level of severity, dengue fever can be classified into three types:
- Classic Dengue Fever
Also known as break bone fever, classic dengue fever is characterised by acute fever lasting for three to 14 days after being bitten by an Aedus aegypti. Infected patients, especially children who have not had a history of dengue, you may experience minimal to no symptoms. The following are the common dengue symptoms:
- High Fever Of 140°F/40°C: Your body temperature rises because your white blood cells rapidly produce antibodies to kill the dengue virus. A high fever indicates that your body’s immune system is compromised. By taking antipyretic drugs like paracetamol, you can lower the fever.
- Retro-Orbital Pain: Retro-orbital pain is the pain behind the eyes. The muscles in this region of your skull can get strained. You may experience pressure behind the eyes and blurred vision. Retro-orbital pain also causes light sensitivity.
- Myalgia: Myalgia is the mild swelling of your muscles that causes tenderness and pain. Myalgia occurs during the early phase of dengue infection and affects the back, hip, upper leg, upper arms and shoulder muscles.
- Myositis: Among the severe dengue symptoms is Myositis, the inflammation of the skeletal muscles. It is characterised by motor weakness in all limbs. You may find it challenging to move around the house. Myositis is common in children but is usually benign.
- Frontal Lobe Headache: You may experience mild to severe pain in your forehead. Dehydration due to dengue can be a cause of headaches. Proper sleep and diet can alleviate the symptoms.
- Appetite Loss: You may find it challenging to ingest even the simplest foods during dengue fever. The dengue virus can affect the blood vessels in the digestive system causing you to vomit frequently. Therefore, the fear of vomiting compels you to eat less and may sometimes lead to anorexia.
- Arthralgia: Stiffness in the joints is called arthralgia. The infectious disease typically causes joint pains. Arthralgia results from immune system dysfunction – a consequence of dengue infection and is usually a more distinct dengue symptom for adults.
- Low Peripheral Blood Parameters: Low white blood cell count (leucopenia), low blood platelet count (thrombocytopenia) and high ratio of red blood cells (RBCs) to the total volume of blood (haematocrit) are the prominent dengue symptoms.
- Haemorrhagic Manifestations: Haemorrhage is the bleeding from blood vessels or an abnormal flow of blood. Blood vessels can rupture underneath the skin barrier leading to conditions like purpura, petechiae, ecchymotic lesions, etc. These haemorrhages can look like tiny spots or bruises.
- Rash: Another dengue symptom, rash or dermatitis, is the inflammation of the skin. A dengue rash is characterised by red pinhead structures embedded in your skin. Rashes occur on your face, thorax, extremities, abdomen, etc., but may reappear during the recovery phase.
- Swollen Glands: Dengue infection can cause your lymph and lymph nodes, to swell. Swollen glands is another indication of your body fighting an infection. You may notice painful lumps under the chin, in the armpits, on the side of the neck or around the groin.
- Dengue Haemorrhagic Fever (DHF)
DHF is a severe and sometimes deadly form of dengue. If you’ve had dengue before or have other underlying conditions, you can be at risk of DHF. Mild haemorrhages are common in classic dengue fever and are generally harmless. However, with DHF, the bleeding becomes excessive and causes organ damage. The following are the severe dengue symptoms caused by a DHF infection.
- Thrombocytopenia: Dengue virus can affect the bone marrow’s platelet production ability. The debilitating decrease in platelet counts is known as thrombocytopenia. Platelets cause blood clotting and a low platelet count leads to bleeding.
- Increases Capillary Permeability (CP): CP is a feature of blood vessel walls that facilitate blood flow. With an infectious disease like dengue, the wall degenerates and causes blood leakage in body cavities. Excess leakage can cause dengue to become more severe.
- Mild to Severe Haemorrhage Besides mild haemorrhagic manifestations in classic dengue fever, DHF can cause severe manifestations such as vaginal bleeding, intracranial bleeding and vomiting blood clots.
- Plasma Leakage: Plasma is the protein-rich fluid in your blood and its leakage can cause decreased blood volume. A low blood volume leads to other complications like low blood supply to vital organs, low blood pressure and significant bleeding in the gastrointestinal tract.
- Dengue Shock Syndrome (DSS): The symptoms of classic dengue fever and DHF, along with circulatory failure, lead to DSS. It is the most severe and possibly fatal form of dengue. Symptoms typically include:
- Rapid but weak pulse
- Narrowing of the pulse pressure
- Clammy skin
- Cold extremities
- Severe abdominal pain
If you notice warning signs of DSS, you should administer immediate medical care. If untreated, a profound shock with an undetectable pulse can cause death within eight to 24 hours.
Are the dengue symptoms different in adults and children?
Dengue symptoms for adults and children manifest differently. Adults typically experience myalgia, retro-orbital pain, nausea, etc., while children may experience vomiting and mild skin petechiae.
Does continuous high fever indicate a dengue infection?
Yes, a continuous high fever is an early symptoms of dengue, which patients often mistake as general viral fever. A high body temperature can indicate the presence of the dengue virus. However, it is best to take tests like antigen, immunoglobin M and G, RT-PCR, etc., to confirm the presence of dengue fever and receive treatment accordingly.
How does a dengue infection differ from malaria?
Both dengue and malaria are mosquito-borne diseases. Moreover, the symptoms of dengue and malaria include high fever, nausea and weak muscles. However, retro-orbital pain, rashes and swollen glands are distinct to dengue.
How is dengue treated?
Currently there's no specific cure for dengue. Doctors prescribe medication and treatment courses to relieve the early symptoms of dengue.
Can I infect another person with dengue?
Dengue spreads through mosquito bites only. Besides a pregnant woman passing the disease before or during childbirth, there is no indication of dengue being contagious.
Are there any side effects of dengue after recovery?
Yes. Post dengue symptoms typically include hair fall, weak immunity, weight loss, muscle pain, etc.
I do not live in tropical or subtropical areas. Can I still get dengue?
While dengue fever is prominent in tropical and sub-tropical areas, there is no evidence that one cannot contact it in other regions. You could still contract the disease due to stagnant waters, mosquito bites, etc.
Can I get dengue again if I've had it in the past?
Yes, you can contract dengue again. In fact, you are at greater risk of contracting dengue than someone who hasn't. While body builds immunity against one type of DENV virus, you could be susceptible to its other strains.