Dengue fever is one of the most common infectious diseases in tropical and subtropical regions. In Vietnam, it is generally known as "sốt xuất huyết" (hemorrhagic fever), with its most severe manifestation being dengue shock syndrome (DSS), caused by the Dengue virus (genus Flavivirus, family Flaviviridae). Understanding the disease, its symptoms, prevention, and treatment will help you better protect yourself and your family.
1. What is Dengue fever?
Dengue fever, or Dengue hemorrhagic fever (DHF), is an acute infectious disease caused by the Dengue virus, transmitted through the bite of an infected mosquito (Aedes mosquito). Mild dengue fever can cause high fever, rash, and muscle and joint pain. Meanwhile, severe Dengue fever can lead to serious bleeding, a sudden drop in blood pressure (shock), and a risk of death.
The disease occurs in urban, rural, and mountainous areas, but is concentrated mainly in densely populated areas with high urbanization. Vietnam is an endemic region, particularly in the southern and south-central provinces.
Seasonal distribution: The disease breaks out strongly during the rainy season, when average monthly temperatures are high. In the South, dengue fever occurs year-round, while in the North it is common from July to November.
Population distribution: Everyone living in an area with an active dengue outbreak is at risk of contracting the disease or of asymptomatic infection.
2. Symptoms
Many cases of dengue fever have no clear symptoms. Symptoms usually appear 4–7 days after being bitten by an infected mosquito.
Dengue fever typically causes a high fever (40°C) accompanied by at least two of the following symptoms:
Headache
Muscle, bone, and joint pain
Nausea, vomiting
Pain behind the eyes
Swollen lymph nodes
Rash
Most cases of Dengue fever recover after about a week or longer. However, in some cases, the disease can progress to a severe form, posing a potential life-threatening risk. When blood vessels are damaged and platelet counts drop, patients may experience serious complications such as Dengue fever with warning signs, severe Dengue fever, or Dengue shock.
Some signs and symptoms that may indicate Dengue fever is progressing to a stage with warning signs or to a severe, potentially life-threatening form include:
Severe abdominal pain
Persistent vomiting
Bleeding gums, nosebleeds
Bruising or purpura under the skin
Difficulty breathing, rapid breathing
Cold, clammy skin
Lethargy, fatigue
Restlessness, agitation
3. Causative agent
The Dengue virus that causes Dengue fever/DHF belongs to the genus Flavivirus, family Flaviviridae, and includes 4 serotypes: D1, D2, D3, D4, all of which can occur in Vietnam.
After recovering from Dengue fever, the body only develops immunity to the specific serotype it was infected with, not to all 4 types (D1, D2, D3, D4). The risk of severe Dengue fever increases with a second, third, or fourth infection.
In severe cases, Dengue fever can damage the lungs, liver, and heart. Blood pressure can drop to dangerous levels, causing shock and even death.
4. Preventing Dengue fever
In Vietnam, the dengue vaccine approved by the Ministry of Health for use is the Qdenga vaccine (Germany), indicated for children aged 4 and above and adults, with a 2-dose schedule given 3 months apart. The first dose is given at the start, and the second dose is given 3 months after the first.
The World Health Organization (WHO) recommends that the vaccine is not the optimal method of disease prevention, especially in areas with high infection rates. Mosquito control and prevention of mosquito bites remain the most important measures. Therefore, if you are living in or traveling to an area with an active Dengue outbreak, the best way to prevent Dengue fever is to avoid mosquito bites:
Wear "protective" clothing when entering areas with many mosquitoes.
Use mosquito repellent containing Permethrin.
Improve and clean your living environment. At least once a week, empty and clean water containers, and cover water storage containers between cleanings.
5. Diagnosis
Dengue fever can be difficult to diagnose, as its signs and symptoms are easily confused with other diseases such as malaria, leptospirosis, and typhoid fever. Some tests used to diagnose Dengue fever include: Dengue virus isolation; serological testing to detect IgM using MAC-ELISA, IgG using GAC-ELISA, or the hemagglutination inhibition (HI) test; and testing for Dengue virus RNA markers using PCR (Dengue NS1Ag).
6. Treatment
There is currently no specific treatment for Dengue fever. Patients need to drink plenty of water to avoid dehydration from high fever and vomiting. During recovery from Dengue fever, if signs and symptoms of dehydration or warning signs appear, go immediately to the nearest medical facility:
Decreased urination
Little or no tears
Dry lips, dry mouth
Lethargy, confusion
Cold hands and feet
Paracetamol can help relieve pain and reduce fever. Avoid pain relievers that can increase the risk of bleeding complications, such as: aspirin, ibuprofen, and naproxen sodium. In cases of severe Dengue fever, you may need:
Supportive care in a hospital
Fluid and electrolyte replacement
Blood pressure monitoring
Blood transfusion to replace lost blood
7. Preparing before your appointment
If you suspect you have Dengue fever, you can contact a specialist or visit the nearest medical facility. Below is some information you should prepare before your appointment:
Write down any symptoms you are experiencing.
List your recent travel history, including dates.
List any medications, vitamins, or supplements you regularly take.
Dengue fever can progress quickly and cause dangerous complications if not detected and treated promptly. Proactive prevention, early recognition of symptoms, and timely medical examination will help protect the health of yourself and your family. At HIU Hospital, an experienced team of doctors and a modern equipment system are always ready to support, advise, and provide timely treatment, helping patients feel at ease throughout their healthcare journey.