Dengue Fever - Causes, Symptoms, Precautions, Prevention, and Identifying Aedes Mosquitoes

Dengue Fever - Causes, Symptoms, Precautions, Prevention, and Identifying Aedes Mosquitoes

Key Facts about Dengue Hemorrhagic Fever

Dengue hemorrhagic fever is a disease that spreads during the rainy season and affects both children and adults. It is caused by a virus transmitted by Aedes mosquitoes. When an infected mosquito bites a person, the virus is transmitted, causing symptoms. Severe cases can lead to shock, and if not treated properly and promptly, may result in death due to bleeding complications.

It is a dangerous disease and a public health issue in tropical and subtropical regions, with Aedes mosquitoes acting as vectors. Raising awareness about the importance of the disease and providing accurate information and understanding helps patients who suspect they have dengue hemorrhagic fever and their caregivers to recognize the proper initial home care methods, dangerous signs requiring urgent medical attention, and ways to prevent the disease.

According to the disease surveillance reporting system 506 by the Bureau of Epidemiology, the dengue hemorrhagic fever situation in 2016, as of December 20, 2016, showed a cumulative total of 60,964 cases, with an incidence rate of 93.18 per 100,000 people. The number of cases decreased by 57.36% compared to the same period in 2015. There were 60 deaths, with a fatality rate of 0.10%. People have become more cautious and proactive in preventing the disease spread by Aedes mosquitoes, but close monitoring is still necessary since there is no specific treatment for dengue hemorrhagic fever, and it can be fatal if proper primary care is not provided.

Causes

The disease is caused by the dengue virus, which has four types: dengue-1, dengue-2, dengue-3, and dengue-4. This means that a person can contract dengue hemorrhagic fever multiple times. The primary vector for the disease is Aedes mosquitoes. When an Aedes mosquito carrying the dengue virus bites a person, the virus is transmitted, leading to infection. Aedes mosquitoes typically feed during the day and lay their eggs in clean, stagnant water.

Symptoms

The disease progresses in three stages: fever, critical, and recovery. The main symptoms in the fever stage are:

1. Fever stage:

This stage is characterized by a high fever of around 39 - 40°C (102.2 - 104°F) that lasts for 2-7 days. Common symptoms include facial flushing, headache, eye pain, body aches, joint pain, nausea, vomiting, loss of appetite, abdominal pain, and possible bleeding. The symptoms of dengue hemorrhagic fever do not usually appear simultaneously, so it is important

2. Critical stage

When a patient exhibits any of these symptoms, such as fatigue, lethargy, refusal to drink water or eat, lack of normal activities, increased thirst when fever subsides (in some cases), vomiting, severe abdominal pain, abnormal bleeding, or signs of impending shock (cold and clammy hands and feet, excessive irritability in young children, cool body temperature, sweating, mottled skin, skin pallor, decreased urine output, or no urination for 4-6 hours), and changes in behavior such as confusion or babbling, they are in a dangerous stage of the disease. As the patient enters shock, they may remain conscious and coherent, but they must be rushed to the nearest hospital immediately. Encourage the patient to sip on electrolyte solution or fruit juice with a pinch of salt, taking small sips frequently. Drinking only plain water is not recommended.

Shock is usually caused by plasma leaking out of blood vessels, resulting in increased blood concentration. In some cases, this may lead to low blood pressure or shock. Additionally, shock may be caused by internal bleeding in vital organs such as the stomach, excessive menstrual bleeding, or bleeding from surgical wounds in patients who have undergone surgery. Shock can lead to multiple organ failure, particularly in the kidneys and liver, with severe consequences that may be fatal.

3. Recovery stage

When a patient has received treatment and is discharged from the hospital, care and precautions should be continued at home. For the first five days of the disease, prevent mosquito bites, as the virus remains in the patient's blood and can spread to others. If someone in the household develops a high fever, take them for a medical examination and closely monitor their symptoms. Be cautious of bleeding for another week. Avoid picking the nose, brushing teeth, or engaging in vigorous exercise or sports. If any abnormal symptoms appear, seek medical attention immediately. Paracetamol may be administered to reduce fever, but aspirin or NSAIDs such as ibuprofen should be avoided, as they can increase gastrointestinal bleeding or have adverse effects on the liver.

Treatment

Currently, there is no specific treatment for dengue fever, and only symptomatic treatment is available. Therefore, prevention and control measures, such as eliminating standing water containers within homes and ensuring they are tightly sealed, are important. Another method is the administration of dengue fever vaccines, which are now available in Thailand. The vaccine can be used for children aged 9 to 45 years and has been shown not only to prevent dengue fever but also to reduce the occurrence of severe dengue by up to 93.2% and reduce hospitalizations due to dengue by 80.8%.

• • • There is no antiviral medication; treatment is based on symptoms.
    • Sponge bath with plain water when feverish; sponge for 10-15 minutes.
    • Take paracetamol to reduce fever when necessary, spacing doses at least 4-6 hours apart. Avoid aspirin at all costs.
    • Drink plenty of fluids.
    • Eat soft, easily digestible foods. Avoid foods with red, black, or brown colors.
    • Monitor for any danger signs and consult a doctor as scheduled, especially if the patient is unable to resume normal activities or if their condition does not improve.

If a patient is discharged from the hospital, they should continue with the following care:

• • • Dengue patients should avoid being bitten by mosquitoes within the first 5 days of the illness because they still have the virus in their blood, which can be transmitted to others. If anyone in the household has a high fever, take them for a check-up.
    • Closely monitor the patient's symptoms. If there are any abnormal symptoms, seek medical attention immediately.
    • Administer paracetamol to reduce fever. Avoid aspirin or NSAIDs such as ibuprofen, as they can increase gastrointestinal bleeding or have adverse effects on the liver.
    • Eliminate mosquito breeding sites at home, work, and school.

Prevention

• • • Sleep inside mosquito nets or in rooms fitted with mosquito-proof screens.
    • Avoid playing in dark corners or areas without proper airflow.
    • Classrooms and workplaces should be well-lit with good ventilation and no mosquito breeding sites. For example, change the water in flower vases daily, and plant ferns in soil.
    • Eliminate mosquitoes in shaded areas within the house, closets, and around the house every week.
    • Remove standing water in containers and keep them tightly covered. If unable to cover, add Abate sand or introduce guppy fish. Add salt, lime juice, or detergent to saucers under furniture legs and plant pots once a week.
    • Dispose of or destroy unused materials around the house, such as cans, coconut shells, old tires, etc.

Dengue Vaccine

Currently, there is a 4-strain dengue vaccine (DEN 1-4) recommended for ages 9-45 years old. The vaccination schedule includes 3 shots (given at 0, 6, and 12 months) for those who have been previously infected. It is not recommended for those who have never been infected before.

From research in Asia-Pacific and Latin America among volunteers aged 9-16 years, it was found that the CYD-TDV vaccine has high efficacy in preventing dengue fever as follows:

• • • Protection against all dengue strains at 65%
    • Reduces hospitalizations by 80.8%
    • Prevents dengue virus infection by 92.9%

Those who cannot receive the dengue vaccine include:

• • • Individuals allergic or sensitive to any active ingredients or other components in the dengue vaccine.
    • Those who have experienced an allergic reaction after the first dose of the dengue vaccine, such as itching, rapid breathing, or swelling of the face and tongue.
    • People who are sick with any feverish illness, from mild to high fever or acute illness. In this case, the doctor will postpone the vaccination appointment until the patient fully recovers.
    • Those with immune system deficiencies, such as genetic disorders, HIV infection, or taking immunosuppressive drugs like Prednisone or an equivalent dose of 20 mg or 2 mg/kg body weight for at least 4 weeks.
    • Pregnant or breastfeeding women.

5 Steps to Control Mosquitoes and Prevent Dengue Fever

• • • Step 1: Tightly cover water storage containers.
    • Step 2: Change the water in various containers every 7 days to break the larvae breeding cycle.
    • Step 3: Release larvivorous fish into permanent water containers, such as lotus ponds.
    • Step 4: Improve the environment to allow proper airflow and prevent mosquitoes from resting.
    • Step 5: Regularly practice these 4 steps until they become habits.

If a patient has a high fever for more than 3 consecutive days, take them to a doctor for a proper diagnosis. Be cautious not to let mosquitoes bite during the daytime and eliminate mosquito breeding sites by tightly covering water storage containers, using mosquito nets, and applying mosquito repellent.

For more information, please contact the Pediatrics Department at 0-2561-1111 press 1.

Physician

Dr. Pranee Sitaposa

Pediatric Infectious Disease Specialist