Dengue fever

Other names for this disease are dengue fever, breakbone fever, and just dengue.

Introduction and Importance of Dengue Disease

Dengue fever was recognized in 2012 as the most significant viral disease transmitted by arthropods. It’s one of the major health issues in tropical and subtropical regions. It's also a top priority for the World Health Organization in terms of disease control and prevention. The need for blood transfusions in these patients severely depletes blood bank supplies. While the global burden of dengue fever isn’t fully understood, it’s concerning for both health systems and national economies. In Latin American and Caribbean countries, the disease burden is almost on par with meningitis, hepatitis, malaria, diphtheria, tetanus, whooping cough, polio, measles, and tuberculosis. In Southeast Asian countries, the burden from the disease is roughly comparable to meningitis, about twice that of hepatitis, and one-third that of AIDS. Among viral diseases transmitted by arthropods, it spreads the fastest.

 

Epidemiology:

The prevalence of this disease has increased 30-fold over the past 50 years. Every year, there are 50 to 100 million cases of dengue fever, with at least 500,000 of these patients being hospitalized, and about 2.5% of those hospitalized do not survive. Almost half of the world's population (around 2.5 billion people) is at risk of infection (as of 2012). This mosquito doesn't bite animals and prefers humans as its food source, which is why it spreads so rapidly. In recent years, this virus has become endemic in over 110 countries, while before 1970, the disease was only reported in 9 countries.

Reasons for the Increase in Dengue Fever

The main factor contributing to the rise in dengue fever is the growing urban population. This increase is particularly noticeable in Asia, especially in large cities with limited health and sanitation facilities.

The rise in international travel, with most travelers heading to countries where dengue is endemic, also plays a role.

Studies in Brazil and Cuba indicate that more virulent strains of the virus have spread widely.

 

The Cause of Dengue Fever

This disease is transmitted to humans by a mosquito known as Aedes aegypti. This mosquito usually bites during the day, especially in the early morning and just before dusk.

The virus is secreted in the saliva of the Aedes aegypti mosquito and infects a person after being bitten.

 

The Mode of Transmission

The virus is transmitted to humans through the bite of an infected mosquito. The bitten individual can pass the virus to uninfected mosquitoes 4 to 5 days (up to 12 days at most) after being bitten again by an infected mosquito.

The infected mosquito can transmit the virus throughout its entire life.

Dengue outbreaks typically occur during the rainy and warm seasons.

Aedes mosquitoes thrive and multiply in urban households, mainly in poor and marginalized areas.

No method of transmission other than mosquito bites has been mentioned for spreading this virus, so there's no need for isolating these patients.

 

 

Important points to mention:

1- If someone with dengue donates blood, the recipient can contract dengue fever.
2- There’s a possibility of the virus being transmitted from mother to baby during childbirth.

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Symptoms and clinical signs:

Nearly 80% of those infected show no clinical manifestations (very mild fever).
The incubation period for the disease is 4 to 10 days.

 

Classification based on the severity of the disease:

• Dengue without warning signs
• Dengue with warning signs
• Severe dengue

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Dengue without warning signs:
The patient's history should indicate residence or travel to an area where dengue is endemic.

 

Presence of fever along with two of the following:

• Headache
• Muscle and joint pain
• Pain behind the eyes
• Loss of appetite
• Nausea
• Vomiting
• Diarrhea
• Flushed skin
• Rash
• Laboratory tests (leukopenia with or without thrombocytopenia)

 

Dengue with warning signs:
The patient's history should indicate residence or travel to an area where dengue is endemic.

 

Presence of fever lasting 2 to 7 days along with one of the following:

• Abdominal pain or tenderness
• Persistent vomiting
• Clinical signs of fluid accumulation
• Mucosal bleeding
• Restlessness
• Enlarged liver
• Laboratory tests (increased hematocrit and/or decreased platelet count)

 

Dengue Fever:

In the patient's history, note whether they have lived in or traveled to an area where dengue is common.

 

A fever lasting from 2 to 7 days, accompanied by one of the warning signs or one of the following symptoms:

• Severe bleeding
• Severe dysfunction of organs (liver, central nervous system, heart, kidneys)
• Severe plasma leakage (leading to shock and fluid accumulation around the lungs or in the abdominal cavity)

• Dengue patients are classified into three groups: A, B, and C. Group A patients are sent home to recover. Group B patients are referred to the hospital for specific treatment. However, Group C patients need to be transferred to the hospital immediately for emergency care.

 

In Group A:

• Patients can drink fluids orally.
• Their urine output has not decreased.
• If they have a mild fever, they can take acetaminophen.
• They are advised to rest and stay hydrated at home.
• They should not take aspirin or ibuprofen (due to increased bleeding risk).
• They are monitored daily for potential disease progression.

 

In Groups B and C:

• Patients are referred to the hospital for medical care. Group B requires general hospital care, while Group C needs emergency and specialized care.

 

Warning:

There is no known specific treatment for dengue fever (treatments are supportive).
No vaccine has been generally produced to prevent this disease yet (several vaccines are in the final stages of research).
A French vaccine (Dengvaxia) has been produced, which is only used in children who have previously had the disease (not widely used).
In 2023, a Japanese vaccine received initial approval for release from the European Union (has not yet been released).
There are rumors about a vaccine being developed by Mexico circulating online, but it remains just a rumor.
The Aedes mosquito has been spotted in the southern and eastern borders of Iran.

 

 

Prevention:

Make sure to use air conditioning.
Even inside the house, use mosquito repellent.
When going outside, wear long-sleeve shirts and long pants tucked into your socks.
Ensure that windows and doors are secure and hole-free. If there's no proper ventilation, definitely use mosquito nets.
To reduce mosquito populations, eliminate places where they breed. This includes containers or pots that collect rainwater. Regularly change the water in birdbaths and pet water dishes.
Position door and window screens to keep mosquitoes out.
Highly scented soaps and perfumes may attract mosquitoes, so avoid using strong fragrances.
Try not to be outside during dawn, dusk, and early evening.

 

Common habitats for Aedes mosquitoes:

Plant pots and saucers
Water storage tanks (domestic drinking water, birdbaths, etc.)
Plastic containers
Bottles
Tree hollows and construction holes
Boats

Stagnant water is one of the key factors contributing to mosquito breeding, so to reduce the risk of mosquito production in stagnant water, you can do the following:

Remove excess water from plant pot saucers.
Turn over watering cans and store them under cover to prevent water accumulation.
Level the soil in plant pots to avoid the formation of puddles.
Change the water in pots daily and clean them out.
When picnicking or setting up a tent, choose an area away from stagnant water.

Considering these points, if you travel to these areas or if someone in your house has dengue fever, stay alert to protect yourself and other family members from mosquitoes. Mosquitoes that bite infected individuals can transmit the infection to others in the house. If symptoms persist, make sure to visit a doctor.

 

 

 

References

National Guidelines for Dengue Disease Control
Vector-borne Diseases from the Aedes Mosquito (Human Care for Dengue Disease)
Practical Care Guidelines for Aedes aegypti and Aedes albopictus in Iran
Clinical Guidelines for the Diagnosis and Treatment of Aedes-transmitted Arboviral Diseases