Dengue Fever – Symptoms and Causes

Overview

Dengue fever is a disease caused by mosquitoes in tropical and subtropical regions worldwide. This illness presents with high fever and symptoms similar to the flu in its mild form.

However, the severe version, dengue hemorrhagic fever, can lead to dangerous bleeding, shock, and potentially death.

Each year, millions of people contract dengue infections globally. The disease is most prevalent in Southeast Asia, western Pacific islands, Latin America, and Africa.

Recently, dengue has expanded to new territories, with localized outbreaks appearing in European countries and southern regions of the United States.

Scientists continue to develop vaccines against dengue fever. Currently, the most effective prevention methods in areas where dengue is common include:

• Avoiding mosquito bites
• Taking measures to reduce mosquito populations
• Using insect repellent
• Wearing protective clothing
• Eliminating standing water where mosquitoes breed

These preventive actions remain crucial until vaccines become widely available.

Signs and Symptoms

Dengue fever symptoms often look like the flu. They usually start 4-10 days after a bite from an infected mosquito.

Common dengue fever symptoms include:

• High fever (104°F/40°C)
• Headache
• Muscle, bone or joint pain
• Nausea
• Vomiting
• Pain behind the eyes
• Swollen glands
• Skin rash

Most patients get better within a week. However, some cases become more serious and potentially life-threatening. This serious form is called severe dengue, dengue hemorrhagic fever, or dengue shock syndrome.

Severe dengue happens when blood vessels become damaged and leaky. The number of platelets (cells that help blood clot) drops significantly. This can lead to shock, internal bleeding, organ failure, and possibly death.

When To Get Medical Help

Seek emergency medical care if you’ve recently visited an area where dengue occurs and develop any of these warning signs:

• Severe stomach pain
• Continuous vomiting
• Bleeding from gums or nose
• Blood in urine, stool, or vomit
• Bruise-like spots under the skin
• Breathing problems
• Unusual tiredness
• Irritability or restlessness

These warning signs typically appear within 1-2 days after your fever goes away and indicate a medical emergency.

Even if you only have mild symptoms like fever after traveling to a dengue-prone area, it’s still important to contact your doctor. Early treatment can help prevent complications and support recovery.

Causes

Dengue fever is triggered by four different dengue viruses. Unlike many other diseases, dengue doesn’t spread through person-to-person contact. The transmission happens exclusively through mosquito bites.

Two specific types of mosquitoes commonly found in and around homes serve as carriers for dengue viruses. The infection process works in a specific way:

1. A mosquito bites someone already infected with dengue.
2. The virus enters the mosquito’s system.
3. When that mosquito bites another person, the virus transfers to their bloodstream.
4. Infection develops in the newly bitten person.

After recovering from dengue fever, a person gains immunity, but only against the specific virus type that caused their illness. This limited immunity creates an important health risk – you can still get infected by the other three types of dengue viruses.

Important Health Note: If someone contracts dengue fever multiple times from different virus types, their risk of developing severe dengue fever increases with each subsequent infection.

Risk Factors

People who live in or visit tropical areas face a higher chance of getting dengue fever. These regions include:

• Southeast Asia
• Western Pacific islands
• Latin America
• Africa

The risk increases in these places because the mosquitoes that carry dengue are common there.

Having dengue fever once before makes you more likely to get a severe case if infected again. This happens because the body’s immune response to the second infection can sometimes be stronger than needed, causing worse symptoms.

Complications

Severe dengue fever can cause serious internal bleeding and damage to organs. Blood pressure might drop to dangerous levels, leading to shock. In some cases, this can be fatal.

Pregnant women with dengue can pass the virus to their babies during birth. Babies born to mothers who had dengue while pregnant face higher risks of:

• Pre-term birth
• Low birth weight
• Fetal distress

These complications make prompt medical attention essential for anyone showing symptoms of dengue fever, especially pregnant women and those with weakened immune systems.

How to Stop Dengue

Vaccines

Dengue vaccines might be available for people aged 6 to 60 years. These vaccines need two or three doses given over several months. They’re meant for people who live in areas where dengue is common and who have already had the disease at least once.

People in the continental United States can’t get these vaccines yet.

In 2019, health authorities approved a dengue vaccine for children and teens aged 9 to 16 who have had dengue before and who live in the U.S. territories where dengue is common.

Avoiding Mosquito Bites

Vaccines alone can’t stop dengue in places where the disease is common. The best ways to prevent dengue are still avoiding mosquito bites and controlling mosquito numbers.

If you live in or travel to areas with dengue, these tips can help you avoid mosquito bites:

• Stay in Protected Housing
  • Use air conditioning when possible
  • Make sure windows have good screens
  • Be extra careful from dawn to dusk when mosquitoes are most active
• Dress To Protect Yourself
  • Wear long-sleeved shirts and long pants
  • Cover your feet with socks and shoes when in risky areas
• Use Effective Repellents
  • Apply permethrin to clothes, shoes, and camping gear
  • Consider buying clothes that already have permethrin in them
  • Use skin repellents with at least 10% DEET
• Remove Mosquito Breeding Sites

  • Empty and clean containers with standing water weekly

  • Check these common breeding spots:
    • Used tires
    • Flower vases
    • Pet water dishes
    • Planting containers

  • Keep water containers covered between cleanings

The mosquitoes that spread dengue often live around homes and lay eggs in standing water. By following these steps, you can help protect yourself and reduce mosquito populations in your area.