Dengue: How It Spreads, Warning Signs and Care

Dengue is a viral infection that can be caused by any of four related viruses. It is common in warm, wet parts of the world, and outbreaks are more frequent in rainy seasons. Although rare, it is found in some parts of the United States.

How it spreads

Dengue spreads through the bite of an infected mosquito. It does not pass directly from person to person, although a pregnant woman can pass it to her baby, and in rare cases it spreads through a blood transfusion, organ transplant or needle-stick injury.

Symptoms

About one in four people infected with dengue get sick, and illness can be mild or severe. Symptoms include:

• high fever;
• nausea and vomiting;
• rash; and
• aches and pains — pain behind the eyes, and in the muscles, joints or bones.

Symptoms usually last two to seven days.

Severe dengue

About 1 in 20 people who get sick develop severe dengue, which can cause shock, internal bleeding and death. It is more likely in people who have had dengue before, pregnant women and infants.

Warning signs usually start 24 to 48 hours after the fever goes away. Get medical care immediately for:

• severe belly pain or tenderness;
• vomiting at least 3 times in 24 hours;
• bleeding from the nose or gums;
• vomiting blood, or blood in the stool; or
• feeling tired, restless or irritable.

Diagnosis and treatment

A blood test can show whether someone has been infected. There is no specific medicine for dengue, and most people recover in about a week. If you think you may have it:

• see a health care provider and mention any recent travel;
• rest as much as possible;
• take acetaminophen for fever and pain, but not aspirin or ibuprofen; and
• drink plenty of fluids to prevent dehydration.

Severe dengue often requires hospital care.

Prevention

In the United States, a dengue vaccine is approved for children aged 9 to 16 who have had dengue before and live where it is common. Everyone can lower their risk by avoiding mosquito bites:

• use DEET or another EPA-registered insect repellent, following the label;
• wear clothes that cover arms, legs and feet; and
• close unscreened doors and windows.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Dengue" (summary from the Centers for Disease Control and Prevention): https://medlineplus.gov/dengue.html