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Heat Emergency in Boston
Mayor Wu announced a heat emergency in the City of Boston through Wednesday, July 17. Cooling centers will be open at 14 BCYF community centers Monday through Wednesday, from 9 a.m. - 5 p.m.
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Dengue Fever

This fact sheet answers frequently asked questions about dengue fever.

Dengue fever is an illness caused by a virus that spreads through the bite of infected mosquitos. It is common in tropical and subtropical areas such as the Caribbean, Central America, South America and parts of Southeast Asia and Africa. Cases in the U.S. are usually in the south. Cases in Boston are rare and are most common in people who have travelled to a high-risk area.

The basics

Who gets dengue fever?

Anyone can get dengue fever. It is most likely to occur in people who have recently traveled to affected areas. The disease is usually milder in children than adults.

How is dengue fever spread?

Dengue fever spreads through the bite of an infected mosquito. It cannot spread from one person to another.


What are the symptoms of dengue fever?

Dengue fever usually starts suddenly with a high fever, severe headache, pain behind the eyes and joint, bone pain, and muscle pain. A rash on the feet or legs usually appears 3 to 4 days after the start of the fever.

A more severe form of the illness, called dengue hemorrhagic fever (DHF), starts with a fever for 2 to 7 days followed by vomiting, difficulty breathing, and stomach pain. Easy bruising, bleeding of the nose or gums, and internal bleeding may also occur. If untreated, this illness can be very serious. 

How soon do symptoms occur?

Dengue fever occurs 3 to 14 days after a bite from an infected mosquito.

Can a person get dengue fever again?

There are 4 different types of dengue fever virus. You are only protected against the type that infected you. You will not have protection from other types. A person could get dengue fever 4 times.


How can I prevent dengue fever?

There is no vaccine for dengue fever. The best way to prevent dengue fever is to limit your exposure to mosquitoes and their breeding areas. Use mosquito repellent, mosquito netting, and wearing a long-sleeved shirt and pants when traveling to affected areas.

Mosquitoes that have dengue fever tend to live indoors and are often found in dark, cool places. The risk of bites by this type of mosquito is highest during the early morning, several hours after daybreak, and in the late afternoon several hours before sunset. Cover containers that collect water or empty water weekly to prevent mosquitoes from breeding.


What is the treatment for dengue fever?

There is no specific treatment for dengue fever. Those with dengue fever should get plenty of rest, drink plenty of fluids, and if they feel worse 24 after their fever goes away, they should see a healthcare provider. If a person thinks they have dengue fever, they can take medication such as acetaminophen (Tylenol®) for the pain but should avoid aspirin.

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