Dengue fever

Dengue fever

Dengue fever is a mosquito-borne disease caused by the dengue virus. It is common in tropical and subtropical areas. Most people who get dengue fever either have no symptoms or only mild ones. Symptoms usually start 3 to 14 days after being infected and can include a high fever, headache, vomiting, muscle and joint pains, and a skin rash. People usually feel better in two to seven days.

In a small number of cases, dengue can become severe. This can cause bleeding and problems with blood pressure. Dengue is spread by female mosquitoes of the Aedes genus, especially Aedes aegypti.

There is no special medicine to cure dengue fever. Treatment focuses on helping with pain and keeping people hydrated. Getting enough fluids is very important. There are vaccines to help prevent dengue, but they work best in people who have already had the disease once.

Dengue fever has been known since 1779 and is now found in over one hundred countries. Because of climate change, it is moving into new areas, including parts of Europe and the southern United States.

Signs and symptoms

Most people who get dengue fever don’t feel very sick, or they only have small problems like a simple fever.

Symptoms usually start 3 to 14 days after a mosquito bite. Common signs include fever, headaches, muscle and joint pain, feeling sick, throwing up, swollen glands, and a rash.

The illness usually has three stages: a fever stage, a critical stage, and a recovery stage. The fever stage lasts a few days and includes high fever, pain, and headaches. Most people start to feel better in about a week.

Recovery usually takes a few more days, and people often feel much better quickly. It's important to watch for warning signs and get help if needed.

Cause

Virology

Main article: Dengue virus

Dengue virus is a tiny germ carried by mosquitoes. It belongs to a group of germs that also cause yellow fever, West Nile fever, and Zika. The virus has four different types, and each type can make people sick in similar ways.

Transmission

The dengue virus is spread mainly by certain mosquitoes, especially ones called Aedes aegypti. These mosquitoes like to bite people at dawn or dusk but can bite at any time. When an infected mosquito bites a person, it can pass the virus to them. The virus can also spread through infected blood or during organ donations, though this is less common.

Risk factors

Getting bitten by an infected mosquito is the main way people catch dengue. This is more likely in places where the disease is common, especially where there are many people, poor cleanliness, and standing water where mosquitoes breed. Wearing long clothes, using mosquito nets, and applying insect repellent can help prevent bites.

Having certain health conditions like asthma or diabetes can make dengue worse. Getting infected with one type of the virus gives protection from that type, but not others.

Diagnosis

Mild cases of dengue fever can look like other common diseases such as Influenza, measles, chikungunya, and zika. These diseases are often found in the same warm areas of the world and can even happen at the same time. If someone gets a fever after visiting tropical or subtropics areas, doctors might think about dengue fever.

There are some warning signs that the illness could become serious, like stomach pain, throwing up a lot, swelling, and feeling very tired. Blood tests can help confirm if someone has dengue fever. Special tests can find parts of the virus during the early days of the illness.

Prevention

Mosquito control

Main article: Mosquito control

Dengue fever is spread by mosquito bites. The risk is highest where dengue is common, especially in crowded areas with standing water where mosquitoes breed. You can lower your risk by wearing long sleeves and pants, using nets when you rest, and applying insect repellent like DEET. Treating clothes, nets, and tents with a special liquid called permethrin can also help.

Keeping your home safe includes using screens on doors and windows, using air conditioning, and cleaning out containers that can hold water, like buckets or flower pots.

The best way to control the main dengue mosquito is to remove places where it can lay eggs. This means getting rid of open water sources or adding special substances to stop the mosquitoes from growing. Community efforts, like clearing gutters and drains and keeping yards free of standing water, are very important.

Vaccine

Main article: Dengue vaccine

There are two vaccines that help protect against dengue. Dengvaxia became available in 2015 and works for people aged 6 to 45 years. It needs to be given three times, six months apart. However, it should only be given to people who have already had dengue before.

Qdenga was approved in late 2022 and can be given to children as young as four years old, even if they have never had dengue before. It is given in two doses, three months apart.

In 2025 and 2026, health programs in big cities were expanded to give more people the dengue vaccine.

Treatment

As of July 2024, there is no special medicine to treat dengue fever.

Most people with dengue fever feel only a little sick, and they get better in a few days without any special treatment. For mild fever or pain, acetaminophen (also called Tylenol) can be used. However, medicines like aspirin, ibuprofen (such as Advil or Motrin IB), and naproxen sodium (like Aleve) should not be used because they can make bleeding more likely.

For people who are a bit sicker but can still drink, go to the bathroom, and do not show warning signs, careful monitoring at home is advised. Supportive care, such as taking pain medicine, drinking fluids, and resting in bed, is recommended.

Severe dengue is a serious condition that needs immediate care at a hospital, sometimes in intensive care. Warning signs include dehydration, low platelets, and rising hematocrit. Treatment may involve fluids given through a vein and, if needed, transfusions with platelets or plasma.

Prognosis

Most people with dengue get better and don’t have any lasting issues. Severe cases can be serious, but with proper care, the chances of serious problems are very low. Younger children and older adults may face more challenges if they get very sick from dengue.

Epidemiology

See also: Dengue fever outbreaks

Dengue fever is found in over 100 countries, and cases appear on every continent except Antarctica. Areas like the Americas, Southeast Asia, and the Western Pacific are affected the most. It is hard to know exactly how many people get sick because many cases are mild and not noticed.

Dengue is mostly found in cities where a special type of mosquito, called Aedes aegypti, lives close to people and breeds in small pools of water. These mosquitoes prefer humans and like to live near homes. In rural areas, other mosquitoes can also spread the disease.

Climate change is helping dengue spread. Warmer weather makes mosquitoes live faster and breed more. This change lets dengue appear in new areas, including places that used to be too cold. To stop dengue, it is important to remove standing water, improve city planning, and work together across different areas like health and the environment.

History

The first known mention of a sickness that might have been dengue fever was in ancient China. It was called a "water poison" linked to flying insects.

The main mosquito that spreads dengue moved from Africa between the 1500s and 1800s because of trade and people moving around. There were reports of illnesses like dengue a long time ago in places like Jakarta, Cairo, and Philadelphia. Dengue likely stayed in many warm, busy cities during the 1800s and early 1900s, even if big outbreaks were rare. The disease spread more during and after World War II, partly because of war and growing cities in Southeast Asia. Severe forms of the disease were first noted in the Philippines in 1953 and later became a big cause of illness in children in that region.

In Central and South America, efforts to stop the disease-carrying mosquitoes stopped in the 1970s, and dengue returned in the 1980s, causing many outbreaks. Today, dengue continues to affect more people worldwide as the mosquitoes that carry it spread to new areas, partly because of climate change and urban growth.

Etymology

The word "dengue" came into English from West Indian Spanish. It came from an East African word meaning "cramp-like seizure." Early names for the disease included "break-bone fever" because of the severe muscle and joint pains it causes. The term "dengue fever" became common after 1828.

Research directions

Scientists are learning more about how dengue fever affects people and the mosquitoes that spread it. They are finding better ways to diagnose the disease so doctors can treat it quicker. Researchers are also working on new medicines to fight the virus.

In addition to the vaccines that are already available, many new vaccine options are being tested. Scientists are also making special lab tools to help understand how dengue impacts the body.

Society and culture

When there is an outbreak of dengue fever, more blood is needed, but fewer people can donate blood because they might have the virus. People who have had dengue cannot donate blood for at least six months.

Each year on June 15, many countries celebrate International Anti-Dengue Day. This idea started in 2010, with the first event in Jakarta, Indonesia, in 2011. Other events took place in Yangon, Myanmar, in 2012, and in Vietnam in 2013. The goal is to teach people about dengue and to get help to stop the disease. The Philippines has a dengue awareness month every June since 1998. India also marks a National Dengue Day each year on May 16.