Dengue fever

Mosquitoes can spread a germ.

This germ causes a fever. It can also cause a rash. Your body might feel pain. You may feel sick to your stomach.

Most people feel better in a week. Some people get very sick. They may need to stay in a hospital. You can stay safe from bites. Wear long clothes to help.

Use spray to keep bugs away. It is good to be safe!

Dengue fever is a sickness caused by a virus.

Female mosquitoes spread the virus to people. The most common mosquito is called Aedes aegypti.

When a mosquito bites someone with the virus, it picks it up. The virus moves to the mosquito's spit. The next time the mosquito bites a person, it gives them the virus.

Symptoms usually start 3 to 14 days after a bite. Most people feel mild pain or a fever. They might also get a rash or a headache.

Many people feel better in a few days.

Some people get very sick. This is called severe dengue. In these cases, blood vessels can leak fluid. This makes blood pressure drop very low. This can be a medical emergency.

There are four different types of the virus. If you get one type, you are safe from it forever. But you can still get the other types. Getting a second type can make you much sicker. This is called antibody-dependent enhancement.

You can stay safe by avoiding mosquito bites. Use insect spray or wear long clothes.

Dengue fever is a sickness caused by a virus that lives in many tropical places.

It is a big concern for many countries around the world. Most people who catch it do not feel very sick at all. About 80% of people have only mild symptoms, like a fever. However, some people can get a much harder version called severe dengue. This can be a medical emergency because it affects the blood and organs.

Doctors call it a neglected tropical disease because it affects so many people in these regions.

The way the sickness spreads is through a very specific cycle.

It starts when a female mosquito from the Aedes genus bites an infected person. The virus moves into the mosquito and stays there for its whole life. The virus travels to the mosquito's salivary glands, which is where its spit is kept. When that mosquito bites a new person, it injects the virus into their skin. Inside the body, the virus moves to the lymph nodes and spreads through white blood cells. This process causes the body to react with fever and pain.

Humans first wrote about dengue outbreaks as far back as 1779. It took much longer to understand the real cause of the sickness. By the early 20th century, people finally understood how the virus worked and how it spread. Today, we know that the disease is spreading to new places like the southern United States. This is partly because of climate change, which helps mosquitoes live in new areas.

It is now found in more than one hundred different countries.

There are four different types of the virus, called serotypes. If you catch one type, you are safe from that specific type for your whole life. But you only have short-term protection against the other three types. If you get a second type later, it can cause a hard job for your body. This is called antibody-dependent enhancement, or ADE. In ADE, your body's own defenses actually help the new virus infect your cells more easily.

This makes the risk of severe illness much higher.

We can protect ourselves by making sure mosquitoes do not bite us.

You can wear long clothes or use insect repellent like DEET to stay safe. There are also vaccines that can help prevent the sickness. One vaccine called Dengvaxia became available in 2016 for people who already had the virus. A second vaccine named Qdenga became available in 2022 for children and adults. While there is no special medicine to cure the virus, doctors can help by giving fluids to patients. This helps keep the body strong while it fights the infection.

Dengue fever is a viral disease caused by the dengue virus (DENV).

It is classified as a neglected tropical disease because it affects many people in specific regions. The virus belongs to the Flavivirus genus, which includes other viruses like Zika and West Nile.

Most cases of dengue are either asymptomatic or manifest only mild symptoms. However, a small portion of patients develop severe dengue, which can be life-threatening. This disease is a major global health concern because it is spreading to new areas.

The infection process begins with the bite of an infected female mosquito.

Primarily, the Aedes aegypti mosquito spreads the virus to humans. When a mosquito bites an infected person, it ingests the virus during a blood meal. The virus then replicates in the mosquito's gut cells. It eventually moves to the mosquito's salivary glands. When that mosquito bites a new person, it injects infectious saliva into the skin. The virus then infects skin cells called keratinocytes and specialized immune cells called Langerhans cells. These cells carry the virus to the lymph nodes. From there, the virus spreads through white blood cells throughout the entire body.

An infection typically follows three distinct phases: the febrile, critical, and recovery phases. During the febrile phase, patients experience a high fever between 40 and 41 degrees Celsius. This phase usually lasts between two and seven days. It is often accompanied by headaches, muscle pains, and joint pains. The critical phase follows and is where severe dengue can develop. In this stage, plasma may leak from the blood vessels. This leakage can lead to fluid accumulation in the lungs or abdomen. Finally, the recovery phase lasts about two to three days. During recovery, patients may experience striking improvement but might also feel severe itching.

There are four confirmed serotypes of the dengue virus, known as DENV-1, DENV-2, DENV-3, and DENV-4. These types are distinguished by their antigenicity, or how the immune system recognizes them. If you are infected with one serotype, you gain lifelong immunity to that specific type. However, you only gain short-term immunity to the other three types. This creates a risk called antibody-dependent enhancement, or ADE.

In ADE, the antibodies from a previous infection do not neutralize the new virus. Instead, they help the new virus infect immune cells more easily. This process significantly increases the risk of developing severe complications during a second infection.

Human understanding of dengue has changed significantly over the centuries. The earliest descriptions of a dengue outbreak date back to 1779. For a long time, the specific cause of the sickness remained a mystery. It was not until the early 20th century that scientists understood the viral cause and how it spreads. Today, we see the disease moving beyond traditional tropical zones. It is now appearing in the Iberian Peninsula and the southern United States. Scientists attribute this expansion partly to the effects of climate change on mosquito habitats.

The scale of the dengue epidemic is massive. During 2023, more than 5 million infections were reported worldwide. This resulted in more than 5,000 documented deaths. Because many cases are mild or show no symptoms, the actual numbers are likely under-reported. Severe dengue is a medical emergency that can cause organ failure. It can also lead to a reduction in platelets, which are necessary for blood clotting. This reduction increases the risk of bleeding from the gums, nose, or even internally.

Medical professionals use several tools to manage and prevent the disease. There is no specific treatment to cure the virus itself. Instead, treatment is symptomatic, focusing on managing pain and providing fluids. In severe cases, patients require hospitalization for intravenous fluids to maintain blood pressure. Doctors use blood tests to detect viral RNA or specific antibodies to confirm a diagnosis.

Prevention relies heavily on mosquito control and avoiding bites. Vaccines are also available to help. Dengvaxia was approved in 2016 for those previously infected. The Qdenga vaccine became available in 2022 for children and adults.