There are four similar viruses that cause dengue:
DENV-1, 2, 3, and 4 are part of the flavivirus family, which includes yellow fever, the West Nile and Zika viruses, and many others. DENV is short for dengue virus.1
When an infected mosquito bites you it can inject the dengue virus into your body through its saliva.2 The virus can invade cells in your skin and trick them into helping the virus to reproduce.3
Skin cells that have been invaded send a message to your immune system to tell your body to defend itself. Your body produces white blood cells to fight the virus. This is called an immune response.
Normally white blood cells destroy a virus, but dengue is clever and gets inside the white blood cells, tricking them into making many more viruses that travel all round your body.3
Your body has to use special proteins to stop the virus. They help the body recognize the dengue-infected cells and help protect the uninfected cells.
But these proteins also cause many of dengue’s symptoms, like fever.3
In cases of severe dengue, your blood pressure can drop and your organs may stop working properly.4
Because there are four dengue viruses, it is possible to be infected more than once. Even if you’ve had dengue before, you can become infected with a different dengue virus type – and severe symptoms are more likely to be experienced with secondary dengue infections. Many people don’t realize this, and it’s one of the things that makes dengue a real, recurring problem that is on the increase.5
