Viral hemorrhagic fevers are infectious diseases  where the blood's ability to clot is affected. These diseases can also damage the walls of the tiny blood vessels, making them leaky. As a result there is internal bleeding that results into relatively minor to sometimes life-threatening disorders.

Hemorrhagic fevers include: dengue, ebola, lassa, marburg and yellow fever. These diseases most commonly occur in tropical areas of the world.

Viral hemorrhagic fevers are spread by contact with infected animals, people or insects. There is no treatment can cure viral hemorrhagic fevers, and immunizations exist for only a few types. The best approach is prevention.


The symptoms of viral hemorrhagic fevers vary by disease. Initial symptoms may include:

  • High fever
  • Fatigue
  • Dizziness
  • Muscle, bone or joint aches
  • Weakness

The symptoms can become life-threatening. Some types of viral hemorrhagic fevers may cause bleeding, but people rarely die of blood loss. Bleeding may occur:

  • Under the skin
  • In internal organs
  • From the mouth, eyes or ears

Other symptoms of severe infections can include:

  • Shock
  • Nervous system malfunctions
  • Coma
  • Delirium
  • Kidney failure
  • Liver failure


The viruses that cause viral hemorrhagic fevers live naturally in a variety of animal and insect hosts, most commonly mosquitoes, ticks, rodents or bats.

They typically live in a specific geographic area, so each particular disease usually occurs only where that virus's host normally lives. Some viral hemorrhagic fevers can be transmitted from person to person.

Traveling to an area where a particular hemorrhagic fever is common may cause infection after returning home. Up to 21 days takes for symptoms to develop.

Several other factors can increase the risk even more, including:

  • Sharing needles to use intravenous drugs
  • Working with the sick
  • Slaughtering infected animals
  • Having unprotected sex
  • Working outdoors or in rat-infested buildings


Viral hemorrhagic fevers can damage the brain, eyes, heart, kidneys, liver, lungs and spleen. In some cases they can be fatal.


If you live in or travel to areas where viral hemorrhagic fevers are common, take precautions to protect yourself from infection. Get vaccinated: the yellow fever vaccine is generally considered safe and effective. Check with the relevant institutions about the status of the countries you are visiting.

Do your best to avoid mosquitoes and ticks, especially when traveling in areas where there are outbreaks of viral hemorrhagic fevers. Wear long pants and long-sleeved shirts or permethrin-coated clothing. Avoid unnecessary activities at dusk and dawn and apply mosquito repellent.