Viral Hemorrhagic Fevers

What are viral hemorrhagic fevers?

Viral hemorrhagic fevers (VHFs) are illnesses caused by several types of viruses. Some of these viruses cause mild illness. Many others lead to life-threatening diseases with no known cures. One of the best known of this group is the Ebola virus.

What causes viral hemorrhagic fevers?

These illnesses are caused by viruses from 4 groups:

  • Arenaviruses
  • Filoviruses
  • Bunyaviruses
  • Flaviviruses

The viruses share these features:

  • They are only found in the areas where the host species lives.
  • Their survival depends on an animal or insect host. This host is also called the natural reservoir.
  • People are not the natural reservoir for any of these viruses. People only become infected when coming into contact with an infected host. But people can pass on some of these viruses to other people.
  • For the most part, these illnesses have no cure or treatment.
  • Outbreaks of these diseases happen only every now and then. This makes it hard to predict when the next outbreak will happen.

Rodents such as rats and mice, and ticks and mosquitoes are the hosts for many of these viruses. But researchers do not know what the hosts are for viruses like Ebola and Marburg.

You can get infected by coming in contact with the urine, stool, or saliva of an infected rodent. Or you can get infected by a tick or mosquito bite. Viruses can also be spread if you crush an infected tick.

The viruses that cause these illnesses are found wherever their host species lives. For some species, this is a limited area. In other cases, a certain species may be found worldwide. One example is the common rat.

Sometimes the host is taken from its natural habitat. That can cause an outbreak in a new place. Or an infected person may travel outside the virus’s natural area and give the disease to another person. With more people traveling each year, new outbreaks are becoming a greater threat.

What are the symptoms of viral hemorrhagic fevers?

The symptoms vary by the specific disease. Each person may also have slightly different symptoms. Various organs in the body can be affected. Symptoms often include:

  • Fever
  • Fatigue
  • Dizziness
  • Muscle aches
  • Loss of strength
  • Exhaustion

People with severe cases often show signs of bleeding. This may be under the skin, in internal organs, or from body openings such as the mouth, eyes, or ears. But blood loss is rarely the cause of death. These people may also have:

  • Shock
  • Seizures
  • Nervous system failure
  • Coma
  • Delirium
  • Kidney failure

The symptoms may look like other health problems. Always see your health care provider for a diagnosis.

How are viral hemorrhagic fevers diagnosed?

Your health care provider will ask about your past health and travel history. You will also need a physical exam. Blood tests can also help in the diagnosis.

How are viral hemorrhagic fevers treated?

Generally there is no known cure or treatment for these diseases. People with these illnesses may get supportive treatment. An antiviral medicine may help some people with Lassa fever.

Can viral hemorrhagic fever diseases be prevented?

No vaccines are available to prevent these diseases. Two exceptions are for yellow fever and Argentine hemorrhagic fever. As a result, the focus is on staying away from the host species.

For rodents, that includes:

  • Controlling the number of rodents
  • Preventing them from entering or living in homes or workplaces
  • Learning about safe cleanup of their nests and droppings

For viruses spread by ticks or mosquitoes, prevention focuses on:

  • Controlling the number of mosquitoes and ticks throughout a community
  • Useing insect repellent, proper clothing, bed nets, window screens, and other insect barriers to avoid being bitten

Travelers should take precautions to prevent infection. These include:

  • Using insect repellent
  • Wearing long sleeves and pants
  • Using bed nets in areas where outbreaks are occurring
  • Avoiding contact with livestock in areas where outbreaks are occurring

Key points

  • Viral hemorrhagic fevers are illnesses caused by several groups of viruses. They can be mild or life-threatening. Many have no known cure.
  • These viruses live in animals, often in rodents. People can become infected if they come into contact with an infected animal or person. They may also get the disease if they are bitten by a mosquito or tick.
  • No cure or treatment is available for these illnesses.
  • Prevention includes avoiding insect bites and staying away from infected rodents.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.