Viral Hemorrhagic Fevers

What are viral hemorrhagic fevers (VHFs)?

Viral hemorrhagic fevers (VHFs) are a group of viral infections that can cause uncontrolled bleeding. They spread in many ways, including through insect bites and contact with body fluids of infected people or animals.

The viruses in this group range in severity. Many of them cause mild illness. But all of them can damage your blood vessels and interfere with your blood’s ability to clot, leading to life-threatening complications.

Types of viral hemorrhagic fevers

Viral illnesses that can cause hemorrhagic fevers include:

• Ebola virus disease (EVD).
• Marburg virus disease (MVD).
• Hantavirus pulmonary syndrome.
• Dengue fever.
• Lassa fever.
• Yellow fever.
• Crimean-Congo hemorrhagic fever (CCHF).

Where are viral hemorrhagic fevers found?

Different VHFs spread in different parts of the world. Most are found in parts of:

• Africa (mostly West and Central Africa, plus Uganda).
• Central and South America.
• Asia.
• The Pacific Islands.

Only hantaviruses cause VHFs in the U.S., Canada and Europe. Hantaviruses are a subtype of bunyavirus. Various types cause hantavirus pulmonary syndrome (in the Americas) and hemorrhagic fever with renal syndrome (in Europe).

What are the symptoms of viral hemorrhagic fevers?

Symptoms of VHFs vary depending on the disease. Early in the illness, they often include:

• Fever.
• Body aches.
• Dizziness.
• Fatigue (extreme tiredness).
• Headache.
• Rash.

In severe cases, VHFs can also cause:

• Bleeding from your nose, eyes, gums or vagina.
• Severe vomiting or diarrhea.
• Vomiting blood.
• Bloody diarrhea.
• Chest, neck or stomach pain.
• Difficulty breathing.
• Extremely low blood pressure.
• Seizures.
• Coma.

What causes viral hemorrhagic fevers?

Experts don’t fully understand the ways that hemorrhagic fever viruses cause severe bleeding. There’s evidence that the viruses damage your blood vessels, causing them to leak. They can also interfere with blood clotting, meaning your body can’t stop bleeding when it should.

Which types of viruses cause VHF?

Several types of viruses can cause viral hemorrhagic fevers, including:

• Arenaviruses.
• Filoviruses.
• Bunyaviruses.
• Flaviviruses.

Not all species of these viruses cause hemorrhagic disease. For instance, Zika is caused by a flavivirus, but it doesn’t damage your blood vessels the way VHFs do.

How do viral hemorrhagic fevers spread?

The viruses that cause hemorrhagic fevers each spread in different ways. Some ways you can get infected include:

• Mosquito bites.
• Tick bites.
• Contact with body fluids (blood, pee, poop, saliva, breast milk, semen or vaginal fluids) of an infected person.
• Contact with body fluids of an infected animal, usually rodents, nonhuman primates (like monkeys or apes), livestock or fruit bats.

What are the risk factors for VHFs?

Risk factors for getting an infection with a hemorrhagic fever virus vary by the type of VHF. You might be at higher risk if you:

• Live in or travel to countries where a VHF spreads.
• Are in contact with animals that carry VHFs.
• Care for people infected with a VHF.

Many VHFs carry a high risk of severe illness and complications in pregnant women.

What are the complications of VHFs?

VHFs can cause life-threatening complications, including:

• Miscarriage, low birth weight or premature birth.
• Edema.
• Shock.
• Internal bleeding.

How are viral hemorrhagic fevers diagnosed?

Providers might suspect you have a VHF based on your symptoms and certain risk factors (like your travel history). They’ll also test samples of your body fluids for signs of viruses. To get samples and perform tests, they might do:

• Blood tests.
• Throat swab.
• Urinalysis.
• Lumbar puncture (spinal tap).

How are viral hemorrhagic fevers treated?

There’s no specific cure for viral hemorrhagic fever. But there are antiviral treatments for a few VHFs. Most of the time, healthcare providers treat you by managing your symptoms and keeping your condition stable. Treatments might include:

• Ribavirin.
• Inmazeb® and Ebanga™ (monoclonal antibody treatments approved for Ebola).
• Supplemental oxygen or mechanical ventilation.
• Intravenous (IV) fluids.
• Medications to manage symptoms, like pain or nausea.

Can VHFs be prevented?

You can take steps to reduce your risk of VHFs by:

• Getting vaccinated. Vaccines are available for yellow fever, dengue and Ebola. Each are only available in certain countries and under specific circumstances. Ask a healthcare provider or your local public health authority about getting vaccinated before traveling to areas where you could be at risk for VHFs.
• Avoiding bug bites. You can reduce your risk of mosquito and tick bites by covering yourself with protective clothing, using mosquito nets and wearing bug spray proven effective against mosquitos and ticks.
• Avoiding contact with rodents, bats and other animals who can carry VHFs.
• Avoiding direct contact with human blood and body fluids. Wear proper personal protective equipment (gloves, goggles, aprons and masks) if you’re caring for someone who could be infected with a hemorrhagic fever virus.

What can I expect if I have a viral hemorrhagic fever?

If you’re severely ill, your provider will treat you in the hospital to manage your symptoms and any complications. You might be isolated from others to prevent spreading the virus.

Can you recover from hemorrhagic fever?

Yes, you can recover from milder forms of hemorrhagic fevers. Lassa, dengue and yellow fever often cause mild symptoms, but severe forms can be deadly. Others, like Marburg and Ebola, are often fatal.

What is the mortality rate for hemorrhagic fevers?

The mortality (death) rate varies for hemorrhagic fevers, depending on the virus causing it. For instance, Marburg and Ebola are the deadliest hemorrhagic fevers, with average mortality rates higher than 40%. But only about 1% of people with Lassa or dengue fevers die from them.

When should I seek care?

If you live in or have recently visited an area that has VHFs (or you have other risk factors), contact your healthcare provider if you develop symptoms. They’ll give you recommendations on how to take care of yourself and if you need to seek additional treatment.

When should I go to the ER?

Go to the nearest emergency room right away — and let them know you might have a VHF — if you have severe symptoms, including:

• Chest, neck or stomach pain.
• Difficulty breathing.
• Severe vomiting or diarrhea.
• Seizures.
• Confusion.

What questions should I ask my doctor?

It might be helpful to ask a healthcare provider:

• How do I prevent spreading the virus?
• What are my treatment options?
• How do I take care of myself?
• How long will it take to feel better?
• What new or worsening symptoms should I look out for?
• When should I follow up with you?