14/11/2025
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Epidemiology
Viral Hemorrhagic Fever
What are viral hemorrhagic fevers?
Viral hemorrhagic fevers are a group of illnesses caused by viruses. These viruses live, for the most part, in rodents (e.g., rats and mice) and arthropods (e.g., mosquitoes and ticks). Viral hemorrhagic fevers affect multiple systems of the body and tend to cause hemorrhaging (bleeding). Five distinct families of viruses cause hemorrhagic fevers: arenaviruses (such as Lassa fever virus), filoviruses (such as Ebola virus and Marburg virus), bunyaviruses (such as Crimean Congo hemorrhagic fever and Rift Valley fever), flaviviruses (such as yellow fever), and paramyxoviruses (such as the Nipah virus and Hendra virus).
Who gets viral hemorrhagic fever?
Anyone can get a viral hemorrhagic fever, but it generally occurs in people living in or visiting areas with infected rodents, bats, or arthropods. Occasionally, people in other areas become infected when an infected rodent or arthropod has left its native habitat and entered a new area.
How are viral hemorrhagic fevers spread?
Most people get viral hemorrhagic fever through exposure to an infected arthropod, rodent, bat, or other animal. Viruses associated with arthropods are spread when a mosquito or tick bites a human. Viruses associated with rodents are spread through direct contact with rodent urine or f***s; they are also spread when people breathe in particles from rodent urine or f***s that have gotten into the air (e.g., from sweeping dirt containing dried urine or f***s). Spread of viral hemorrhagic fever has also occurred when humans handle an infected animal. Some viral hemorrhagic fevers are spread from person to person through close contact with infected people or their blood or body fluids or from contact with objects contaminated with infected body fluids.
What are the symptoms of viral hemorrhagic fever?
Specific signs and symptoms vary by type of viral hemorrhagic fever, but initial symptoms often include fever, fatigue, dizziness, muscle aches, loss of strength, and exhaustion. Patients with severe cases of viral hemorrhagic fever often bleed under the skin, or from internal organs or body openings. Severely ill patients may also exhibit dehydration, shock, problems with the nervous system (such as coma and seizures), and death. Some types of viral hemorrhagic fever are associated with kidney failure.
How soon after exposure do symptoms appear?
Symptoms may appear anywhere from days to weeks after exposure, depending on the type of viral hemorrhagic fever.
How are viral hemorrhagic fevers diagnosed?
Viral hemorrhagic fevers are diagnosed through special laboratory tests conducted by the Centers for Disease Control and Prevention (CDC). Samples may be taken from the blood and various tissues. Testing is done only with prior consultation and would be coordinated through the Virginia Department of Health.
What is the treatment for viral hemorrhagic fever?
Patients receive supportive care for relief of symptoms. Certain antiviral medications have been effective in treating some patients with certain types of viral hemorrhagic fever.
Do people who have been in contact with someone with viral hemorrhagic fever need to be tested and treated?
Generally, people who have been in contact with someone with viral hemorrhagic fever will need to monitor their health closely for a period of time after their exposure. Public health officials will conduct an exposure risk assessment and provide more detailed information based on the nature of their exposure and the viral hemorrhagic fever of concern. Testing and treatment are usually not needed for people who remain healthy during their post-exposure monitoring period.
How can viral hemorrhagic fever be prevented?
The best way to prevent viral hemorrhagic fevers is to avoid contact with infected animals and arthropods. Person-to-person transmission can be reduced by avoiding close physical contact with infected people and their body fluids. Vaccines are available for some viral hemorrhagic fevers, including yellow fever, Argentine hemorrhagic fever, and Zaire ebolavirus. Infection control techniques include isolating infected people and wearing protective clothing.
Could viral hemorrhagic fevers be used for bioterrorism?
Yes. Many hemorrhagic fever viruses are considered possible bioterrorism agents because they are highly infectious, can be aerosolized (made airborne), and would cause serious illness in the target population.
How can I get more information about viral hemorrhagic fever?
If you have concerns about viral hemorrhagic fevers, contact your healthcare provider.
Call your local health department. You can find your local health department at vdh.virginia.gov/health-department-locator/.
Visit the CDC page on viral hemorrhagic fevers at cdc.gov/viral-hemorrhagic-fevers/about/index.html for more information.
For Healthcare Providers:
Viral Hemorrhagic Fevers: Overview for Health Care Providers. Two-page summary of: Organism, Reporting, Infectious Dose, Occurrence, Natural Reservoir, Route of Infection, Communicability, Case-fatality Rate, Risk Factors, Incubation Period, Clinical Manifestations, Differential Diagnosis, Laboratory Tests/Sample Collection, Treatment, and Vaccine
Viral Hemorrhagic Fevers: Guidance for Healthcare Providers. Key Medical and Public Health Interventions After Identification of a Suspected Case
Last Updated: July 2, 2025
