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Viral Hemorrhagic Fever: Overview
for Health Care Providers
One page summary of:
Route of Infection, Communicability, Case fatality rate,
Incubation period, Clinical manifestations, Differential
Diagnosis, Clinical criteria for a suspect case, Laboratory
tests/Sample collection
Viral Hemorrhagic
Fever: Guidance for Health Care Providers
Key Medical and Public Health Interventions After Identification
of a Suspected Case
What is viral hemorrhagic fever?
Viral hemorrhagic fever is a disease caused by viruses that live,
for the most part, in rodents (e.g., rats and mice) and arthropods
(e.g., mosquitoes and ticks). There are four distinct viruses that
cause hemorrhagic fevers: arenaviruses, filoviruses, bunyaviruses,
and flaviviruses.
Who gets viral hemorrhagic fever?
Anyone can get viral hemorrhagic fever, but it generally occurs
in people living in or visiting areas with infected rodents or arthropods.
Viral hemorrhagic fevers are more common in Africa; however, infected
rodents and arthropods carry some of the viruses that cause viral
hemorrhagic fevers in many parts of the world, including North and
South America, Europe and Asia.
How is viral hemorrhagic fever spread?
Most people get viral hemorrhagic fever through exposure to an infected
rodent or arthropod. 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 feces; they
are also spread when people breathe in particles from rodent urine
or feces that have gotten into the air (e.g., from sweeping dirt
containing dried urine or feces). 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 body fluids (e.g., saliva, blood, urine, semen).
Could viral hemorrhagic fever 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 population. Some
countries are known to have used viral hemorrhagic fever viruses
in their biological warfare programs.
What are the symptoms of viral hemorrhagic
fever?
Specific 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, in internal organs
or from body openings. Patients may also have shock, problems with
the nervous system, coma, and seizures.
How soon after exposure do symptoms
appear?
Symptoms may appear anywhere from 2 to 21 days after exposure, depending
on the type of viral hemorrhagic fever.
How is it diagnosed?
Viral hemorrhagic fever is diagnosed through special laboratory
tests conducted by the U.S. Centers for Disease Control and Prevention.
Samples may be taken from the blood and various tissues. Testing
is done only with prior consultation.
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 (e.g., arenaviruses
and bunyaviruses).
How can viral hemorrhagic fever be prevented?
No vaccines exist for viral hemorrhagic fevers, except for yellow
fever. Yellow fever vaccine is recommended only for individuals
traveling to areas such as tropical South America and sub-Saharan
Africa. The best way to prevent viral hemorrhagic fevers is to avoid
contact with infected rodents and arthropods. Person-to-person transmission
can be reduced through proper infection control techniques, including
hand washing and proper use of masks, gowns, and gloves.