| As a biological warfare agent, the primary threat is delivery
by aerosol release. |
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| Symptoms |
Incubation is 2 - 5 days and usually followed by an incapacitating
fever of similar duration.
Common symptoms are fever, muscle pain, and prostration. Physical
examination may reveal only conjunctival injection, mild low blood
pressure, flushing, and petechial hemorrhages. Full-blown symptoms
typically evolves to shock and generalized mucous membrane hemorrhaging,
and often is accompanied by evidence of pulmonary hematopoietic,
and neuralgic involvement. Retinitis is common.
A small number of infections will lead to a late encephalitis.
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How does it spread?
Feeding mosquito
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Rift Valley fever (RVF) is a mosquito-borne disease that occurs
in Africa. It can be transmitted through the air and fomites from
slaughtering infected animals.
Patients generally have significant quantities of virus in blood
and often other secretions so special caution must be used in
handling sharps, needles, etc. It can easily be spread in healthcare
settings.
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Diagnosis
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Blood and other specimens from patients with signs and symptoms
require lab analysis.
(Sewage, bulk blood, suctioned fluids, secretions, and excretions should be autoclaved, processed in a chemical toilet, or treated with a 5% chlorine solution for at least 5 minutes in bedpan or commode prior to flushing.)
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Treatment
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Supportive therapy may be for liver and kidney failure, as well
as replacement of coagulation factors.
The investigational antiviral drug ribavirin is available on a
case-by-case basis.
Specifics on treatment can be found here
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Vaccine
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An investigative inactivated vaccine is available on a compassionate
basis.
Both inactivated and live-attenuated Rift Valley fever vaccines
are currently under investigation.
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Mortality
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Mortality is roughly 50%. Should the patient die, there should
be minimal handling of the body, with sealing of the corpse in
leak-proof material for prompt burial or cremation.
Survivors may be left with long-term challenges such as blindness,
hearing loss, and other neuralgic and eye problems.
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Sources:
CDC; http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/rvf.htm
USAMRIID's Medical Management of Biological Casualties Handbood;
Fourth Edition February 2001; pages 9-10; http://usamriid.detrick.army.mil/education/bluebook/bluebook.pdf
Federation of American Scientists; http://www.fas.org/nuke/intro/bw/agent.htm
Virtual Naval Hospital: Treatment of Biological Warfare Agent
Casualties; http://www.vnh.org/FM8284/index.html
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