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Key Diagnostic Tests.

After an incubation period of a week (range 2-21 days) there is an abrupt onset of fever, general malaise, muscle and joint pain, sore throat, abdominal pain and diarrhea. Hemorrhage and frank bleeding are evident about three days after the onset of symptoms.

• Measurement of coagulation times
• Detection of antigens or antibody to the agent in the blood (serology) to detect anti-Ebola virus IgM or IgG
• Proteinuria (high levels of protein in the urine, or bloody urine in extreme cases)
• Elevated liver enzyme levels in blood.
• Detection of viral nucleic acid by PCR.

Symptoms and effects.

Onset of the disease is rapid with a blinding headache being the first symptom reported. The virus attacks the liver and exhausts the bloodstream of clotting factors. Clotting begins to occur in an uncontrolled manner and as a result of this, the small hemorrhages that occur as a consequence of wear and tear do not seal and as they occur, internal hemorrhage continues. There is bleeding from tissues where tissue damage is common, such as the stomach, intestine, and gums. This gives rise to bloody diarrhea and vomiting of blood (hematemesis). The eyes often appear bloodshot. The loss of blood and fluids leads to lethargy, multiple organ failure, shock and death within 2 weeks of the appearance of symptoms in > 90% of cases.

Medical and Physical Countermeasures.

Vaccination (Immunoprophylaxis)

A vaccine is not available

 Specific Therapy

Immune serum from survivors (convalescent serum) has been shown to be effective.

Supportive care

Minimize intrusive care to protect a weakened vascular bed. Attempt replacement therapy only in the case of severe hemorrhage. Fluid infusion to deal with dehydration is often counterproductive. Improving blood clotting by transfusions of platelets may be attempted.

Decontamination

The virus is killed by common disinfectants, including hypochlorite bleach and glutaraldehyde, and by heat and ultra-violet light.

Agent Properties and Potential Uses

Ebola virus infection is gruesome, has a high mortality rate (>70%) and is highly infective when spread by contact with body fluids from affected individuals. However, its rapid onset, poor transmissibility through air, and high lethality make it strongly self-limiting. Affected areas and individuals can be quarantined and contamination controlled by strict application of barrier nursing practices. Even in central Africa under poor conditions compared to Europe and North America, trained teams were able to bring the disease under the control using lots of bleach and careful disposal of contaminated materials. None of the strains known to infect humans is transmissible through the air. However, it may yet prove possible to stabilize it for aerosol dispersion.

The typical outbreak kills just about everyone in a very small area, usually an isolated village and then dissappears without trace.

Very little is known about the natural history of the agent, the native animal reservoir is known, but it is not known if it has an intermediate vector. Recently, it has been found that humans can carry the virus without showing symptoms, indicating that man may also be a reservoir.

The component of the virus responsible for the destruction of blood vessels has been identified as one of the surface proteins of the virus known as the spike glycoprotein. This opens the path to finding drugs that can prevent the massive hemorrhage

Terrorist Acquisition and Attempted Use.

• Aum Shinrikyo attempted to recover the virus during an expedition to Central Africa.

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