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Key Diagnostic Tests.

• Detection of antigens or antibody to the agent in the blood (serology) - an indirect immunofluorescence assay is available;
• ELISA for IgM and IgG is useful in the early stages of infection;
• PCR is available, but may be problematic in the US because of Four Corners or Sin Nombre virus.

The urine is the best source for detection of the virus.

Symptoms and effects.

The typical incubation period is 12-16 days (range 5-42 days). The disease begins with a toxic phase characterized by flu-like symptoms: fever, chills, frontal or retroorbital headaches, backaches and dizziness that is accompanied by diarrhea and proteinuria that lasts for 4-7 days. Patients often look bleary-eyed because of swelling of the eyelids and conjunctivitis. There is a leukocytosis and a thrombocytopenia that lead to the formation of petechiae (blood spots) on the buttocks and soft palate. This development of capillary leakage syndrome leads to a loss of blood pressure at about the fifth day. The drop may be small and short-lived or large enough to cause shock. The skin and extremities may also be warm and dry to the touch at this stage.

The disease enters a second phase affecting the kidneys characterized at first by oligouria (infrequent urination) then polyuria (frequent urination), hypertension, bleeding of the mucous membranes and edema of the lungs.

The fatality rate ranges from 1-3% for Puumala virus, 7% for Hantaan virus and 5-15% for Dobrava virus. For survivors, convalescence can take several months but recovery is often complete.

Medical and Physical Countermeasures.

Vaccination (Immunoprophylaxis)

Vaccines are not available.

 Specific Therapy

Ribavirin is effective against Hantaan virus and was made available for post-exposure prophylaxis to soldiers in Operation Desert Shield/Storm and in Korea. The disease is endemic in Korea.

Supportive care

Supportive care such as dialysis to support the kidneys, maintenance of blood volume.

Decontamination

These viruses are killed by heat, sodium hypochlorite (1%), glutaraldehyde (2%) and ethanol (70%).

Agent Properties and Potential Uses

These viruses are spread naturally by aerosols and there are numerous reports of laboratory acquired infections of Hantaan virus from urine aerosols from its natural hosts (rodents, especially mice). It may be transmissible from man to man but there are no definitive data.

These viruses arenot spread by an insect vector and appears to be relatively hardy outside the host. It uses rodents as a reservoir and prolonged monitoring of local rodent populations for the virus may be necessary in the aftermath of an attack.

These virus are members of a group of closely related viruses, including Sin Nombre or Four Corners virus that causes Hantavirus Pulmonary Syndrome; Seoul virus and Puumala virus are have world-wide spread and may aid in deniability of an attack and delay identification of use of the agent.

Terrorist Acquisition and Attempted Use.

• None confirmed.