Report all suspected cases of Viral Hemorrhagic Fevers immediately to Public Health - Seattle & King County by calling 206-296-4774.

• Viral hemorrhagic fevers (VHF) are caused by a group of single-stranded RNA viruses from four families: Arenaviruses, bunyaviruses, filoviruses, and flaviviruses.
• Humans are infected via the bite of an infected arthropod, inhalation of rodent excreta, or contact with infected animal carcasses.
• Person-to-person transmission is possible with several agents, primarily through blood or body fluid exposure, and rarely, via airborne transmission.

Viral Hemorrhagic Fevers and Bioterrorism

• Agents of concern for potential use as a biological weapon include the arenaviruses, filoviruses, hantaviruses, tick-borne hemorrhagic fever viruses and yellow fever.

• All agents have an initial febrile prodrome with non-specific symptoms: headache, malaise,
• fatigue/exhaustion, arthralgia, myalgia, nausea, dizziness, non-bloody diarrhea.
• Clinical signs reflect vascular involvement with increased capillary permeability.
• Ebola, Marburg, Rift Valley fever, and Crimean-Congo hemorrhagic fever viruses can cause disseminated intravascular coagulation (DIC); other viruses generally do not.
• Illness onset is typically abrupt with filoviruses, flaviviruses, and Rift Valley fever, and more insidious with arenaviruses.
• A maculopapular rash appears about five days after onset of illness caused by filoviruses.
• Jaundice may be prominent in filovirus infections, Lassa fever, Rift Valley fever, and yellow fever.
• Meningoencephalitis can occur in Rift Valley fever, Kyasunar Forest disease, and Omsk hemorrhagic fever.
• Severe exudative pharyngitis is a characteristic early feature of Lassa fever.

• Contact Public Health for patients with suspected VHF and the following clinical criteria:
  • Fever (101ºF) for less than three weeks,
  • Severe illness and no predisposing factors for hemorrhagic manifestations,
  • And at least two of the following hemorrhagic symptoms: hemorrhagic or purple rash, epistaxis, hematemesis, hemoptysis, blood in stools, other, and no established alternative diagnosis.

• Evaluation should include a travel history and inquiry about exposure to ticks, mosquitoes, animals, and ill persons.
• Laboratory diagnostic tests (blood/serum and other body fluids) are performed at public health labs.
  • Antigen detection by antigen-capture ELISA
  • Serology
  • RT-PCR
  • Immunohistochemistry
  • Electron microscopy
  • Viral isolation (performed at CDC)

• Airborne and contact precautions should be followed by all health care, environmental, and laboratory workers when VHF is suspected.
• Patients should be placed in a negative pressure room and dedicated medical equipment used, if available.
• Patients recovering from an arenavirus or filovirus infection should refrain from sexual activity for three months post-recovery.

• Treatment is primarily supportive.
  • Correct coagulopathies as needed.
  • Avoid anticoagulant therapies, anti-platelet drugs, and intramuscular injections.
  • Maintain fluid and electrolyte balance.
• Ribavirin may be available under an investigational new drug protocol for patients with arenavirus or bunyavirus infection.
• Refer to www.bt.cdc.gov for current treatment and prophylaxis guidelines.

• Persons exposed to VHF should be monitored for fever or hemorrhagic symptoms for 21 days post-exposure.
• Ribavirin may have a role in the prophylaxis of symptomatic persons exposed to arenaviruses or bunyaviruses.
• The only vaccine currently commercially available for VHF is a live-virus vaccine for yellow fever vaccine.
  • Recommended for travelers to endemic areas of South America and Africa and laboratory personnel.
  • Not useful for post-exposure prophylaxis because the time-to-immunity post-vaccination (10 days) is longer than the disease incubation period (three to six days).
• Vaccines against Argentine hemorrhagic fever and Rift Valley fever are available as investigational new drugs, and research is underway to develop vaccines against other VHF viruses.

• Centers for Disease Control and Prevention
• Infectious Disease Society of America
• Center for Biosecurity of UPMC
• Bioterrorism preparedness training modules
• Washington State Department of Health