12/11/2023: Lab Advisory: Clinical Testing Guidance for Patients with Suspected Viral Hemorrhagic Fevers

CDC's Laboratory Outreach Communication System (LOCS)

Audience: Clinical Laboratories

Level: Laboratory Advisory

Viral hemorrhagic fevers (VHF) are a group of diseases caused by several distinct families of viruses. The term “viral hemorrhagic fever” refers to a condition that affect many organ systems of the body, damages the overall cardiovascular system, and reduces the body’s ability to function on its own.

VHFs are endemic in areas of Africa, Asia, the Middle East and South America and are caused by infection with any of the following viruses: ebolaviruses, marburgviruses, Crimean-Congo hemorrhagic fever virus, arenaviruses (Lassa, Lugo, and South American hemorrhagic fever viruses), and Nipah virus.

While the risk of VHFs being brought into the US by travelers is very low, CDC recommends that clinical laboratories review the testing guidance, which currently applies for the VHFs listed above:

Note: The guidance listed here for ebolaviruses also applies to the other VHFs listed above.

Travelers who feel sick after returning from areas experiencing a VHF outbreak are more likely to have other febrile infections such as malaria, rather than VHF infections, particularly if they do not report an epidemiologic risk factor within 21 days before symptom onset.

Clinical laboratories should concurrently test for other more likely febrile illnesses while VHF testing is underway. Laboratories can safely perform common diagnostic testing by following Standard Precautions when handling all patient specimens. Clinical laboratories should conduct a site and activity-specific risk assessment that takes into account patient specimens, type, characteristics, and instrumentation being used for testing. Laboratories should ensure appropriate safety measures are in place, and all laboratory work must comply with the Bloodborne Pathogen Standard.

Additionally, laboratory equipment can be maintained as it normally would with any other bloodborne pathogen, and as recommended in the Bloodborne Pathogen Standard. Most blood testing instruments are closed systems that do not require any decontamination between patient specimens. However, laboratories should consult the instructions or manufacturers directly for more support, if needed. You can find more information regarding decontamination of testing surfaces and instruments on the Ebola and Marburg web pages.

Clinicians with concerns about VHF in a patient should contact their jurisdictional health department immediately via the 24-hour Epi-On-Call contact list and follow protocols for patient assessment. Clinical teams should coordinate with public health officials and CDC to assess the risk of VHF based on the clinical presentation and epidemiologic risk factors to determine if VHF testing is needed and if other causes of illness should be considered (e.g., malaria). Timely identification of other more likely pathogens and access to routine laboratory testing, such as blood counts and chemistries, is essential for appropriate patient care.

CDC’s Viral Special Pathogens Branch (VSPB) is available 24/7 to public health departments for consultations on suspect VHF cases by calling the CDC Emergency Operations Center at 770-488-7100 and requesting VSPB’s on-call epidemiologist.

If testing determines a patient has a VHF, clinical teams should coordinate with public health officials and CDC to ensure appropriate precautions are taken to help prevent the potential spread and coordinate care.

We encourage you to share this message widely with your network(s).

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Thank you,

The Laboratory Outreach Communication System

Laboratory Outreach Communication System (LOCS) | Division of Laboratory Systems (DLS)

Center for Laboratory Systems and Response (CLSR)

Centers for Disease Control and Prevention (CDC)