Imported Case of Marburg Hemorrhagic Fever — Colorado, 2008

N Fujita, MD; A Miller; G Miller, DVM; K Gershman, MD; N Gallagher; N Marano, DVM; C Hale, DVM; E Jentes, PhD

Disclosures

Morbidity and Mortality Weekly Report. 2009;58(49):1377-1381. 

In This Article

Editorial Note

Before the case described in this report, the only human cases of VHF imported into the United States were single cases of Lassa fever (an arenaviral hemorrhagic fever) in Chicago, Illinois, in 1989[5] and in Trenton, New Jersey, in 2004.[4] No previous cases of imported filovirus (MARV or Ebola virus) infections have been reported in the United States, making this the first imported case of a filoviral hemorrhagic fever in the United States.

The patient described in this report was first diagnosed by convalescent serology because initial testing of the day 10 sample was negative by virus isolation, antigen-detection, and IgM and IgG ELISA. After the Dutch patient was diagnosed with MHF, retesting of the archived specimen with more sensitive molecular methods was performed, including a nested RT-PCR assay that detected viral RNA. This, along with the positive convalescent serology and compatible clinical course, confirmed the diagnosis. To obtain a rapid diagnosis during the acute illness, patients with suspected VHF should have paired acute blood specimens (ideally collected during days 0–4 and days 4–9 of the acute illness) tested at a World Reference Laboratory (e.g., CDC) with biosafety level 4 capability using multiple methods as appropriate for the timing of the sample, including virus isolation, RT-PCR, and IgM and IgG ELISA. Because the incubation period for MARV is 2–21 days, daily contact tracing is recommended to contain outbreaks. This involves following all contacts of patients suspected of having MHF, and isolating and testing those that experience fever within 21 days after their last contact.

Other sporadic cases of MHF have been reported outside of Africa: two laboratory-acquired cases in Russia and two cases imported from endemic areas.[3,6] These imported cases occurred in a patient hospitalized in South Africa who likely acquired the disease while camping in Zimbabwe in 1975[6] and the second in the previously described Dutch patient hospitalized in the Netherlands who died of MHF after visiting the Python Cave in Uganda in 2008.[3] Case-fatality rates of 83%–90% have been reported for widespread outbreaks of MHF in Africa.[1,7]

Virologic and serologic evidence of MARV infection has been documented among cave-dwelling bats, particularly the Egyptian fruit bat Rousettus aegyptiacus;[2] this evidence has implicated bats as the likely natural reservoir for MARV. R. aegyptiacus bats have a wide range covering most of Africa, indicating that risk for zoonotic infection might exist beyond areas with previously documented cases. The precise route of MARV transmission from the putative bat reservoir to humans has not been determined and might include direct or indirect exposure to bat excretions and secretions. MHF outbreaks have resulted from exposure to caves or mines inhabited by bats[1,8] and subsequent human-to-human transmission through direct contact with infectious body fluids and contaminated materials, primarily affecting caregivers and health-care workers.[8,9] Isolation of suspected patients and implementation of droplet and contact precautions are recommended to prevent person-to-person spread.

Although the Python Cave is closed and no additional MHF cases have been reported, travelers should be aware of the risk for acquiring MHF in endemic areas in Africa and should avoid entering caves or mines inhabited by bats in these areas.[10] Health-care providers should have a low threshold of suspicion for VHF among travelers returning from endemic areas, promptly implement appropriate infection control measures, and rapidly report suspected cases. Suspected cases of VHF are nationally notifiable and should be reported immediately to local and state health departments and to CDC's Special Pathogens Branch at 404-639-1115 (770-488-7100 after hours) to obtain guidance on testing, management, and response. Additional information regarding Marburg hemorrhagic fever,§ travelers' health, and VHF infection-control guidelines** are available online.

* Nested RT-PCR is more sensitive and specific than traditional RT-PCR. A portion of the product produced from the first round of amplification is used in the second round of amplification along with a different set of primers.
Based on CDC's Interim Guidance for Managing Patients with Suspected Viral Hemorrhagic Fever in U.S. Hospitals, available at http://www.cdc.gov/ncidod/dhqp/bp_vhf_interimguidance.html.
§ Available at http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/marburg.htm.
Available at http://wwwn.cdc.gov/travel.
** Available at http://www.cdc.gov/ncidod/dhqp/bp_vhf_interimguidance.html.

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