Marburgviruses: An Update

Caterina M. Miraglia, DC, MLS(ASCP)

Disclosures

Lab Med. 2019;50(1):16-28. 

In This Article

Transmission

Transmission to humans can occur from exposure to the host reservoir, so entry into R. aegyptiacus roosting sites in endemic areas should be avoided.[30,31] Between August 2008 and November 2009, R. aegyptiacus bats from Python Cave in Uganda, the site where American and Dutch tourists were infected (Table 1), were collected. Marburgviruses were detected, and there was a higher prevalence in juvenile bats. R. aegyptiacus gives birth twice a year (February and August). It was noted[32] that most MVD outbreaks overlapped with the birthing seasons and maturation of the juvenile bats to approximately 4.5 to 7.5 months of age (mid-June–mid-September, and mid-December–mid-March), thus, there seems to be an increased risk to humans during these time periods. Also, transmission can occur when there is contact with ill NHPs.[30,31]

The infection can spread from person to person through direct contact with bodily fluids and through contact with contaminated fomites (objects or materials that are likely to carry infection).[30] MARV can survive for 4 to 5 days on contaminated surfaces.[33] Disinfection can be achieved using bleach or phenolic disinfectants. Marburgviruses are inactivated by 1% sodium hypochlorite, 2% gluteraldehyde, formaldehyde, paraformaldehyde, formalin, 3% acetic acid, lipid solvents, detergents, heat, gamma radiation, and ultraviolet radiation.[34–37]

The results of a seroprevalence study[38] have demonstrated that asymptomatic individuals possess antibodies to MARV. In 2011, in the Democratic Republic of Congo, 809 healthy blood donors with no history of VHF had serum specimens tested for the presence of IgG antibodies to MARV and EBOV using indirect double-immunofluorescence microscopy. Most of the blood donors were from urban areas. The MARV seroprevalence was 0.5%, and the EBOV seroprevalence was 2.5%. The independent risk factors associated with seropositivity to EBOV were exposure to birds and exposure to bats. No risk factors were recognized in people with antibodies to MARV.

In a retrospective seroprevalence study conducted in Sierra Leone,[39] 675 serum specimens submitted for testing between 2007 and 2014 for suspected Lassa fever were evaluated with a multiplex assay on the magnetic bead–based MAGPIX multiplexing system (Thermo Fisher Scientific), which is used to detect antibodies to various viral pathogens. The rate of positive results for IgG antibodies to MARV was 10.7%.

Serum specimens were tested from survivors of SUDV, BDBV, and MARV outbreaks to detect whether immunity was still present and whether there was cross-reactivity of the antibodies with other filoviruses. Sera from the MARV survivors were collected 1 year after infection. Testing was performed using a microarray assay with recombinant proteins (VP40, NP, and GP) of EBOV, SUDV, BDBV, TAFV, RESTV, and MARV, as well as with whole inactivated viruses. MARV sera still demonstrated high reactivity and had the lowest amount of cross-reactivity, compared to sera from SUDV and BDBV survivors.[40] It is uncertain whether these antibodies would be protective in the event of another exposure to the same or to a different filovirus.[38,40]

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