Marburgvirus Genomics and Association with a Large Hemorrhagic Fever Outbreak in Angola

Abstract

In March 2005, the Centers for Disease Control and Prevention (CDC) investigated a large hemorrhagic fever (HF) outbreak in Uige Province in northern Angola, West Africa. In total, 15 initial specimens were sent to CDC, Atlanta, Ga., for testing for viruses associated with viral HFs known to be present in West Africa, including ebolavirus. Marburgvirus was also included despite the fact that the origins of all earlier outbreaks were linked directly to East Africa. Surprisingly Remarkably few nucleotide differences were found among the Angolan clinical specimens (0 to 0.07%), consistent with an outbreak scenario in which a single (or rare) introduction of virus from the reservoir species into the human population was followed by person-to-person transmission with little accumulation of mutations. This is in contrast to the 1998 to 2000 marburgvirus outbreak, where evidence of several virus genetic lineages (with up to 21% divergence) and multiple virus introductions into the human population was found.

Post-exposure treatments for Ebola and Marburg virus infections

“…The exception is the Angola strain of MARV, for which there is no obvious difference between the macaque species 50,63 . Of note, there are substantial differences in the disease course in the highly pathogenic MARV Angola strain (associated with 90% fatality rates in humans 240 ), which causes a more rapid disease course with a shorter therapeutic window in macaques than does the seemingly less pathogenic Musoke strain 50,63,162,191,194 . Historically, many of the preclinical NHP studies with MARV were conducted with the Musoke strain, which makes it difficult to compare results with current studies that use the Angola strain, which presents a much higher bar for protection.…”

How Ebola and Marburg viruses battle the immune system

“…Studies of ZEBOV have identified bats as potentially being among the natural hosts for ebolaviruses 87 , and epidemiological evidence for MARV is also consistent with bats being the wildlife reservoirs of these viruses. The impact of these viruses on individual bats and bat populations is relatively unknown, but the consequences of filoviral infections in humans and non-human primates can be devastating: an acute disease with human mortality rates as high as 89% for sizeable outbreaks of either ZEBOV 88 or MARV 89 . The viruses are apparently even more deadly in non-human primates than humans, with mortality rates approaching 100% in most non-human primate species, including the ebolavirus species for which human disease is rare (Ivory Coast ebolavirus) or has not been observed at all (Reston ebolavirus) 90 .…”

Molecular Evolution of Viruses of the Family Filoviridae Based on 97 Whole-Genome Sequences

“…In contrast to the genus Ebolavirus, the genus Marburgvirus contains a single virus species (Marburg marburgvirus), albeit consisting of two distinct viruses, Marburg virus and Ravn virus (2), which are approximately 20% divergent from one another (3). The filoviruses are primarily African in origin, with the exception of Reston virus, which so far has been found only in the Philippines or in nonhuman primates originating in the Philippines.…”

“…Finally, Taï Forest virus has been described only in a single nonfatal human case (13). Marburg and Ravn virus infections can result in case fatalities ranging from approximately 20% to 90% (3,14,15).…”