Marburgvirus
Classification
Viruses; ssRNA viruses; ssRNA negative-strand viruses; Mononegavirales; Filoviridae
Species
Marburgvirus Marburg
Description and Significance
Marburg is an extremely dangerous virus as it has a human fatality rate of 25%, with outbreaks are impossible to predict or prevent.[1] Marburgvirus was the first ever filovirus recognized, discovered in 1967 when laboratory workers in Marburg, Germany developed hemorrhagic fever after handling tissue of African green monkeys from Uganda. The 1967 outbreak proved fatal in seven of the 37 cases. In 1975 the virus reemerged in Johannesburg, South Africa in a person who had been traveling in Zimbabwe. A traveling companion and a nurse of the person became infected. In 1980, another man who had been traveling near the same region became infected and transmitted the virus to his physician. Another Marburg infection was recognized in 1987 of a traveling man who became ill and soon died. In 1998, an outbreak occurred in Congo amongst individuals who had been working in a gold mine. Attempts to isolate the virus from all locations were unsuccessful. Since then, cases of Marburgvirus have been rare and sporadic, the most recent occurring in 2005, causing several fatalities in Angola. The only other filovirus is the Ebola virus, discovered after Marburg in 1976.[3] The natural origins and reservoirs remain a complete mystery.[1]
Genome Structure
Filoviruses are enveloped, nonsegmented negative-stranded RNA viruses. The two species, Marburg and Ebola virus, are genetically distinct with 7 genes and a total molecular length of approximately 19 kb (19112 bp), making them the owners of the largest known genomes of negative-strand RNA viruses. The virions appear long and filamentous, occasionally branched. In addition, the virions may appear as "6"-shaped, "U"-shaped, or circular configurations. [1][2]
Cell Structure, Metabolism and Life Cycle
Interesting features of cell structure; how it gains energy; what important molecules it produces.
Ecology and Pathogenesis
The natural history and origin of Marburg viruses remain a total mystery. It appears to be transmitted zoonotically; with human infection occuring from animals. However, all attempts to trace human cases have failed to uncover the reservoir. Speculations point to bats and rodents as probable reservoirs. Whatever the origin, human to human contact is the main route of infection and transmission in human filoviral hemorrhagic fever outbreaks. Marburg virus has been transmitted to primates by aerosol in laboratory experiments. [1] "Recorded cases of the disease are rare, and have appeared in only a few locations. While the 1967 outbreak occurred in Europe, the disease agent had arrived with imported monkeys from Uganda. No other case was recorded until 1975, when a traveler most likely exposed in Zimbabwe became ill in Johannesburg, South Africa and passed the virus to his traveling companion and a nurse. 1980 saw two other cases, one in Western Kenya not far from the Ugandan source of the monkeys implicated in the 1967 outbreak. The attending physician of this patient in Nairobi became the second case. Another human Marburg infection was recognized in 1987 when a young man who had traveled extensively in Kenya, including western Kenya, became ill and later died. In 1998, an outbreak occurred in Durba, Democratic Republic of the Congo. Cases were linked to individuals working in a gold mine. After the outbreak subsided, there were still some sporadic cases that occurred in the region." [3][2]
References
[1] Beer et al., 1999: Beer Brigitte, Kurth Reinhard, Bukreyev Alexander Characteristics of Filoviridae: Marburg and Ebola viruses. Naturwissenschaften. 1999; 86(1): 8 - 17. [PubMed: 10024977].
[2] Marburg Virus Transmission [ http://staff.vbi.vt.edu/pathport/pathinfo/pathogens/Marburg_virus_2.html#Marburg_virus ] .
[3] Marburg Hemorrhagic Fever [ http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/marburg.htm ].
Author
Page authored by Justin Aden, student of Prof. Jay Lennon at Michigan State University.
