Marburg virus facts for kids
Quick facts for kids Marburg virus |
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| Transmission electron micrograph of Marburg virus | |
Virus classification  |
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| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Negarnaviricota |
| Class: | Monjiviricetes |
| Order: | Mononegavirales |
| Family: | Filoviridae |
| Genus: | Marburgvirus |
| Species: |
Marburg marburgvirus
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| Virus: |
Marburg virus
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Marburg virus (MARV) is a hemorrhagic fever virus of the Filoviridae family of viruses and a member of the species Marburg marburgvirus, genus Marburgvirus. It causes Marburg virus disease in primates, a form of viral hemorrhagic fever. The virus is considered to be extremely dangerous. The World Health Organization (WHO) rates it as a Risk Group 4 Pathogen (requiring biosafety level 4-equivalent containment). In the United States, the National Institute of Allergy and Infectious Diseases ranks it as a Category A Priority Pathogen and the Centers for Disease Control and Prevention lists it as a Category A Bioterrorism Agent. It is also listed as a biological agent for export control by the Australia Group.
The virus can be transmitted by exposure to one species of fruit bats or it can be transmitted between people via body fluids and broken skin. The disease can cause haemorrhage, fever, and other symptoms similar to Ebola, which belongs to the same family of viruses. According to the WHO, there are no approved vaccines or antiviral treatment for Marburg, but early, professional treatment of symptoms like dehydration considerably increases survival chances.
In 2009, expanded clinical trials of an Ebola and Marburg vaccine began in Kampala, Uganda.
Human disease
MARV is one of two Marburg viruses that causes Marburg virus disease (MVD) in humans (in the literature also often referred to as Marburg hemorrhagic fever, MHF). The other one is Ravn virus (RAVV). Both viruses fulfill the criteria for being a member of the species Marburg marburgvirus because their genomes diverge from the prototype Marburg marburgvirus or the Marburg virus variant Musoke (MARV/Mus) by <10% at the nucleotide level.
Recorded outbreaks
| Year | Geographic location | Virus | Human cases | Human deaths | Case fatality rate | Notes |
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| 1967 | Marburg and Frankfurt, West Germany, and Belgrade, Socialist Federal Republic of Yugoslavia | MARV | 31 | 7 | 23% | laboratory leak |
| 1975 | Rhodesia and Johannesburg, South Africa | MARV | 3 | 1 | 33% | |
| 1980 | Kenya | MARV | 2 | 1 | 50% | |
| 1987 | Kenya | RAVV | 1 | 1 | 100% | |
| 1988 | Koltsovo, Soviet Union | 1 | 1 | 100% | laboratory accident | |
| 1990 | Koltsovo, Soviet Union | MARV | 1 | 1 | 100% | laboratory accident |
| 1998–2000 | Durba and Watsa, Democratic Republic of the Congo | MARV & RAVV | 154 | 128 | 83% | Two different marburgviruses, MARV and Ravn virus (RAVV), cocirculated and caused disease. The number of cases and deaths due to MARV or RAVV infection have not been reported. |
| 2004–2005 | Angola | MARV | 374 | 329 | 90% | |
| 2007 | Uganda | MARV & RAVV | 4 | 1 | 25% | |
| 2008 | Uganda and The Netherlands | MARV | 1 | 1 | 100% | |
| 2012 | Uganda | MARV | 18 | 9 | 50% | |
| 2014 | Uganda | MARV | 1 | 1 | 100% | |
| 2017 | Uganda | MARV | 3 | 3 | 100% | |
| 2021 | Guinea | MARV | 1 | 1 | 100% | The Guinean government detected the case from a sample of patients who died on August 2, 2021, in the southern prefecture of Gueckedou near the country's borders with Sierra Leone and Liberia. |
| 2022 | Ghana | MARV | 4 | 3 | 75% | Four cases have been reported so far with preparations for a possible outbreak being made. On 17 July 2022, two cases were confirmed by Ghana, with two more being subsequently confirmed on 27 July 2022.
See Ghana Marburg virus outbreak 2022. |
| Feb 2023 | Equatorial Guinea | 25 | 11 | 44% | See Equatorial Guinea Marburg virus outbreak 2023. | |
| Mar 2023 | Tanzania | 8 | 5 | 63% |
Prevention
The first clinical study testing the efficacy of a Marburg virus vaccine was conducted in 2014. The study tested a DNA vaccine and concluded that individuals inoculated with the vaccine exhibited some level of antibodies. However, these vaccines were not expected to provide definitive immunity. Several animal models have shown to be effective in the research of Marburg virus, such as hamsters, mice, and non-human primates (NHPs). Mice are useful in the initial phases of vaccine development as they are ample models for mammalian disease, but their immune systems are still different enough from humans to warrant trials with other mammals. Of these models, the infection in macaques seems to be the most similar to the effects in humans. A variety of other vaccines have been considered. Virus replicon particles (VRPs) were shown to be effective in guinea pigs, but lost efficacy once tested on NHPs. Additionally, an inactivated virus vaccine proved ineffective. DNA vaccines showed some efficacy in NHPs, but all inoculated individuals showed signs of infection.
Because Marburg virus and Ebola virus belong to the same family, Filoviridae, some scientists have attempted to create a single-injection vaccine for both viruses. This would both make the vaccine more practical and lower the cost for developing countries. Using a single-injection vaccine has shown to not cause any adverse reactogenicity, which the possible immune response to vaccination, in comparison to two separate vaccinations.
As of June 23, 2022, researchers working with the Public Health Agency of Canada conducted a study which showed promising results of a recombinant vesicular stomatitis virus (rVSV) vaccine in guinea pigs, entitled PHV01. According to the study, inoculation with the vaccine approximately one month prior to infection with the virus provided a high level of protection.
Even though there is much experimental research on Marburg virus, there is still no prominent vaccine. Human vaccination trials are either ultimately unsuccessful or are missing data specifically regarding Marburg virus. Due to the cost needed to handle Marburg virus at qualified facilities, the relatively few number of fatalities, and lack of commercial interest, the possibility of a vaccine has simply not come to fruition.
See also
In Spanish: Marburgvirus para niños
