Marburg virus disease | |
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Other names | Marburg hemorrhagic fever |
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Transmission electron micrograph of Marburg virus | |
Specialty | Infectious diseases ![]() |
Symptoms | Fever, weakness, muscle pain [1] |
Usual onset | 2–21 days after exposure [1] |
Causes | MV [1] |
Risk factors | Direct contact with bodily fluids of individuals infected with the virus [1] |
Diagnostic method | Blood test [1] |
Differential diagnosis | Ebola virus disease [1] |
Treatment | There is no treatment, only immediate supportive care [1] |
Frequency | Rare |
Deaths | 24–88% case fatality rate [2] |
Marburg virus disease (MVD), formerly Marburg hemorrhagic fever (MHF) is a viral hemorrhagic fever in human and non-human primates caused by either of the two Marburgviruses: Marburg virus (MARV) and Ravn virus (RAVV). [3] Its clinical symptoms are very similar to those of Ebola virus disease (EVD). [1]
Egyptian fruit bats are believed to be the normal carrier in nature and Marburg virus RNA has been isolated from them. [4]
The most detailed study on the frequency, onset, and duration of MVD clinical signs and symptoms was performed during the 1998–2000 mixed MARV/RAVV disease outbreak. [5] A skin rash, red or purple spots (e.g. petechiae or purpura), bruises, and hematomas (especially around needle injection sites) are typical hemorrhagic manifestations. However, contrary to popular belief, hemorrhage does not lead to hypovolemia and is not the cause of death (total blood loss is minimal except during labor). Instead, death occurs due to multiple organ dysfunction syndrome (MODS) due to fluid redistribution, hypotension, disseminated intravascular coagulation, and focal tissue necroses. [5] [6] [7] [8]
Clinical phases of Marburg hemorrhagic fever's presentation are described below. Note that phases overlap due to variability between cases.
Species name | Virus name (Abbreviation) |
Marburg marburgvirus * | Marburg virus (MARV; previously MBGV) |
Ravn virus (RAVV; previously MARV-Ravn) | |
"*" denotes the type species. |
MVD is caused by two viruses; Marburg virus (MARV) and Ravn virus (RAVV), family Filoviridae. [10] : 458
Marburgviruses are endemic in arid woodlands of equatorial Africa. [11] [12] [13] Most marburgvirus infections were repeatedly associated with people visiting natural caves or working in mines. In 2009, the successful isolation of infectious MARV and RAVV was reported from healthy Egyptian fruit bat caught in caves. [4] [14] This isolation strongly suggests that Old World fruit bats are involved in the natural maintenance of marburgviruses and that visiting bat-infested caves is a risk factor for acquiring marburgvirus infections. Further studies are necessary to establish whether Egyptian rousettes are the actual hosts of MARV and RAVV or whether they get infected via contact with another animal and therefore serve only as intermediate hosts. Another risk factor is contact with nonhuman primates, although only one outbreak of MVD (in 1967) was due to contact with infected monkeys. [15]
Contrary to Ebola virus disease (EVD), which has been associated with heavy rains after long periods of dry weather, [12] [16] triggering factors for spillover of marburgviruses into the human population have not yet been described.
MVD is clinically indistinguishable from Ebola virus disease (EVD), and it can also easily be confused with many other diseases prevalent in Equatorial Africa, such as other viral hemorrhagic fevers, falciparum malaria, typhoid fever, shigellosis, rickettsial diseases such as typhus, cholera, gram-negative sepsis, borreliosis such as relapsing fever or EHEC enteritis. Other infectious diseases that ought to be included in the differential diagnosis include leptospirosis, scrub typhus, plague, Q fever, candidiasis, histoplasmosis, trypanosomiasis, visceral leishmaniasis, hemorrhagic smallpox, measles, and fulminant viral hepatitis. Non-infectious diseases that can be confused with MVD are acute promyelocytic leukemia, hemolytic uremic syndrome, snake envenomation, clotting factor deficiencies/platelet disorders, thrombotic thrombocytopenic purpura, hereditary hemorrhagic telangiectasia, Kawasaki disease, and even warfarin intoxication. [17] [18] [19] [20] The most important indicator that may lead to the suspicion of MVD at clinical examination is the medical history of the patient, in particular the travel and occupational history (which countries and caves were visited?) and the patient's exposure to wildlife (exposure to bats or bat excrements?). MVD can be confirmed by isolation of marburgviruses from or by detection of marburgvirus antigen or genomic or subgenomic RNAs in patient blood or serum samples during the acute phase of MVD. Marburgvirus isolation is usually performed by inoculation of grivet kidney epithelial Vero E6 or MA-104 cell cultures or by inoculation of human adrenal carcinoma SW-13 cells, all of which react to infection with characteristic cytopathic effects. [21] [22] Filovirions can easily be visualized and identified in cell culture by electron microscopy due to their unique filamentous shapes, but electron microscopy cannot differentiate the various filoviruses alone despite some overall length differences. [23] Immunofluorescence assays are used to confirm marburgvirus presence in cell cultures. During an outbreak, virus isolation and electron microscopy are most often not feasible options. The most common diagnostic methods are therefore RT-PCR [24] [25] [26] [27] [28] in conjunction with antigen-capture ELISA, [29] [30] [31] which can be performed in field or mobile hospitals and laboratories. Indirect immunofluorescence assays (IFAs) are not used for diagnosis of MVD in the field anymore.[ citation needed ]
Marburg virus disease (MVD) is the official name listed in the World Health Organization's International Statistical Classification of Diseases and Related Health Problems 10 (ICD-10) for the human disease caused by any of the two marburgviruses Marburg virus (MARV) and Ravn virus (RAVV). In the scientific literature, Marburg hemorrhagic fever (MHF) is often used as an unofficial alternative name for the same disease. Both disease names are derived from the German city Marburg, where MARV was first discovered. [15]
The details of the initial transmission of MVD to humans remain incompletely understood. Transmission most likely occurs from Egyptian fruit bats or another natural host, such as non-human primates or through the consumption of bushmeat, but the specific routes and body fluids involved are unknown. Human-to-human transmission of MVD occurs through direct contact with infected bodily fluids such as blood. [4] Transmission events are relatively rare – there have been only 11 recorded outbreaks of MARV between 1975 and 2011, with one event involving both MARV and RAVV. [32]
There are currently no Food and Drug Administration-approved vaccines for the prevention of MVD. Many candidate vaccines have been developed and tested in various animal models. [33] [34] [35] Of those, the most promising ones are DNA vaccines [36] or based on Venezuelan equine encephalitis virus replicons, [37] vesicular stomatitis Indiana virus (VSIV) [34] [38] or filovirus-like particles (VLPs) [35] as all of these candidates could protect nonhuman primates from marburgvirus-induced disease. DNA vaccines have entered clinical trials. [39] Marburgviruses are highly infectious, but not very contagious. They do not get transmitted by aerosol during natural MVD outbreaks. Due to the absence of an approved vaccine, prevention of MVD therefore relies predominantly on quarantine of confirmed or high probability cases, proper personal protective equipment, and sterilization and disinfection.[ citation needed ]
The natural maintenance hosts of marburgviruses remain to be identified unequivocally. However, the isolation of both MARV and RAVV from bats and the association of several MVD outbreaks with bat-infested mines or caves strongly suggests that bats are involved in Marburg virus transmission to humans. Avoidance of contact with bats and abstaining from visits to caves is highly recommended, but may not be possible for those working in mines or people dependent on bats as a food source.[ citation needed ]
Since marburgviruses are not spread via aerosol, the most straightforward prevention method during MVD outbreaks is to avoid direct (skin-to-skin) contact with patients, their excretions and body fluids, and any possibly contaminated materials and utensils. Patients should be isolated, but still are safe to be visited by family members. Medical staff should be trained in and apply strict barrier nursing techniques (disposable face mask, gloves, goggles, and a gown at all times). Traditional burial rituals, especially those requiring embalming of bodies, should be discouraged or modified, ideally with the help of local traditional healers. [40]
Marburgviruses are World Health Organization Risk Group 4 Pathogens, requiring Biosafety Level 4-equivalent containment, [41] laboratory researchers have to be properly trained in BSL-4 practices and wear proper personal protective equipment.
There is currently no effective marburgvirus-specific therapy for MVD. Treatment is primarily supportive in nature and includes minimizing invasive procedures, balancing fluids and electrolytes to counter dehydration, administration of anticoagulants early in infection to prevent or control disseminated intravascular coagulation, administration of procoagulants late in infection to control hemorrhaging, maintaining oxygen levels, pain management, and administration of antibiotics or antifungals to treat secondary infections. [42] [43]
Although supportive care can improve survival chances, marburg virus disease is fatal in the majority of cases. As of 2023 [update] the case fatality rate was assessed to be 61.9%. [44]
The WHO identifies marburg virus disease as having pandemic potential. [44]
Below is a table of outbreaks concerning MVD from 1967 to 2023:
Year | Country | Virus | Human cases | Human deaths | Case fatality rate | Notes |
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1967 | ![]() ![]() | MARV | 31 | 7 | 23% | |
1975 | ![]() ![]() | MARV | 3 | 1 | 33% | |
1980 | ![]() | MARV | 2 | 1 | 50% | |
1987 | ![]() | RAVV | 1 | 1 | 100% | |
1988 | ![]() | MARV | 1 | 1 | 100% | |
1990 | ![]() | MARV | 1 | 0 | 0% | |
1998–2000 | ![]() | MARV & RAVV | 154 | 128 | 83% | |
2004–2005 | ![]() | MARV | 252 | 227 | 90% | |
2007 | ![]() | MARV & RAVV | 4 | 1 | 25% | [46] |
2008 | ![]() ![]() ![]() | MARV | 2 | 1 | 50% | [47] |
2012 | ![]() | MARV | 18 | 9 | 50% | [48] [49] |
2014 | ![]() | MARV | 1 | 1 | 100% | [50] [51] |
2017 | ![]() | MARV | 3 | 3 | 100% | [52] |
2021 | ![]() | MARV | 1 | 1 | 100% | [53] [54] [55] |
2022 | ![]() | MARV | 3 | 2 | 66.66% | [56] |
2023 | ![]() | MARV | 40 | 35 | 88% | [57] [58] [59] |
2023 | ![]() | MARV | 9 | 6 | 66% | [60] [61] |
MVD was first documented in 1967, when 31 people became ill in the German towns of Marburg and Frankfurt am Main, and in Belgrade, Yugoslavia. The outbreak involved 25 primary MARV infections and seven deaths, and six nonlethal secondary cases. The outbreak was traced to infected grivets (species Chlorocebus aethiops) imported from an undisclosed location in Uganda and used in developing poliomyelitis vaccines. The monkeys were received by Behringwerke, a Marburg company founded by the first winner of the Nobel Prize in Medicine, Emil von Behring. The company, which at the time was owned by Hoechst, was originally set up to develop sera against tetanus and diphtheria. Primary infections occurred in Behringwerke laboratory staff while working with grivet tissues or tissue cultures without adequate personal protective equipment. Secondary cases involved two physicians, a nurse, a post-mortem attendant, and the wife of a veterinarian. All secondary cases had direct contact, usually involving blood, with a primary case. Both physicians became infected through accidental skin pricks when drawing blood from patients. [62] [63] [64] [65]
In 1975, an Australian tourist became infected with MARV in Rhodesia (today Zimbabwe). He died in a hospital in Johannesburg, South Africa. His girlfriend and an attending nurse were subsequently infected with MVD, but survived. [66] [67] [68]
A case of MARV infection occurred in 1980 in Kenya. A French man, who worked as an electrical engineer in a sugar factory in Nzoia (close to Bungoma) at the base of Mount Elgon (which contains Kitum Cave), became infected by unknown means and died on 15 January shortly after admission to Nairobi Hospital. [69] The attending physician contracted MVD, but survived. [70] A popular science account of these cases can be found in Richard Preston's book The Hot Zone (the French man is referred to under the pseudonym "Charles Monet", whereas the physician is identified under his real name, Shem Musoke). [71]
In 1987, a single lethal case of RAVV infection occurred in a 15-year-old Danish boy, who spent his vacation in Kisumu, Kenya. He had visited Kitum Cave on Mount Elgon prior to travelling to Mombasa, where he developed clinical signs of infection. The boy died after transfer to Nairobi Hospital. [72] A popular science account of this case can be found in Richard Preston's book The Hot Zone (the boy is referred to under the pseudonym "Peter Cardinal"). [71]
In 1988, researcher Nikolai Ustinov infected himself lethally with MARV after accidentally pricking himself with a syringe used for inoculation of guinea pigs. The accident occurred at the Scientific-Production Association "Vektor" (today the State Research Center of Virology and Biotechnology "Vektor") in Koltsovo, USSR (today Russia). [73] Very little information is publicly available about this MVD case because Ustinov's experiments were classified. A popular science account of this case can be found in Ken Alibek's book Biohazard. [74]
Another laboratory accident occurred at the Scientific-Production Association "Vektor" (today the State Research Center of Virology and Biotechnology "Vektor") in Koltsovo, USSR, when a scientist contracted MARV by unknown means. [75]
A major MVD outbreak occurred among illegal gold miners around Goroumbwa mine in Durba and Watsa, Democratic Republic of Congo from 1998 to 2000, when co-circulating MARV and RAVV caused 154 cases of MVD and 128 deaths. The outbreak ended with the flooding of the mine. [5] [76] [77]
In early 2005, the World Health Organization (WHO) began investigating an outbreak of viral hemorrhagic fever in Angola, which was centered in the northeastern Uíge Province but also affected many other provinces. The Angolan government had to ask for international assistance, as there were only approximately 1,200 doctors in the entire country and provinces that had few as two. Health care workers also complained about a shortage of basic personal protective equipment. Médecins Sans Frontières (MSF) reported that when their team arrived at the provincial hospital at the center of the outbreak, they found it operating without water and electricity. Contact tracing was complicated by the fact that the country's roads and other infrastructure were devastated after nearly three decades of civil war and the countryside remained littered with land mines. [78]
Americo Boa Vida Hospital in the Angolan capital, Luanda, set up a special isolation ward to treat patients from the countryside. Due to the high fatality rate of MVD, some people came to be suspicious of and hostile towards hospitals and medical workers. For instance, a specially-equipped isolation ward at the provincial hospital in Uíge was reported to be empty during much of the epidemic, even though the facility was at the center of the outbreak. WHO was forced to implement what it described as a "harm reduction strategy" by distributing disinfectants to affected families who refused hospital care. Of the 252 people who contracted MVD, 227 died. [78] [79] [80] [81] [82] [83] [84]
In 2007, four miners became infected with marburgviruses in Kamwenge District, Uganda. The first case, a 29-year-old man, became symptomatic on July 4, 2007, was admitted to a hospital on July 7, and died on July 13. Contact tracing revealed that the man had had prolonged close contact with two colleagues (a 22-year-old man and a 23-year-old man), who experienced clinical signs of infection before his disease onset. Both men had been admitted to hospitals in June and survived their infections, which were proven to be due to MARV. A fourth, 25-year-old man, developed MVD clinical signs in September and was shown to be infected with RAVV. He also survived the infection. [14] [85]
On July 10, 2008, the Netherlands National Institute for Public Health and the Environment reported that a 41-year-old Dutch woman, who had visited Python Cave in Maramagambo Forest during her holiday in Uganda, had MVD due to MARV infection, and had been admitted to a hospital in the Netherlands. The woman died under treatment in the Leiden University Medical Centre in Leiden on July 11. The Ugandan Ministry of Health closed the cave after this case. [86] On January 9 of that year an infectious diseases physician notified the Colorado Department of Public Health and the Environment that a 44-year-old American woman who had returned from Uganda had been hospitalized with a fever of unknown origin. At the time, serologic testing was negative for viral hemorrhagic fever. She was discharged on January 19, 2008. After the death of the Dutch patient and the discovery that the American woman had visited Python Cave, further testing confirmed the patient demonstrated MARV antibodies and RNA. [87]
In October 2017 an outbreak of Marburg virus disease was detected in Kween District, Eastern Uganda. All three initial cases (belonging to one family – two brothers and one sister) had died by 3 November. The fourth case – a health care worker – developed symptoms on 4 November and was admitted to a hospital. The first confirmed case traveled to Kenya before the death. A close contact of the second confirmed case traveled to Kampala. It is reported that several hundred people may have been exposed to infection. [88] [89]
In August 2021, two months after the re-emergent Ebola epidemic in the Guéckédou prefecture was declared over, a case of the Marburg disease was confirmed by health authorities through laboratory analysis. [54] Other potential case of the disease in a contact awaits official results. This was the first case of the Marburg hemorrhagic fever confirmed to happen in West Africa. The case of Marburg also has been identified in Guéckédou. [53] During the outbreak, a total of one confirmed case, who died (CFR=100%), and 173 contacts were identified, including 14 high-risk contacts based on exposure. [90] Among them, 172 were followed for a period of 21 days, of which none developed symptoms. One high-risk contact was lost to follow up. [90] Sequencing of an isolate from the Guinean patient showed that this outbreak was caused by the Angola-like Marburg virus. [91] A colony of Egyptian rousettus bats (reservoir host of Marburg virus) was found in close proximity (4.5 km) to the village, where the Marburg virus disease outbreak emerged in 2021. [92] Two sampled fruit bats from this colony were PCR-positive on the Marburg virus. [92]
In July 2022, preliminary analysis of samples taken from two patients – both deceased – in Ghana indicated the cases were positive for Marburg. However, per standard procedure, the samples were sent to the Pasteur Institute of Dakar for confirmation. [93] On 17 July 2022 the two cases were confirmed by Ghana, [94] which caused the country to declare a Marburg virus disease outbreak. [95] An additional case was identified, bringing the total to three. [96]
A disease outbreak was first reported in Equatorial Guinea on 7 February 2023, and on 13 February 2023, it was identified as being Marburg virus disease. It was the first time the disease was detected in the country. [97] Neighbouring Cameroon detected two suspected cases of Marburg virus disease on 13 February 2023, [98] but they were later ruled out. [99] On 25 February, a suspected case of Marburg was reported in the Spanish city of Valencia, [100] however this case was subsequently discounted. [101] As of 4 April 2023, there were 14 confirmed cases and 28 suspected cases, including ten confirmed deaths from the disease in Equatorial Guinea. [102] [58] On 8 June 2023, the World Health Organization declared the outbreak over. [103] In total, 17 laboratory-confirmed cases and 12 deaths were recorded. All the 23 probable cases reportedly died. Four patients recovered from the virus and have been enrolled in a survivors programme to receive psychosocial and other post-recovery support. [104]
A Marburg virus disease outbreak in Tanzania was first reported on 21 March 2023 by the Ministry of Health of Tanzania. [105] This was the first time that Tanzania had reported an outbreak of the disease. On 2 June 2023, Tanzania declared the outbreak over. [106] There were 9 total infections, resulting in 6 total deaths. [60] [61]
Experimentally, recombinant vesicular stomatitis Indiana virus (VSIV) expressing the glycoprotein of MARV has been used successfully in nonhuman primate models as post-exposure prophylaxis. [107] A vaccine candidate has been effective in nonhuman primates. [108] Experimental therapeutic regimens relying on antisense technology have shown promise, with phosphorodiamidate morpholino oligomers (PMOs) targeting the MARV genome [109] New therapies from Sarepta [110] and Tekmira [111] have also been successfully used in humans as well as primates.
Filoviridae is a family of single-stranded negative-sense RNA viruses in the order Mononegavirales. Two members of the family that are commonly known are Ebola virus and Marburg virus. Both viruses, and some of their lesser known relatives, cause severe disease in humans and nonhuman primates in the form of viral hemorrhagic fevers.
The genus Marburgvirus is the taxonomic home of Marburg marburgvirus, whose members are the two known marburgviruses, Marburg virus (MARV) and Ravn virus (RAVV). Both viruses cause Marburg virus disease in humans and nonhuman primates, a form of viral hemorrhagic fever. Both are select agents, World Health Organization Risk Group 4 Pathogens, National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogens, Centers for Disease Control and Prevention Category A Bioterrorism Agents, and are listed as Biological Agents for Export Control by the Australia Group.
The genus Ebolavirus is a virological taxon included in the family Filoviridae, order Mononegavirales. The members of this genus are called ebolaviruses, and encode their genome in the form of single-stranded negative-sense RNA. The six known virus species are named for the region where each was originally identified: Bundibugyo ebolavirus, Reston ebolavirus, Sudan ebolavirus, Taï Forest ebolavirus, Zaire ebolavirus, and Bombali ebolavirus. The last is the most recent species to be named and was isolated from Angolan free-tailed bats in Sierra Leone. Each species of the genus Ebolavirus has one member virus, and four of these cause Ebola virus disease (EVD) in humans, a type of hemorrhagic fever having a very high case fatality rate. The Reston virus has caused EVD in other primates. Zaire ebolavirus has the highest mortality rate of the ebolaviruses and is responsible for the largest number of outbreaks of the six known species of the genus, including the 1976 Zaire outbreak and the outbreak with the most deaths (2014).
Viral hemorrhagic fevers (VHFs) are a diverse group of animal and human illnesses. VHFs may be caused by five distinct families of RNA viruses: the families Filoviridae, Flaviviridae, Rhabdoviridae, and several member families of the Bunyavirales order such as Arenaviridae, and Hantaviridae. All types of VHF are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases. Some of the VHF agents cause relatively mild illnesses, such as the Scandinavian nephropathia epidemica, while others, such as Ebola virus, can cause severe, life-threatening disease.
Crimean–Congo hemorrhagic fever (CCHF) is a viral disease. Symptoms of CCHF may include fever, muscle pains, headache, vomiting, diarrhea, and bleeding into the skin. Onset of symptoms is less than two weeks following exposure. Complications may include liver failure. Survivors generally recover around two weeks after onset.
Lisa Ellen Hensley is the associate director of science at the Office of the Chief Scientist, National Institute of Allergy and Infectious Disease Integrated Research Facility in Frederick, Maryland. She was previously a civilian microbiologist in the virology division of the United States Army Medical Research Institute of Infectious Diseases (USAMRIID). Hensley is one of the premier researchers of some of the world's most dangerous infections, including Ebola hemorrhagic fever, Lassa fever, the coronavirus diseases Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and smallpox. She has been involved in research uncovering critical mechanisms in the pathogenesis of hemorrhagic fever viruses, and has used those discoveries to develop candidate therapeutic drugs for their treatment.
The species Bundibugyo ebolavirus is the taxonomic home of one virus, Bundibugyo virus (BDBV), that forms filamentous virions and is closely related to the infamous Ebola virus (EBOV). The virus causes severe disease in humans in the form of viral hemorrhagic fever and is a Select agent, World Health Organization Risk Group 4 Pathogen, National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogen, Centers for Disease Control and Prevention Category A Bioterrorism Agent, and is listed as a Biological Agent for Export Control by the Australia Group.
The species Taï Forest ebolavirus is a virological taxon included in the genus Ebolavirus, family Filoviridae, order Mononegavirales. The species has a single virus member, Taï Forest virus (TAFV). The members of the species are called Taï Forest ebolaviruses.
The species Sudan ebolavirus is a virological taxon included in the genus Ebolavirus, family Filoviridae, order Mononegavirales. The species has a single virus member, Sudan virus (SUDV). The members of the species are called Sudan ebolaviruses. It was discovered in 1977 and causes Ebola clinically indistinguishable from the ebola Zaire strain, but is less transmissible than it. Unlike with ebola Zaire there is no vaccine available.
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 World Health Organization (WHO) rates it as a Risk Group 4 Pathogen. 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.
Ravn virus is a close relative of Marburg virus (MARV). RAVV causes Marburg virus disease in humans and nonhuman primates, a form of viral hemorrhagic fever. RAVV is a Select agent, World Health Organization Risk Group 4 Pathogen, National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogen, Centers for Disease Control and Prevention Category A Bioterrorism Agent, and listed as a Biological Agent for Export Control by the Australia Group.
Ebola, also known as Ebola virus disease (EVD) and Ebola hemorrhagic fever (EHF), is a viral hemorrhagic fever in humans and other primates, caused by ebolaviruses. Symptoms typically start anywhere between two days and three weeks after infection. The first symptoms are usually fever, sore throat, muscle pain, and headaches. These are usually followed by vomiting, diarrhoea, rash and decreased liver and kidney function, at which point some people begin to bleed both internally and externally. It kills between 25% and 90% of those infected – about 50% on average. Death is often due to shock from fluid loss, and typically occurs between six and 16 days after the first symptoms appear. Early treatment of symptoms increases the survival rate considerably compared to late start. An Ebola vaccine was approved by the US FDA in December 2019.
Zaire ebolavirus, more commonly known as Ebola virus, is one of six known species within the genus Ebolavirus. Four of the six known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals, known as Ebola virus disease (EVD). Ebola virus has caused the majority of human deaths from EVD, and was the cause of the 2013–2016 epidemic in western Africa, which resulted in at least 28,646 suspected cases and 11,323 confirmed deaths.
Recombinant vesicular stomatitis virus–Zaire Ebola virus (rVSV-ZEBOV), also known as Ebola Zaire vaccine live and sold under the brand name Ervebo, is an Ebola vaccine for adults that prevents Ebola caused by the Zaire ebolavirus. When used in ring vaccination, rVSV-ZEBOV has shown a high level of protection. Around half the people given the vaccine have mild to moderate adverse effects that include headache, fatigue, and muscle pain.
On 11 May 2017, the Democratic Republic of the Congo (DRC) was identified by the World Health Organization (WHO) as having one Ebola-related death.
The 2017 Uganda Marburg virus outbreak was confirmed by the World Health Organization (WHO) on 20 October 2017 after there had been an initial fatality due to the virus.
The 1967 Marburg virus disease outbreak was the first recorded outbreak of Marburg virus disease. It started in early August 1967 when 30 people became ill in the West German towns of Marburg and Frankfurt and later two in Belgrade, Yugoslavia. The infections were traced back to three laboratories in the separate locations which received a shared shipment of infected African green monkeys. The outbreak involved 25 primary Marburg virus infections and seven deaths, and six non-lethal secondary cases.
In August–November 1976, an outbreak of Ebola virus disease occurred in Zaire. The first recorded case was from Yambuku, a small village in Mongala District, 1,098 kilometres (682 mi) northeast of the capital city of Kinshasa.
On 7 February 2021, the Congolese health ministry announced that a new case of Ebola near Butembo, North Kivu had been detected the previous day. The case was a 42-year-old woman who had symptoms of Ebola in Biena on 1 February 2021. A few days after, she died in a hospital in Butembo. The WHO said that more than 70 people who had contact with the woman had been tracked.