| 2021 Marburg virus disease outbreak in Guinea | |
|---|---|
 Colorized Marburg virus particles | |
| Disease | Marburg virus |
| Source | Egyptian Rousette bats |
| Location | Guinea |
| Date | 25 July 2021 - 16 September 2021 |
| Confirmed cases | 1 |
Deaths | 1 |
| Fatality rate | 24-90% |
| Vaccinations | N/A |
The outbreak of Marburg virus disease in Gueckedou district, Guinea started in July 2021, and ended in September. A single individual got sick and died of the virus, with no other known cases. [1]
Marburg virus disease is a highly virulent, epidemic-prone disease, associated with a high case-fatality ratio of 24-90%. In the early phase of the disease, it is hard to distinguish the disease from other diseases. There are no specific treatments or vaccine against the Marburg virus, though supportive care increases the likelihood of survival. [2] 14 outbreaks of the disease have been reported since 1967, when it was first detected, mostly in sub-Saharan Africa. [3]
The disease's usual reservoir species is Egyptian Rousette bats. [4] Among humans, it is transmitted via direct contact with the bodily fluids of an infected individual. [5] Guéckédou, the site of the outbreak, had recently had an Ebola outbreak, as well as the ongoing COVID-19 pandemic.[ citation needed ]
The index case, a 46-year-old farmer from Temessadou M’Boké village in Guéckédou prefecture, got his first symptoms on July 25. [6] The patient died on August 2. On August 3, a Polymerase Chain Reaction (PCR) test was conducted, returning a positive result for the Marburg virus on August 5. The WHO was informed of the first case the next day. On August 9, the Institut Pasteur Dakar in Senegal provided reconfirmation that the result was positive for the Marburg virus. [6] Sequencing of an isolate from the Guinean patient showed that this outbreak was caused by the Angola-like Marburg virus. [6]
Guinea health authorities conducted contact tracing and monitored 170 known high-risk contacts of the index case. No new cases were detected for twice the length of the incubation period of the virus, in this case 42 day, so the outbreak was declared over around six weeks after it started. [2] [1]
WHO's Africa director Matshidiso Moeti, among others, praised Guinea's rapid and effective response to the outbreak. [7]
A team of WHO specialists arrived in Temessadou M’bokét in August–September 2021 for an epidemiological investigation of the case and searched for the Marburg virus reservoir. [8] The team conducted bat trapping in the immediate vicinity of the village of Temessadou M’bokét, as well as in the vicinity of neighboring villages (Baladou Pebal and Koundou). [8]
The patient had limited social interactions and lived in a household of four people. [6] There was no evidence of a travel history outside Guinea for the patient or his close contacts or of contact with returning travelers. He was a farmer living in close contact with nature and wildlife and may therefore have had repeated exposure to an environment or food contaminated with excreta of MARV-infected bats. Community surveys showed that although he may have harvested wild fruits for personal consumption, there was no suggestion that he had visited caves or been involved in hunting activities for bushmeat, including bats. [6]
Previously, in 2017–2018, Marburg virus was detected in the Egyptian rousette bats (Rousettus aegyptiacus) in the neighboring Sierra Leone. [9] This was the first detection of Marburg virus in West Africa. Phylogenetic analysis revealed that at least two genetic variants of Marburg virus circulate in bats in Sierra Leone: Angola-like Marburg virus and Marburg virus, which are genetically similar to variants from Uganda, Gabon, and the Democratic Republic of Congo (DRC). [9] The presence of Marburg virus in the fruit bats in Guinea was confirmed in 2022: a colony of Egyptian rousettus bats with infected animals was found in close proximity (4.5 km) to the Temessadou M’bokét village. [10] Marburg virus isolated from these animals belonged to the Angola-like lineage [10] as well as the isolate obtained from the index-case patient. [6]
Marburg virus disease 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). Its clinical symptoms are very similar to those of Ebola virus disease (EVD).
Megabats constitute the family Pteropodidae of the order Chiroptera (bats). They are also called fruit bats, Old World fruit bats, or—especially the genera Acerodon and Pteropus—flying foxes. They are the only member of the superfamily Pteropodoidea, which is one of two superfamilies in the suborder Yinpterochiroptera. Internal divisions of Pteropodidae have varied since subfamilies were first proposed in 1917. From three subfamilies in the 1917 classification, six are now recognized, along with various tribes. As of 2018, 197 species of megabat had been described.
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.
The Egyptian fruit bat or Egyptian rousette is a species of megabat that is found in Africa, the Middle East, the Mediterranean, and the Indian subcontinent. It is one of three Rousettus species with an African-Malagasy range, though the only species of its genus found on continental Africa. The common ancestor of the three species colonized the region in the late Pliocene or early Pleistocene. The species is traditionally divided into six subspecies. It is considered a medium-sized megabat, with adults weighing 80–170 g (2.8–6.0 oz) and possessing wingspans of approximately 60 cm (24 in). Individuals are dark brown or grayish brown, with their undersides paler than their backs.
The Madagascan rousette or Madagascar rousette, is a species of megabat in the family Pteropodidae endemic to Madagascar. Its natural habitat is subtropical or tropical dry forests.
Lujo is a bisegmented RNA virus—a member of the family Arenaviridae—and a known cause of viral hemorrhagic fever (VHF) in humans. Its name was suggested by the Special Pathogens Unit of the National Institute for Communicable Diseases of the National Health Laboratory Service (NICD-NHLS) by using the first two letters of the names of the cities involved in the 2008 outbreak of the disease, Lusaka (Zambia) and Johannesburg. It is the second pathogenic Arenavirus to be described from the African continent—the first being Lassa virus—and since 2012 has been classed as a "Select Agent" under U.S. law.
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. 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.
Usutu virus (USUV) is a flavivirus belonging to the Japanese encephalitis complex, which is an emerging zoonotic arbovirus of concern because of its pathogenicity to humans and its similarity in ecology with other emerging arboviruses such as West Nile virus. It mainly infects Culex mosquitoes and birds; humans form a dead-end host. First identified in South Africa in 1959, the virus has caused outbreaks in birds across Europe since 1996. Nearly 50 cases in humans have been reported as of 2019, mainly in Europe. These are predominantly asymptomatic, but some people experience neurological symptoms.
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.
Favipiravir, sold under the brand name Avigan among others, is an antiviral medication used to treat influenza in Japan. It is also being studied to treat a number of other viral infections, including SARS-CoV-2. Like the experimental antiviral drugs T-1105 and T-1106, it is a pyrazinecarboxamide derivative.
The bat virome is the group of viruses associated with bats. Bats host a diverse array of viruses, including all seven types described by the Baltimore classification system: (I) double-stranded DNA viruses; (II) single-stranded DNA viruses; (III) double-stranded RNA viruses; (IV) positive-sense single-stranded RNA viruses; (V) negative-sense single-stranded RNA viruses; (VI) positive-sense single-stranded RNA viruses that replicate through a DNA intermediate; and (VII) double-stranded DNA viruses that replicate through a single-stranded RNA intermediate. The greatest share of bat-associated viruses identified as of 2020 are of type IV, in the family Coronaviridae.
The 2013–2016 epidemic of Ebola virus disease, centered in Western Africa, was the most widespread outbreak of the disease in history. It caused major loss of life and socioeconomic disruption in the region, mainly in Guinea, Liberia and Sierra Leone. The first cases were recorded in Guinea in December 2013; later, the disease spread to neighbouring Liberia and Sierra Leone, with minor outbreaks occurring in Nigeria and Mali. Secondary infections of medical workers occurred in the United States and Spain. In addition, isolated cases were recorded in Senegal, the United Kingdom and Italy. The number of cases peaked in October 2014 and then began to decline gradually, following the commitment of substantial international resources.
Meliandou is a village in Guéckédou Prefecture, in the Nzérékoré Region of southern Guinea. Medical researchers believe that the village was the location of the first known case of Ebola virus disease in the epidemic in West Africa. The patient zero of Ebola was a two-year-old boy who died in 2013. The boy's pregnant mother, sister, and grandmother also became ill with symptoms consistent with Ebola infection and died. People infected by those victims later spread the disease to other villages.
An epidemic of Ebola virus disease in Guinea from 2013 to 2016 represents the first ever outbreak of Ebola in a West African country. Previous outbreaks have been confined to several countries in Sub-Saharan Africa.
Bombali ebolavirus or Bombali virus (BOMV) is a species of the genus Ebolavirus, first reported on 27 July 2018. It was discovered and sequenced by a PREDICT research team from the U.S. in the Bombali area in the north of Sierra Leone, west Africa. The virus was found in the Angolan free-tailed bat and the Little free-tailed bat.
A Nipah virus infection is a viral infection caused by the Nipah virus. Symptoms from infection vary from none to fever, cough, headache, shortness of breath, and confusion. This may worsen into a coma over a day or two, and 50 to 75% of those infected die. Complications can include inflammation of the brain and seizures following recovery.
The 1967 Marburg virus 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 July 2022, an outbreak of Marburg virus disease occurred in Ghana. Two positive cases were reported by Ghana on 8 July. After confirmation by the World Health Organization, it is the first such outbreak in Ghana. Two men aged 26 and 51 years old were infected with the disease and both cases resulted in fatalities. An additional case was identified, bringing the total to three.
| Ebolavirus |
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| Marburgvirus |
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| Cuevavirus |
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| Dianlovirus |
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| Striavirus |
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| Thamnovirus |
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