Ebola-Related Marburg Virus Outbreak in Africa | What is the Marburg Disease?
Causing several outbreaks on the African continent in recent years, the deadly Marburg Virus (MARV) has now surfaced for the first time in Equatorial Guinea and Cameroon. The outbreak was initially detected on February 7 among patients presenting with fever, fatigue, bloodstained vomit, and diarrhea. After the Institut Pasteur reference laboratory in Senegal found one MDV-positive sample among the eight tested samples, the Ministry of Health and Social Welfare (MoH) of Equatorial Guinea confirmed a Marburg virus disease (MVD) outbreak on 13 February 2023. According to the World Health Organization, Equatorial Guinea has reported nine deaths and sixteen suspected cases of Marburg Virus Disease (MVD), whereas Cameroon has reported an additional two suspected cases. Despite the geographical proximity of Cameroon and Equatorial Guinea’s affected areas, both instances detected in Cameroon have yet to be found to have a travel history, which may suggest an ongoing local transmission in both countries. The exact source of the outbreak remains unclear, and genome sequencing efforts are continuing. Read along to learn more about the deadly Marburg Virus Disease (MVD), its transmission, symptoms, and diagnosis.
What is Marburg Virus Disease (MVD)?
Marburg virus disease (MVD) is a viral hemorrhagic fever caused by the Marburg virus (MARV) from the family Filoviridae. The family Filoviridae also includes six species of Ebola viruses. Marburg virus (MARV) is a zoonotic, enveloped, filamentous, negative single-stranded RNA virus. It affects various cells, tissues, and organs in humans and non-human primates. The virus has been observed to target macrophages and dendritic cells at the cellular level and lymphoid tissues and the liver at the organ level. Although case fatality rates associated with the Marburg virus (MARV) have ranged from 24% to 88% depending on the responsible virus strain, access to medical care, and overall success of case management, the World Health Organization reports that the average case fatality rate for the disease is approximately 50%. Given its high case fatality rate, Marburg virus (MARV) has been classified as a Risk Group 4 pathogen, which refers to pathogens that often cause severe human and animal disease, spread from person to person, and lack effective treatment.
The primary reservoir of the Marburg virus disease is thought to be the African fruit bat. Since the African fruit bat is widely distributed across Africa, the Marburg virus disease most often occurs in Africa. Following its initial discovery in researchers in Germany and the former Yugoslavia working with samples from African green monkeys imported from Uganda in 1967, Marburg virus (MARV) has caused sporadic cases and outbreaks in South Africa (1975), Kenya (1980/1987), former Soviet Union (1988/1990), Democratic Republic of Congo (1998-2000), Angola (2004-2005), Netherlands (2008), United States (2008), Uganda (2007/2008/2012/2014/2017), Guinea (2021), and Ghana (2022). Although occasional cases have been detected elsewhere in patients returning from Africa, Marburg virus (MARV) outbreaks have primarily affected workers in bat-infested mines in Africa.
How is Marburg Virus (MARV) transmitted?
Animal-to-human transmission of the Marburg virus (MARV) is possible through direct exposure to Egyptian fruit bats. Transmission among humans, on the other hand, may involve direct contact with infected people’s blood, secretions, organs, and other bodily fluids or with recently contaminated surfaces and objects. Although no such case has been observed, transmission through transfusion and transplantation has also been suspected.
What are the Signs and Symptoms of Marburg Virus Disease (MVD)?
Marburg virus disease (MVD) symptoms often present with a sudden onset after an incubation period of 2 to 21 days. Its initial symptoms include fever, chills, headaches, muscle pain, and joint aches. As the disease progresses, a raised rash and more severe symptoms such as abdominal pain, nausea, vomiting, sore throat, chest pain, bruising, and ocular bleeding may develop. If left untreated, the infection reaches a critical state that causes severe damage to many organs, including the liver, pancreas, and kidneys. This phase of the disease may present with symptoms and complications such as severe bleeding from the eyes, ears, nose, or rectum, extreme weight loss, jaundice, delirium, shock, and multi-organ dysfunction, which may develop into multi-organ failure, dementia, coma, seizures, or internal bleeding.
How is Marburg Virus Disease (MVD) diagnosed?
As the signs and symptoms of Marburg virus disease can be similar to various conditions such as malaria, typhoid fever, dengue fever, and Ebola virus disease, its clinical diagnosis may be prone to challenges or delays. Fortunately, several testing options, such as reverse transcription-polymerase chain reaction (RT-PCR) tests, antigen tests, and serological tests, can assist in diagnosing Marburg virus disease throughout different stages of infection. Tests employing molecular methods, such as reverse transcription-polymerase chain reaction (RT-PCR), offer high sensitivity and specificity in diagnosing Marburg virus disease (MVD). In addition, assays targeting the strain-specific GP gene have been widely used to determine the responsible strains. Antigen testing, however, is most accurate in the early stages of Marburg virus disease (MVD) when the viral load in blood and tissues peak. Finally, serological detection methods targeting the IgM and IgG antibodies against Marburg virus disease (MVD) have been used respectively to detect recent and past infections with the Marburg virus (MAV).
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