Marburgvirus

Marburgvirus is a genus of viruses in the family Filoviridae, which also includes the genus Ebolavirus. Marburgvirus was the first filovirus to be identified and causes Marburg virus disease in humans and nonhuman primates, a form of viral hemorrhagic fever that is highly lethal. The virus is named after Marburg, the city in Germany where it was first discovered in 1967 during an outbreak among laboratory workers who were exposed to infected green monkeys imported from Uganda.

Structure and Genome

Marburgvirus is characterized by its filamentous structure, which can vary in shape from straight to curved, forming loops or "U" or "6" shapes. The virus particles are approximately 80 nm in diameter and can be up to several micrometers in length. The genome of Marburgvirus is a single-stranded, negative-sense RNA approximately 19 kb in length. It encodes seven structural and nonstructural proteins, including the nucleoprotein (NP), glycoprotein (GP), polymerase (L), and several viral proteins (VP35, VP40, VP30, and VP24) that are involved in virus replication and immune evasion.

Transmission and Epidemiology

Marburgvirus is zoonotic, meaning it is transmitted to humans from animals. The natural reservoir host of Marburgvirus is believed to be the Egyptian fruit bat (Rousettus aegyptiacus), which can harbor the virus without showing symptoms. Human infections have been associated with direct contact with infected bats, or indirectly through contact with surfaces or materials contaminated with bat feces or saliva. Secondary transmission between humans can occur through direct contact with the blood, secretions, organs, or other bodily fluids of infected persons, or through contact with contaminated surfaces and materials.

Outbreaks of Marburg virus disease have been primarily reported in Africa, with significant outbreaks in Angola, the Democratic Republic of the Congo, Kenya, and Uganda. The case fatality rates of these outbreaks have varied but can be as high as 88%.

Clinical Features and Diagnosis

Marburg virus disease presents initially with nonspecific symptoms such as fever, chills, headache, and myalgia, making early diagnosis challenging. As the disease progresses, patients may develop severe hemorrhagic manifestations, including bleeding from the gums, nose, and gastrointestinal tract, which can lead to multi-organ failure and death.

Diagnosis of Marburg virus disease is confirmed through laboratory tests, including polymerase chain reaction (PCR) to detect viral RNA, enzyme-linked immunosorbent assay (ELISA) to detect viral antigens, and serology to detect antibodies against the virus.

Treatment and Prevention

There is no specific antiviral treatment approved for Marburg virus disease. Management of the disease is supportive and includes rehydration, pain management, and treatment of specific symptoms as they arise. Experimental treatments, including antiviral drugs and immunotherapies, are under investigation.

Prevention of Marburg virus disease focuses on avoiding contact with the natural reservoir (bats) and implementing strict infection control measures in healthcare settings to prevent person-to-person transmission. Public health measures, including surveillance, rapid identification and isolation of cases, contact tracing, and community education, are critical to controlling outbreaks.

See Also

• Viral hemorrhagic fever
• Ebolavirus
• Zoonosis