What to Know About the Signs and Symptoms

Marburg virus disease is a “rare but severe hemorrhagic fever” caused by Marburg virus, according to the Centers for Disease Control and Prevention (CDC.) This RNA virus is a member of the filovirus family, which also includes the Ebola virus.

While both diseases are rare, they can cause outbreaks with high death rates.

In past outbreaks, case fatality rates for Marburg virus have varied from 24% to 88%, according to the WHO, depending on the virus strain and the quality of case management.

Marburg virus can be transmitted to people from infected African fruit bats or their urine and/or excretions. This can occur when workers or tourists enter mines inhabited by these bats.

The virus can spread between people through direct contact with the blood, secretions, organs or other bodily fluids of infected people, as well as from contaminated surfaces and materials.

Healthcare workers and relatives of infected patients are at risk if strict infection control precautions are not taken. Direct contact with the body of the deceased can also contribute to transmission of the virus.

The first known outbreaks of Marburg virus disease occurred in 1967 in Marburg and Frankfurt in Germany; and in Belgrade, Serbia. These outbreaks were associated with laboratory work using African green monkeys imported from Uganda.

Illness caused by Marburg virus can occur “abruptly,” according to the WHO, with high fever, severe headache and severe malaise.

Other common symptoms include muscle aches and pains, abdominal pain and cramping, nausea, vomiting and diarrhea.

During this phase, patients have a “ghost-like” appearance, says the WHO, with drawn features, deep-set eyes, expressionless faces and extreme lethargy.

In fatal cases, death usually occurs between eight and nine days after the start of symptoms. This is usually preceded by severe loss of blood and resulting damage to multiple organs.

No vaccines or antiviral therapies have been approved to treat Marburg virus disease.

Supportive care — such as rehydrating with oral or intravenous fluids, and maintaining oxygen levels — and treating specific symptoms can help improve survival rates, says the WHO.

The WHO says monoclonal antibodies being developed or antivirals that have been used in clinical trials for Ebola virus disease could also potentially be tested for Marburg virus disease.

In addition, “there are several experimental treatments that have been shown to protect animals against lethal Marburg virus infection,” said Thomas Geisbert, PhD, a professor in the Department of Microbiology and Immunology at the University of Texas Medical Branch in Galveston.

This includes a monoclonal antibody from Mapp Biopharmaceutical, Inc., and Gilead Sciences, Inc.’s antiviral remdesivir.

“Remdesivir is currently approved for human use for treating COVID-19,” said Geisbert, “and the possible off-label use for Marburg is probably the most realistic and quickest intervention that could be deployed.”

The WHO held a meeting on Tuesday to discuss vaccines and therapies that could be tested against Marburg.

Erica Ollmann Saphire, PhD, a professor of the La Jolla Institute for Immunology, says all outbreaks of Marburg and Ebola viruses are concerning.

“The greatest threat occurs when the outbreaks are in areas with dense populations, a lot of movement of people and a greater interaction with the natural world,” she said.

For example, “the Ebola outbreak in 2014-2016 grew large because it spilled over into urban centers where there was a lot of human movement across borders,” she said.

However, “with only one confirmed case [in the current Marburg outbreak], it is too early to predict whether the outbreak will be small like the two cases in Ghana last year, or larger like the outbreak of 374 cases in Angola in 2004-2005,” said Geisbert.

The best option to “break the train of transmission” is contact tracing and medical management of the cases, he said.

In addition, “there are some vaccines that could potentially be used in a ring vaccination approach,” he noted.

This approach was used during the 2013-2016 Ebola epidemic in West Africa. It involves vaccinating the people at highest risk of infection, based on their connection to someone with a confirmed infection.

Saphire said probably the most surprising aspect of this is that Equatorial Guinea has not had an outbreak of Marburg virus disease before.

But in other ways, the appearance of the virus now is not that surprising.

“These viruses are out there, lurking in the forests, sometimes without known spillovers into humans,” she said. “As climate changes and people encroach more on wild areas, emergence of viruses and re-emergence of viruses is sort of inevitable.”

Given this ongoing threat, what’s needed, she said, is continued efforts to develop vaccines for different kinds of viruses.

Effective treatments are also needed, she added, because some people will get infected before health officials can get vaccines to them, or there will be breakthrough cases among people already vaccinated.

“The world is teeming with different viruses, and they spill over frequently [into humans], and will continue to do so,” she said.