Analysis | Why Marburg Virus Is an Increasing Threat in Africa


Marburg virus killed two men in Ghana in June, touching off the West African nation’s first confirmed outbreak of the highly virulent disease. From the same family as the Ebola virus, Marburg caused occasional outbreaks and sporadic cases mostly in Central and Southern Africa until Guinea, in West Africa, confirmed a single, lethal case in August 2021. The latest deaths show once again how a pathogen found in fruit bats can cross the species barrier to infect humans and risk touching off a deadly scourge.

1. What is Marburg virus?

It’s a member of the Filoviridae family of viruses which can cause severe hemorrhagic fever in people, killing up to 90% of those infected. Marburg virus disease was recognized in 1967, when outbreaks occurred simultaneously in laboratories in Marburg and Frankfurt, both in Germany, and in the Serbian capital, Belgrade. Cases were traced to green monkeys imported from Uganda for research and polio vaccine production. Nine years later, a closely related virus was found to have sparked a deadly outbreak in a village near the Ebola River in Congo, giving that virus its name. Since then, many more viruses known to cause similar diseases in humans have been discovered around the world, with globalization, international travel, and climate change aiding their spread.

2. What symptoms does it cause?

After an incubation period of two to 21 days, symptoms begin with a high fever, severe headache and severe malaise, often accompanied by muscle aches and pains. Watery diarrhea, abdominal pain and cramping, nausea and vomiting can begin on the third day. Diarrhea can persist for a week. The appearance of patients at this phase has been described as showing “ghost-like,” drawn features, deep-set eyes, expressionless faces and extreme lethargy. In the first recorded outbreak in 1967, a non-itchy rash was noted in most patients two-to-seven days after the onset of symptoms. Many patients develop severe bleeding, or hemorrhaging, at the end of the first week of symptoms. Fresh blood in vomit and feces is often accompanied by bleeding from the nose, gums, and vagina. Spontaneous bleeding at sites where intravenous access is obtained to give fluids or obtain blood samples can be particularly troublesome. During the severe phase of illness, patients have sustained high fevers. Involvement of the central nervous system can result in confusion, irritability, and aggression. Males occasionally experience inflammation of one or both testicles in the third week of the disease. In fatal cases, death occurs most often eight to nine days after symptom onset, usually preceded by severe blood loss and shock.

Without diagnostic lab tests, it can be difficult to distinguish Marburg virus disease from malaria, typhoid fever, shigellosis and meningitis or Ebola, Lassa fever and other viral hemorrhagic diseases. Samples collected from patients are an extreme biohazard risk. The World Health Organization recommends conducting tests under maximum biological containment conditions with specimens transported using a triple packaging system.

4. How do outbreaks start?

The African fruit bat Rousettus aegyptiacus is considered the reservoir host, or main carrier, of Marburg virus. Human cases have resulted from prolonged exposure to mines or caves inhabited by colonies of the flying mammals. Primates, such as monkeys and apes, can also be infected. Encroachment into forested areas and direct interaction with wildlife, such as “bush meat” consumption, facilitate the spread of Marburg and other filoviruses from animals to humans. Once a person is infected, the pathogen can be transmitted from person to person via direct contact through broken skin or mucous membranes with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials, such as bedding and clothing, contaminated with these fluids.

Historically, the people at highest risk include family members and hospital staff who care for patients infected with Marburg virus and haven’t used personal protective equipment or other infection prevention measures. Veterinarians and laboratory or quarantine facility workers who handle non-human primates from Africa may also be at increased risk of exposure. Burial ceremonies that involve direct contact with the body of the deceased can also contribute in the transmission of Marburg.

6. Are there treatments and vaccines? 

No vaccine or antiviral treatment has been approved for Marburg virus disease, though several approaches, including blood products, immune therapies, monoclonal antibodies and antivirals, are being evaluated, according to the WHO. Supportive care, especially rehydration with oral or intravenous fluids, and treatment of specific symptoms improves chances of survival. The US government’s Biomedical Advanced Research and Development Authority provided additional funding in October to the Sabin Vaccine Institute and New York-based IAVI to advance mid-stage clinical trials on candidate vaccines.

7. How is the current outbreak being managed?

Both cases occurred in Ghana’s Ashanti region, known for its gold and cocoa production. The first was a 26-year-old male who checked into a hospital on June 26 and died the following day. The second was a 51-year-old male who reported to the same hospital on June 28 and died that day. WHO is supporting health authorities in a joint investigation in the southern region, it said in a July 17 statement. The UN agency is deploying experts, making PPE available, bolstering surveillance, testing, tracing contacts, working with communities to alert and educate them about the risks and dangers and collaborating with emergency response teams. More than 90 contacts, including health workers and community members, have been identified and are being monitored, the WHO statement said.

8. Where else have cases occurred?

Since the initial cases among lab workers in Germany and former Yugoslavia in 1967, outbreaks have occurred in Zimbabwe, Kenya, Congo, Angola, Uganda and Guinea. A fatal case occurred in Russia in 1990 after a lab infection, and another in 2008 in a woman who had returned home to the Netherlands after visiting the Python Cave in Uganda’s Maramagambo Forest days earlier. 

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