Q&A: Deadly Marburg virus causes second outbreak in West Africa
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On July 17, officials announced the first ever Marburg virus outbreak in Ghana, marking just the second time the virus has been detected in West Africa.
At the time of the announcement, there were two unrelated fatal cases in southern Ghana — a 26-year-old man who checked into a hospital on June 26 and died on June 27, and a 51-year-old man who reported to the hospital on June 28 and died on the same day.
In all, 108 contacts of the two cases self-quarantined and were monitored for symptoms, according to WHO. As of July 22, all had completed their 21-day follow-up without testing positive.
“Health authorities have responded swiftly, getting a head start preparing for a possible outbreak,” Matshidiso Moeti, MD, MPH, WHO’s Regional Director for Africa, said in a press release. “This is good because without immediate and decisive action, Marburg can easily get out of hand.”
The only other time Marburg virus has been detected in West Africa was in Guinea last year. That outbreak included just one reported case and was declared over on Sept. 16 — 42 days after the patient was buried. It came after researchers reported in 2020 that they had found the virus in West African bats for the first time.
According to WHO, previous outbreaks and cases of Marburg in Africa have been reported in Angola, the Democratic Republic of the Congo, Kenya, South Africa and Uganda.
We spoke with Tracey Goldstein, PhD, chief of the Emerging Threats Division at the U.S. Agency for International Development (USAID), about the danger of Marburg virus and its potential to spread. Goldstein’s team is supporting the outbreak response in Ghana.
Healio: You were part of the team that first identified Marburg virus in West African bats, a finding that was reported in a study in 2020. Last year, officials confirmed the first ever reported case of Marburg virus in West Africa in a patient in Guinea. Now there are at least two cases in Ghana. Are these likely to have been the first three cases in West Africa, or is it possible that there had been cases before the discovery of the virus in bats?
Goldstein: Yes, I do think it's possible that there were missed cases. We learned with Ebola, which is obviously a relative of Marburg, that there are sometimes milder disease that may not lead to patients seeking care and being tested. So, this is possible that that has happened.
The other thing is we don't currently have routine surveillance for Marburg virus in all of these countries, so it's difficult to know if cases are always occurring. Unless there's a reason to test with the virus, people don't just sort of generally screen for them. So, unless somebody is ill and seeking care, we won't always know what the background of infections are. I think that the importance of these findings highlighted that there were areas where there's risk for infection. So now when people come, we know to add that on the list to test for.
Healio: Does Marburg virus have pandemic potential?
Goldstein: That's a really interesting question, especially after what we saw with Ebola in West Africa. Generally, Marburg is a highly infectious viral hemorrhagic fever virus and so what that means is that it's usually transmitted through direct contact with bodily fluids. Usually, the initial spillover is thought to come from contact with Egyptian fruit bats and that's usually through contact in caves, but then it spreads from human to human through direct contact with bodily fluids of infected people or infected surfaces and materials. Because of that, it doesn't have that same pandemic potential as say, a respiratory virus, where you don't even have to have direct contact for the virus to spread. Although Marburg has a really high case fatality rate — up to 80% sometimes — it's not as transmissible as infections like influenza and COVID-19.
You never want to say never because what we've seen in the last few years is you can never rule out the possibility, but it's definitely less likely to cause a pandemic than a respiratory virus.
Healio: What is the potential for local and regional spread?
Goldstein: I think local and regional spread is definitely a key concern. People, especially in parts of West Africa, have a lot of high mobility — traveling across borders and between countries often for work, and we’ve seen that in outbreaks of Ebola in eastern Democratic Republic of the Congo. So, I think that there is the definite potential for regional and then also local spread. This is why early recognition of disease in our communities is so important — so that they can recognize signs of something changing or new signs of illness and be able to report that.
Healio: What local recommendations were made after the discovery of Marburg virus in West African bats, and are they being followed?
Goldstein: The critical information from that finding was that we have to stop thinking about where viruses were seen and where risk was in the past. We learned that there was risk where these animals that may carry the virus live. This was a joint finding through the USAID and the CDC. It allowed us to work with public health authorities in West Africa, so that Marburg virus could be added into surveillance plans, so that labs could be able to test for the virus, and so that clinicians were informed of the differential diagnosis to add that into the list for rapid identification and work in communities to make sure that they recognize signs of illness. All of those were implemented in various ways and in different countries, and not just in Sierra Leone, but in West Africa — we saw that in Guinea and in Liberia, for example. That allows doctors to quickly recognize signs and increase those responses. We saw that in the Guinea outbreak and right now, in the outbreak in Ghana, where there's been much quicker detection, much quicker response in terms of things like contact tracing, performing safe and dignified burials, quarantining people and then also implementing risk and reducing messages in community.
Healio: Recent Ebola virus outbreaks have been brought under control with the help of vaccination campaigns. Unlike Ebola, there are no vaccines or antiviral treatments for Marburg virus, although WHO noted that several phase 1 trials have been completed. Should the world make this a priority?
Goldstein: There's a number of things that can be done — like the fact that the there are some vaccines that have been in phase 1 trials. I do think it's important to invest further so we can actually take these items through to completion to where they're actually available for use.
One of the other things that can be done and that is being discussed right now is being able to test various vaccines and medicines that have been developed for Ebola virus against other viruses, like Marburg. Although a vaccine against Ebola or an antiviral against Ebola might not be perfect, does it provide some protection against Marburg virus? Can it be used in a situation where you don't have specific medicines and vaccines available?
I think it's also critical to invest in the development of broadly protective antivirals and vaccines. This has been a big discussion with COVID-19. Can we develop broader vaccines, not just against one variant or one type of virus? This really applies to the field of viruses. So, the Ebola and Marburg viruses, if you have something that's more broadly protective ... and you're not starting to scramble during that outbreak, you have something on the shelf. It might not be perfect, but hopefully it will provide some protection.
References:
Amman BR, et al. Nat Commun. 2020;doi:10.1038/s41467-020-14327-8.
Ghana declares first-ever outbreak of Marburg virus disease. https://www.afro.who.int/countries/ghana/news/ghana-declares-first-ever-outbreak-marburg-virus-disease-0. Posted July 17, 2022. Accessed July 25, 2022.
WHO. Marburg virus disease – Guinea. https://www.who.int/emergencies/disease-outbreak-news/item/marburg-virus-disease---guinea. Published Sept. 17, 2021. Accessed July 26, 2022.
WHO. Marburg virus – Ghana. https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON402. Published July 22, 2022. Accessed July 26, 2022.
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Healio Interview
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