Scanning electron micrograph of Marburg virus particles
NIAID
Rwanda is facing its first-ever Marburg virus outbreak. Starting in late September, by October 17, 62 cases and 15 deaths had been reported, most among health workers in the capital, Kigali.
More than 800 contacts of infected people are being traced to detect infections early and prevent further infections, two of whom had traveled to Belgium and Germany, and are considered normal. . As of October 21, no new infections or deaths have been reported for six days, but the threat of further infection remains.
What is Marburg virus and what are its symptoms?
Marburg virus belongs to the same family of viruses as the virus that causes Ebola and is “one of the most lethal pathogens known to infect humans,” the journal Perspective states. There is. New England Medical Journal.
In addition to muscle aches and pains, it can cause similar symptoms such as fever, chills, and headache. Within a few days, a rash may appear on the chest, back, and abdomen. You may also experience nausea, vomiting, and diarrhea.
Marburg virus damages blood vessels and breaks down clotting, so you may see blood in your vomit or stool, or bleeding from your nose or gums. In extreme cases, the infection can cause internal bleeding and sepsis, which can lead to organ failure and death.
Where do outbreaks typically occur?
The virus was first identified in 1967 after one-off outbreaks in the German cities of Marburg and Frankfurt and the Serbian capital, Belgrade. These cases were associated with laboratory experiments to improve polio vaccines for African green monkeys (Chlorocebus aethiopus) From Uganda.
Since then, the virus has typically caused several outbreaks every decade, mostly in East African countries such as Uganda and neighboring Democratic Republic of the Congo (DRC) in Central Africa.
The virus was identified in Guinea, West Africa, in 2021. Since then, outbreaks have occurred annually in different parts of the African continent. For example, Ghana had its first outbreak in 2022, and Equatorial Guinea had its first case last year. Egyptian fruit bat (Aedes aegypti) are found in various parts of Africa and can transmit the Marburg virus, said Emma Thomson from the University of Glasgow in the UK.
The exact reason why outbreaks seem to be occurring more frequently is unknown. Thomson said this could be due to improved case surveillance and people coming into more regular contact with Egyptian free-tailed bats. Miles Carroll of Oxford University thinks the same way.
If you visit caves where bats live or work in mines, you can become infected with Marburg virus. Things may be getting worse, Carroll said, but increased deforestation is also bringing people closer to these animals.
How deadly is it?
The mortality rate for Marburg virus has varied widely in past outbreaks, ranging from 24% to 88%, similar to Ebola’s mortality rate of 25% to 90%.
The range in mortality rates is likely due to differences in each country’s ability to detect cases and hospital resources, Thomson said.
On October 20, World Health Organization Director-General Tedros Adhanom Ghebreyesus issued a statement saying the organization was impressed by the level of critical care people are receiving in Rwanda. He mentioned two patients who had multiple organ failure and were on life support and on ventilators. “We believe this is the first time a Marburg virus patient has been extubated in Africa,” he said. “These patients would have died in previous outbreaks.”
Rwanda’s ongoing outbreak is the third largest on record, both in terms of cases and deaths. This is similar to the 1998-2000 outbreak in the Democratic Republic of the Congo, where 154 people were infected and 128 people died, and the 2004-2005 outbreak in Angola, where 252 people were infected and 227 people died. Happening after death.
Who is most at risk?
Since Marburg virus was identified, there have been relatively few known cases, making it difficult to know who is most at risk of severe infection, Thomson said. But people with suppressed immune systems, such as the elderly and pregnant people, are likely more vulnerable, she says.
Few cases have been reported during pregnancy, but the European Center for Disease Prevention and Control says infections are generally more severe during pregnancy, when immune systems change anyway.
Thomson said the same is probably true for Marburg virus, as Ebola is more likely to be severe in older people.
How do you catch it?
Genetic sequencing of cases in Rwanda revealed that the virus jumped from animals such as Egyptian free-tailed bats and African green monkeys to humans just once in an ongoing outbreak, the country’s health minister said in October. Tweeted on the 20th.
Therefore, the remaining infections occurred between people. This can occur when virus particles in someone’s blood or other body fluids enter another person’s body through broken skin, eyes, nose, or mouth. Burial rituals that involve touching the bodies of infected people also increase the risk of infection.
Carroll said there is no evidence that the Marburg virus is spread through droplets expelled when an infected person breathes, talks, coughs or sneezes.
How will I be treated?
There are no drugs approved to specifically treat Marburg virus. People who require hospital treatment are usually given intravenous fluids to replace fluids lost through vomiting and diarrhea. Painkillers can also help relieve discomfort.
In 2021, researchers discovered that combining the antiviral drug remdesivir with antibodies against the virus protected four out of five rhesus macaques from a lethal dose of infection. On October 15, Rwanda began clinical trials of this approach.
Is there a vaccine?
There is no approved vaccine for Marburg virus, but researchers are trialling an experimental vaccine in Rwanda, with 1,700 doses distributed and 669 doses administered as of October 14.
This vaccine regimen consists of a single shot containing an engineered adenovirus genetic sequence that causes cold-like symptoms. The researchers tweaked the adenovirus to incorporate proteins that Marburg virus uses to infect cells. Once injected, adenoviruses enter cells and produce copies of viral proteins so the immune system can recognize them.
Thomson said vaccinating contacts of infected people will likely be the most efficient use of vaccine doses to slow the spread of the virus.
What is the risk of this epidemic leaving Rwanda?
Although Rwanda has ramped up testing of contacts of infected people in quarantine, there is still always the possibility that the virus could spread, Carroll said.
“The potential for local transmission within the region to neighboring countries is now of great concern,” Thomson said. Rwanda shares borders with Uganda, Tanzania, Burundi, and the Democratic Republic of Congo. And if people travel to these areas, the virus could spread further into Africa or even cause occasional cases in other parts of the world, she says.
In early October, the platform at Hamburg train station was blocked after two passengers suspected of having Marburg disease who had recently visited Rwanda were on board a train from Frankfurt. It was later confirmed that they were not infected with the virus.
Countries need to warn travelers from Rwanda about the risks and signs of Marburg disease, Carroll said. If someone develops symptoms then, he says, they can be quickly tested and isolated before an outbreak begins elsewhere.
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