07-04-2025
Tanzania's Marburg Outbreak Ended Swiftly. Here's What We Can Learn From It
Two health workers, wearing protection outfits, leave the isolated area where people infected by the ... More deadly Marburg virus are treated at the Americo Boa Vida hospital 03 April 2005, in Luanda. The death toll from the Marburg virus epidemic rose to 235 in Angola 17 April with some 500 people under surveillance after coming in contact with the Ebola-like virus, the health ministry and the World Health Organisation said. AFP PHOTO/FLORENCE PANOUSSIAN (Photo by Florence PANOUSSIAN / AFP) (Photo by FLORENCE PANOUSSIAN/AFP via Getty Images)
The Tanzanian government declared an outbreak of Marburg virus on January 20 after one adult female became ill on December 9 and died on December 16, and a second victim was identified in January (and died Jan. 28). Another eight probable cases died before confirmation of the outbreak. With a 100% fatality rate, officials acted fast. By March 13, the government declared the end of the outbreak.
I wanted to learn more about the course of this outbreak and what lessons it can offer public health officials worldwide, so I spoke with Dr. Abdi Mahamud, a medical epidemiologist who leads a department within the World Health Organization's emergency program. He was a key leader in the Marburg outbreak response in charge of providing technical and operational support in-country. 'So, when we have an incident like this, we form the incident management system,' Mahamud said.
Marburg is a lesser-known cause of viral hemorrhagic fever than its 'cousin' Ebola, but like Ebola, it can cause outbreaks with high death rates. Marburg was discovered in 1967 after African green monkeys, imported for medical research from Uganda to Marburg, Germany, and Belgrade, Yugoslavia, touched off the first outbreak, leaving 31 infected and seven dead. Since then, there have been 18 additional outbreaks, ranging in size from one case to as many as 252 cases in the largest and deadliest outbreak (90% fatality rate), which occurred in Angola in 2004-5. Although, there have been fewer and smaller outbreaks of Marburg than those caused by Ebola species, Marburg has been on the move recently, surfacing in multiple African countries in the past five years, including: Guinea (2021), Ghana (2022), Equatorial Guinea (2023), Tanzania (2023) and Rwanda (2024).
Large fruit bats are believed to be the reservoir for Marburg. Humans initially become infected, likely after contact with bats or other infected animals, such as monkeys. Once a human is infected, the virus spreads between humans through blood or body fluids.
The disease moves quickly, with patients experiencing high fever, body aches, weakness, headache, a sore throat and a red, spotty rash in some. Illness progresses over the next few days, with vomiting and diarrhea followed by a worsening clinical course at the end of the first week or early second week. Patients' blood pressure falls, and they can go into shock or become disoriented. Some people's skin oozes in areas where they've had blood drawn or intravenous line were placed.
The WHO has a network of 'public health intelligence' partners around the globe that feed it information on potential emergencies. Staff comb through the approximately 7,000 potential signals that come in regularly and 200 emails that arrive daily. A typical email might state, 'There's something going on here – at least be aware.'
Personnel then work to verify reports through country leaders and other partners. A U.S. government-supported non-governmental organization sent the initial report on a possible outbreak of a viral hemorrhagic fever occurring in the Kagera region of Tanzania.
There were some initial mixed messages between the WHO and the Tanzanian Ministry of Health, but the response aligned when WHO Director-General Dr. Tedros Adhanom Ghebreyesus visited Dar es Salaam on Jan. 20 and pledged support alongside Tanzanian President Samia Suluhu Hassan. This alignment of response and resources was critical, because the northwest Kagera region is close to border regions for multiple countries, including Burundi, Rwanda, Uganda and Kenya. WHO leaders wanted to prevent the type of cross-border spread that occurred during the largest Ebola outbreak ever, from 2014-16 in West Africa, which led to international spread, with 28,610 cases and 11,308 deaths.
World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus (L) speaks during a ... More joint news conference with Tanzanian President Samia Suluhu Hassan in the Tanzanian capital of Dodoma, Jan. 20, 2025. Tanzanian President Samia Suluhu Hassan on Monday confirmed the country's second outbreak of Marburg virus disease (MVD) in two years. Speaking at a joint news conference with World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus, Hassan said that laboratory tests conducted at the Kabaile mobile laboratory in the northwestern Kagera region and later confirmed in Dar es Salaam identified one person in Biharamulo District as infected with MVD. (Tanzania State House/Handout via Xinhua)
Dr. Mahamud was deployed as part of a 26-member team from WHO's headquarters, Africa regional and Tanzania offices to Kagera for nine days, and WHO assumed a supporting role that was 'Fully integrated with the MOH response,' he said.
The WHO brings in specific expertise to assist across multiple response pillars, such as research and development, lab diagnostics, infection prevention and control, clinical management and training. Another major WHO role is coordinating multiple partners, including the Médecins sans Frontières (Doctors Without Borders), UNICEF, International Federation of the Red Cross and Red Crescent Societies, Africa Centers for Disease Control, U.S. CDC as well as community-based partners. WHO also helped build a surveillance system, a system for community engagement, contract tracing and training on safe, dignified burials.
I asked Dr. Mahamud why there were only 10 cases, given how contagious Marburg can be to close family and healthcare contacts. He attributed this small number to significant outreach provided to 42 health facilities at risk and community workers who visited almost 73,000 households to search for cases and share prevention information. Also, officials quarantined anyone with potential exposure to the virus and gave them basic food and shelter in a hotel. They also took care of families, which was critical to gain the buy-in and trust of the involved communities.
The other aspect that may have helped reduce spread was the outbreak's location. Unlike a recent outbreak in the capital city of Kigali, Rwanda, where many healthcare workers became infected, Kagera is a rural region with a lower population density, likely resulting in fewer opportunities for the virus to spread.
There are no approved treatments or vaccines for Marburg, although there is ongoing research to develop them. During the outbreak response in Rwanda, authorities used an experimental vaccine for personnel at risk of infection, but as a product still under study, it had to be given with full informed consent and under a research protocol. This takes time to assemble, translate into local languages and approve through an ethical review board. The WHO and the Ministry of Health were putting the protocol together and the clinical trial was ready to be launched, but the outbreak ended too quickly to use the products. They'll be ready if another outbreak occurs in Tanzania in the future.
I asked Dr. Mahamud what lessons we can take away from this outbreak response. 'Viral hemorrhagic fevers will happen,' he noted, adding that, 'the frequency and intensity will increase.' This is because three factors he called the 'three Es' align to create a situation conducive for outbreaks:
According to Dr. Mahamud, in order to be prepared, we need to invest in better disease surveillance and other preparedness efforts to support the countries in need. We also must view a disease like Marburg through the lens of global health security and recognize the importance of partnerships to execute rapid and efficient responses to prevent cross-border and international spread.
During our discussion, I couldn't help wondering how the response to a similar outbreak might play out in the future given the U.S. has withdrawn from the WHO and reduced the size of the U.S. CDC staff by around 18%. In addition, given that the initial outbreak report was sent by a U.S. government-funded NGO, how timely will future reports be after the cutoff of USAID support, and what will the impact be for vulnerable populations around the globe, not to mention global health security? The next outbreak is no doubt just around the corner, which will give us a chance to test the response effectiveness.
