Following a World Health Organization (WHO) alert 2 days ago about a suspected Marburg virus outbreak in Tanzania, the country's health ministry said yesterday that tests on collected samples were negative for the disease. The WHO had based its alert on reliable in-country sources.

At a WHO briefing today, however, Director-General Tedros Adhanom Ghebreyesus, PhD, urged Tanzania's government send its samples for testing to international reference labs and to collect additional samples in accordance with normal procedures. He also said the WHO is supporting Tanzania's response and has offered to provide any additional support that is needed.
Index patient died in December; 300 contacts identified
Top officials from the Africa Centres for Disease Control and Prevention (Africa CDC) hosted their regular weekly telebriefing from Tanzania today and added more details about the outbreak, including that the suspected index case-patient is a 27-year-old pregnant woman who had an illness that progressed to hemorrhagic symptoms and died on December 16, 2024.
Jean Kaseya, MD, MPH, Africa CDC’s director-general, acknowledged official communication from Tanzania's government that no Marburg virus has been confirmed in lab tests. He said the government has Marburg virus test kits that were distributed as part of the regional response to Rwanda's Marburg virus outbreak last year. "We are supporting Tanzania. For now, this is the comment we can make."
A health worker involved in the woman's care became ill and died on December 27. So far, nine illnesses have been reported, and eight patients have died from their infections. Samples were collected from five patients.
So far, investigators have identified 300 contacts, including 56 healthcare workers. Africa CDC said 16 of the contacts had direct contact with sick patients.
If confirmed, the outbreak would be Tanzania's second Marburg event. In 2023, an outbreak in the same region resulted in nine illnesses, six of them fatal.