WHO warns of high-risk Marburg outbreak in Tanzania

The World Health Organisation has confirmed an outbreak of suspected Marburg Virus Disease in Tanzania.

The WHO who disclosed this on its website on Tuesday, noted that the source of the outbreak is currently unknown.

It stated that the risk of the suspected MVD outbreak is assessed as high at the national level due to several concerning factors, and the regional risk is considered high due to the Kagera region’s strategic location as a transit hub.

It mentioned that there is no confirmed international spread at the moment, but there are concerns about potential risks.

It said, “On 13 January 2025, WHO informed its Member States and International Health Regulations State Parties of an outbreak of suspected MVD in the Kagera region of the United Republic of Tanzania using our secure web-based platform—the Event Information Site. Under the International Health Regulations, the EIS is used to issue rapid alerts to Member States of acute and rapidly developing public health risks and events with possible international implications.

“On 10 January 2025, WHO received reliable reports from in-country sources regarding suspected cases of MVD in the Kagera region of the United Republic of Tanzania. Six people were reported to have been affected, five of whom had died. The cases presented with similar symptoms of headache, high fever, back pain, diarrhoea, haematemesis (vomiting with blood), malaise (body weakness) and, at a later stage of disease, external haemorrhage (bleeding from orifices).

“As of 11 January 2025, nine suspected cases were reported including eight deaths (case fatality ratio of 89 per cent) across two districts – Biharamulo and Muleba. Samples from two patients have been collected and tested by the National Public Health Laboratory. Results are pending official confirmation. Contacts, including healthcare workers, are reported to have been identified and under follow-up in both districts.”

The Bukoba district in the Kagera region experienced its first MVD outbreak in March 2023, and zoonotic reservoirs, such as fruit bats, remain endemic to the area. The outbreak in March 2023 lasted for nearly two months with nine cases including six deaths.

Meanwhile, the global health body noted that the national rapid response teams have been deployed to support outbreak investigation and response; surveillance activities have been intensified with contact tracing ongoing; laboratory samples from recent cases have been sent for confirmation at the National Public Health Laboratory.

It added that the mobile laboratory is located in the Kagera region and treatment units have reportedly been established.

It highlighted that “The risk of this suspected MVD outbreak is assessed as high at the national level due to several concerning factors. The suspected outbreak thus far involves at least nine suspected cases, including eight deaths, resulting in a high CFR of 89 per cent. Healthcare workers are included among the suspected cases affected, highlighting the risk of nosocomial transmission. The source of the outbreak is currently unknown. The reporting of suspected MVD cases from two districts suggests geographic spread. The delayed detection and isolation of cases, coupled with ongoing contact tracing, indicates lack of a full information of the current outbreak. More cases are expected to be identified.

“The regional risk is considered high due to the Kagera region’s strategic location as a transit hub, with significant cross-border movement of the population to Rwanda, Uganda, Burundi and the Democratic Republic of the Congo. Reportedly, some of the suspected cases are in districts near international borders, highlighting the potential for spread into neighbouring countries. MVD is not easily transmissible (i.e. in most instances, it requires contact with the body fluids of a sick patient presenting with symptoms or with surfaces contaminated with these fluids). However, it cannot be excluded that a person exposed to the virus may be travelling.

“The global risk is currently assessed as low. There is no confirmed international spread at this stage, although there are concerns about potential risks. Kagera region, while not close to Tanzania’s capital or major international airports, is well-connected through transportation networks, and has an airport that connects to Dar es Salaam for onward travel outside Tanzania by air. This highlights the need for enhanced surveillance and case management capacities at relevant points of entry and borders, and close coordination with neighbouring countries to strengthen readiness capacities.”

WHO advised individuals to take protective measures to reduce human exposure to the virus.

It also said raising public awareness and engaging with communities are important for successfully controlling MVD outbreaks.”Based on the current risk assessment, WHO advises against any travel and trade restrictions with the United Republic of Tanzania,” it added.