The outbreak, which has been reported in two districts, Biharamulo and Muleba, has raised alarm due to its high case fatality ratio (CFR) of 89% and its potential regional implications.
In a statement dated January 14, 2025, WHO said the agency received reliable reports from in-country sources regarding suspected MVD cases on January 10, 2025.
"Six people were reported to have been affected, five of whom had died," the statement reads in part.
According to WHO, by January 11, the number of suspected cases had risen to nine, with eight deaths.
Symptoms observed included high fever, headache, back pain, diarrhoea, vomiting with blood (haematemesis), body weakness (malaise), and external haemorrhage in later stages.
WHO formally alerted its Member States and International Health Regulations (IHR) State Parties on 13 January through its Event Information Site (EIS), a secure web-based platform for issuing rapid alerts of public health risks with potential international implications.
Tanzania's national rapid response teams have been deployed to support outbreak investigations, intensify surveillance activities, and trace contacts of suspected cases.
Laboratory samples from two patients have been sent to the National Public Health Laboratory for confirmation, while a mobile laboratory has been established in the affected region to expedite testing. Treatment units have also been set up to manage suspected cases.
The outbreak follows a previous MVD incident in the same region in March 2023, during which nine cases were reported, resulting in six deaths. The Kagera region is known to harbour zoonotic reservoirs, such as fruit bats, which are natural hosts of the Marburg virus.
WHO assesses the national risk level as high due to the outbreak's high CFR, its geographic spread across two districts, and the involvement of healthcare workers among the suspected cases. The delayed detection of cases and incomplete information on the outbreak heighten concerns.
According to the global health agency, the region's strategic location as a transit hubâ€"with significant cross-border movement involving neighbouring countries such as Rwanda, Uganda, Burundi, and the Democratic Republic of the Congoâ€"further raises the potential for regional spread.
Globally, the risk is considered low at this stage, as there is no confirmed international spread. However, the Kagera region's connectivity through transportation networks and its airport linking to Tanzania's capital and beyond underscores the need for enhanced surveillance and coordination.
To control the outbreak and reduce transmission, individuals have been urged to avoid direct contact with the blood and bodily fluids of infected patients.
Those suspected or confirmed to have Marburg Virus Disease should seek care at designated treatment centers to prevent household transmission.
Communities are also strongly advised to adhere to safe burial protocols for deceased individuals to minimize the risk of further spread.
WHO has also emphasized the necessity of cross-border collaboration with neighbouring countries to harmonize reporting systems, share critical data, and strengthen readiness capacities.
Enhanced surveillance at points of entry and in border regions is vital to preventing the international spread of the virus.
The suspected outbreak in Tanzania comes just weeks after Rwanda declared the end of its Marburg virus outbreak on December 20, 2024.
The Rwandan outbreak, which began in mid-September, affected 66 individuals, resulting in 15 fatalities and 51 recoveries.
Wycliffe Nyamasege
