On 16 March 2023, the Ministry of Health (MOH) of the Republic of Tanzania announced that an unknown disease had claimed the lives of five people in the Kagera region, which borders Rwanda, Uganda, and Burundi. The MOH reported that seven cases had been confirmed, with the cases occurring in Bukoba rural, Maruku, and Kanyengereko ward in Bulinda and Butayaibega villages.

On 21 March 2023, the MOH confirmed that the cases were due to the Marburg Virus Disease (MVD). The index case was reported to have a travel history from Goziba in Lake Victoria and developed symptoms upon returning to his village in Bukoba. The timeline for exposure and onset of symptoms is still unknown. Four other cases were from the same family as the index case, and two healthcare workers were also infected, with one of them succumbing to the disease.

The MOH stated that this is the first officially declared Marburg outbreak in Tanzania, although previous serological studies have found the presence of the virus in bat populations in the region. As of 22 March 2023, a total of eight cases had been reported, with five deaths (CFR 63.6%), while the other three cases are currently undergoing treatment in health facilities in the Kagera region. The cases had symptoms of fever, bleeding from various body parts, and kidney failure. Specimens from the deceased and living patients were collected and confirmed MVD by RT-PCR at the National Health Laboratory.

The MOH has reported that the outbreak is confined to Bukoba council in the Kagera region, and contact tracing activities have been initiated, with a total of 195 contacts identified and 185 of them being monitored. The MOH is also urging residents to practice good hygiene and report any suspected cases of the disease promptly. The MOH has assured the public that it is working to contain the outbreak and prevent its spread to other areas of the country.