Marburg virus disease - United Republic of Tanzania

India

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New Delhi, March 25, 2023

As response measures, Rapid Response Teams have been deployed to investigate and implement interventions in the affected areas, including contact tracing and risk communication activities. WHO assesses the risk of spread as very high at the national level, high at the subregional level, and moderate at the regional level due to cross-border movements between Kagera region and bordering countries including Uganda in the north, Rwanda and Burundi in the west. The risk at the global level is assessed to be low.

On 16 March 2023, the MoH of the United Republic of Tanzania announced that seven cases and five deaths from an unknown disease had been reported in two villages in Bukoba district, Kagera region, northern Tanzania. The cases were later confirmed as Marburg virus infection by reverse transcriptase-polymerase chain reaction (RT-PCR) at the National Public Health Laboratory, Tanzania. On 21 March 2023, the MoH officially declared the first MVD outbreak in the country.

As of 22 March, eight cases, including five deaths (case fatality ratio [CFR]: 62.5%) have been reported from Kagera region. The remaining three patients are currently undergoing treatment. As of 22 March, no cases have been reported from outside the Bukoba district of Kagera Region.

Marburg virus disease is an epidemic-prone disease associated with high case-fatality rates (CFR 24-90%). It is caused by the same family of viruses (Filoviridae) as Ebola virus disease and is clinically similar. The current CFR for this outbreak is relatively high, at 62.5%.

Marburg virus infection often results from prolonged exposure to mines or caves inhabited by Rousettus bat colonies. Once an individual is infected with the virus, it can spread through human-to-human transmission via direct contact with the blood, secretions or other body fluids of infected or deceased people. Healthcare workers have previously been infected while treating patients with suspected or confirmed MVD. Burial ceremonies that involve direct contact with the body of the deceased can also contribute to the transmission of Marburg.

The incubation period varies from two to 21 days. Illness caused by Marburg virus begins abruptly, with high fever, severe headache, and severe malaise. Severe watery diarrhoea, abdominal pain and cramping, nausea, and vomiting can begin around the third day. Severe haemorrhagic manifestations may appear between five and seven days from symptom onset, and fatal cases usually have some form of bleeding, often from multiple areas. In fatal cases, death occurs most often between eight and nine days after symptom onset, usually preceded by severe blood loss and shock.

Clinical diagnosis of MVD is difficult in the early phase as symptoms are similar to other febrile illnesses. The differential diagnosis for MVD may include other filovirus diseases, Lassa fever, malaria, typhoid fever, dengue, rickettsial infections, leptospirosis and plague.

Laboratory confirmation is primarily made by RT-PCR. Other tests can be used such as antibody-capture enzyme-linked immunosorbent assay (ELISA), antigen-capture detection tests, serum neutralization tests, electron microscopy, and virus isolation by cell culture.

Although there are no vaccines or antiviral treatments for MVD, supportive care – such as rehydration with oral or intravenous fluids – and treatment of specific symptoms improve survival. A range of potential treatments are being evaluated, including blood products, immune therapies, and drug therapies.

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