The World Health Organization has announced a suspected outbreak of Marburg Virus Disease in Tanzania, specifically in the Kagera region.
The WHO disclosed this update on its website on Tuesday, revealing that the source of the outbreak remains unidentified.
The organization assessed the risk at the national level as high, citing several troubling factors, while also classifying the regional risk as high due to Kagera’s strategic role as a transit hub.
Despite these concerns, no confirmed international spread has been reported at this time.
According to WHO, “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.”
Reports indicated the WHO received initial information on 10 January 2025 regarding possible MVD cases in the Kagera region. Six individuals were affected, with five fatalities.
Symptoms included headache, high fever, back pain, diarrhea, vomiting blood (haematemesis), body weakness (malaise), and external bleeding during later stages.
As of 11 January 2025, the outbreak had affected nine individuals across the Biharamulo and Muleba districts, claiming eight lives—an alarming case fatality rate (of 89%. Test results for samples collected from two patients are still pending confirmation.
This outbreak follows a prior MVD occurrence in March 2023, also in Bukoba district within the Kagera region. That outbreak, linked to zoonotic reservoirs like fruit bats, lasted nearly two months, resulting in nine cases and six deaths.
WHO highlighted the steps taken by Tanzanian authorities, stating that rapid response teams have been deployed to aid in outbreak investigation and response.
Contact tracing efforts are ongoing, and laboratory samples have been sent to the National Public Health Laboratory for analysis. Mobile laboratories and treatment facilities have also been established in the region.
WHO underscored the seriousness of the situation, explaining, “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 WHO also expressed concern about the region’s connectivity and potential for cross-border transmission, stating, “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.”
While the global risk remains low, WHO emphasized the need for heightened surveillance and preparedness at borders and key transit points, as well as collaboration with neighboring countries to bolster readiness.
In its advisory, the global health body recommended protective measures to reduce human exposure to the virus. It also stressed the importance of raising public awareness and engaging communities to effectively manage MVD outbreaks.
WHO clarified, “Based on the current risk assessment, WHO advises against any travel and trade restrictions with the United Republic of Tanzania.”
