The World Health Organization (WHO) on January 13th, 2025, through their secure Event Information Site (EIS), confirmed an outbreak of Marburg virus disease in Tanzania’s Kagera region.
In an alert issued to countries, WHO confirmed that nine cases have been reported, including eight fatalities across two districts—Biharamulo and Muleba in the Kagera region.
“We are aware of nine cases so far, including the eight who have died. We would expect further cases in the coming days as disease surveillance improves, WHO’s statement reads.
WHO has offered its full assistance to the Tanzanian government to support affected communities in the region.
“We recommend neighboring countries be on alert and prepared to manage potential cases. However, we do not recommend travel or trade restrictions with Tanzania at this time,” WHO advised.
The Tanzanian government and WHO are working tirelessly to control the outbreak, including contact tracing and heightened surveillance in the Kagera region.
Globally, more than 700 cases have been recorded over the years, including a small outbreak in Uganda in October 2017 that claimed three lives in Kween district in the Eastern region.
The Kagera region borders the southwestern districts of Uganda: Kyotera, Isingiro, and Ntungamo, which puts them highly at risk due to cross-border activities.
Key facts
- Marburg virus disease (MVD), formerly known as Marburg hemorrhagic fever, is a severe, often fatal illness in humans.
- The average MVD case fatality rate is around 50%. Case fatality rates have varied from 24% to 88% in past outbreaks.
- Early supportive care with rehydration and symptomatic treatment improves survival.
- There are currently no approved vaccines or antiviral treatments for MVD, but a range of vaccines and drug therapies are under development.
- Rousettus aegyptiacus, a fruit bat of the Pteropodidae family, is considered the natural host of Marburg virus. The Marburg virus is transmitted to people from fruit bats and spreads among humans through human-to-human transmission.
- Community engagement is key to successfully controlling outbreaks.
Transmission
In the human population, Marburg virus can spread through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs, or other bodily fluids of infected people, and with surfaces and materials (e.g., bedding, clothing) contaminated with these fluids.
Healthcare workers have frequently been infected while treating patients with suspected or confirmed MVD. This has occurred through close contact with patients when infection control precautions are not strictly practiced. Transmission via contaminated injection equipment or through needle-stick injuries is associated with more severe disease, rapid deterioration, and possibly a higher fatality rate.
Burial ceremonies that involve direct contact with the body of the deceased can also contribute to the transmission of Marburg virus.
People cannot transmit the disease before they have symptoms and remain infectious as long as their blood contains the virus.
Symptoms of Marburg virus disease
The incubation period (interval from infection to onset of symptoms) varies from 2 to 21 days.
MVD begins abruptly, with high fever, severe headache, and severe malaise. Muscle aches and pains are a common feature. Severe watery diarrhea, abdominal pain and cramping, nausea, and vomiting can begin on the third day. Non-itchy rashes have been reported in patients between 2 and 7 days after onset of symptoms.
From day 5 of the disease, patients may develop hemorrhagic manifestations, including fresh blood in vomitus and feces and bleeding from the nose, gums, and vagina. Bleeding at venepuncture sites (where intravenous access is obtained to give fluids or obtain blood samples) can also be observed. Involvement of the central nervous system can result in confusion, irritability, and aggression. Orchitis (inflammation of one or both testicles) has been reported occasionally in the late phase of disease.
In fatal cases, death occurs most often between 8 and 9 days after symptom onset, usually preceded by severe blood loss and shock.
Treatment and vaccines
Early intensive supportive care, including rehydration and treatment of specific symptoms, can improve survival.
Currently there are no vaccines or antiviral treatments approved for MVD.
There are candidate monoclonal antibodies (mAbs) and antivirals, along with candidate vaccines that can be evaluated in clinical trials.
Prevention and control
Community engagement is key to successfully controlling any outbreaks. Outbreak control relies on using a range of interventions, such as case management, surveillance and contact tracing, good laboratory service, infection prevention and control in health facilities, safe and dignified burials, and social mobilization.
Raising awareness of risk factors for MVD and protective measures that individuals can take is an effective way to reduce human transmission.
Risk reduction messaging should focus on several factors:
- Reducing the risk of bat-to-human transmission arising from prolonged exposure to mines or caves inhabited by fruit bat colonies. People with visiting or working in mines or caves inhabited by fruit bat colonies should wear gloves and other appropriate protective clothing (including masks). During outbreaks, all animal products (blood and meat) should be thoroughly cooked before consumption.
- Reducing the risk of human-to-human transmission in the community arising from direct or close contact with infected patients, particularly with their body fluids. Close physical contact with MVD patients should be avoided. Patients suspected or confirmed for MVD should be isolated in a designated treatment center for early care and to avoid transmission at home.
- Communities affected by MVD should make efforts to ensure that the population is well informed, both about the nature of the disease itself and about necessary outbreak containment measures.
- Outbreak containment measures include safe and dignified burial of the deceased, identifying people who may have been in contact with someone infected with MVD and monitoring their health for 21 days, separating the healthy from the sick to prevent further spread, and providing care to confirmed patients, and maintaining good hygiene and a clean environment need to be observed.
