One sample from a remote area in northern Tanzania has tested positive for Marburg disease, caused by a highly contagious virus that can be fatal in up to 88 percent of cases without treatment, the Tanzanian president said on Monday.

President Samia Suluhu Hassan spoke in the capital, Dodoma, alongside WHO Director-General Tedros Adhanom Ghebreyesus.

The World Health Organization was the first to report on January 14 an outbreak of suspected Marburg disease that killed eight people in the Kagera region of Tanzania. Tanzanian health officials disputed the report hours later, saying tests on the samples showed negative results.

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Hassan said Monday that additional tests confirmed Marburg’s case. She added that 25 other samples were negative.

Like Ebola, Marburg virus originates in fruit bats and spreads between people through close contact with infected bodily fluids or with surfaces, such as contaminated bedsheets.

Symptoms include fever, muscle pain, diarrhea, vomiting, and in some cases death due to severe blood loss. There is no approved vaccine or treatment for Marburg.

This is the second outbreak of Marburg virus in Kagera since 2023. It comes exactly a month after Rwanda, which shares a border with Kagera, announced the end of the outbreak.

Rwandan officials reported a total of 15 deaths and 66 infections in the outbreak that was first announced on September 27, and most of the health care workers affected were those who came into contact with the first patients.