Three people have died in Tanzania’s Lindi region in recent days after contracting an unidentified illness characterized by symptoms including “nosebleeds, fever, headaches and fatigue,” Africanews reported on Thursday.

Tanzania’s government sent a team of medical professionals to Lindi this week to investigate the “nosebleed disease,” which has infected at least 13 people since July 5 according to the Tanzania Daily News.

“The government has formed a team of professionals who are still investigating the unknown disease,” the Tanzanian government’s chief medical officer, Aifello Sichalwe, told reporters on Wednesday.

He said the medical team had already ruled out “Ebola, Marburg virus and Covid-19 [Chinese coronavirus]” as the identity of the mystery illness, as the patients tested negative for all three of these diseases.

“One of them has recovered while the others are in isolation,” Sichalwe noted of the patients.

Tanzania President Samia Suluhu Hassan told attendants of a religious gathering on July 12 that “the ‘strange’ disease detected in Lindi could have been caused by ‘increasing interactions’ between humans and animals due to environmental degradation,” as quoted by Africanews.

The Tanzania Daily News quoted President Hassan as saying that “apart from nosebleed, the disease causes fatigues and subsequently collapsing of the people infected.”

Tanzania President Samia Suluhu Hassan: “The ‘strange’ disease detected in Lindi could have been caused by ‘increasing interactions’ between humans and animals due to environmental degradation.” (BRENDAN SMIALOWSKI/AFP via Getty Images)

She made the remarks at the “20th Plenary Assembly of Association of Member Episcopal Conference in Eastern Africa (AMECEA)” in Dar es Salaam, according to the newspaper.

Speaking to reporters from Dodoma, Tanzania’s national capital, on July 13, Sichwale said health officials first detected the mystery illness in Lindi’s Ruangwa district on July 5.

“In three days consecutive days (July 5 to 7), the [Mbekenyera Health] center received two patients with fever symptoms, nose bleeds, severe headache and fatigue [sic],” he said.

The Lindi clinic admitted 13 patients with the disease as of July 12, three of whom subsequently died.

“Ghana last week detected two suspected cases of Marburg virus, a haemorrhagic fever almost as deadly as Ebola,” Africanews recalled on July 14.

Tanzania is located in East Africa along the continent’s Indian Ocean coast while Ghana lies in West Africa along the continent’s Atlantic Ocean coast.

Both Marburg and Ebola are diseases belonging to the Viral hemorrhagic fever (VHF) group that demonstrate high rates of fatality.

“Ebola virus disease (EVD) is a deadly disease with occasional outbreaks that occur mostly on the African continent. EVD most commonly affects people and nonhuman primates (such as monkeys, gorillas, and chimpanzees),” according to the U.S. Centers for Disease Control and Prevention (CDC).

“Marburg virus disease (MVD) is a rare but severe hemorrhagic fever which affects both people and non-human primates. MVD is caused by the Marburg virus, a genetically unique zoonotic (or, animal-borne) RNA virus of the filovirus family. The six species of Ebola virus are the only other known members of the filovirus family,” the CDC writes.