At least five people have died in north-west Tanzania from an unidentified illness, officials say.
Seven cases have so far been reported in Kagera region and the authorities have dispatched a team of doctors to diagnose the disease.
Health authorities in the East African country have described the illness as strange.
Its symptoms include fever, headaches, fatigue and nosebleeds, according to the government’s chief medical officer Tumaini Nagu.
“The government formed a regional team of professionals under the Rapid Response Team who are investigating this unknown disease,” Prof Nagu said on Thursday evening.
She asked residents in the area to remain calm and avoid contact with infected people.
In July last year, more than 20 cases with similar symptoms were reported in the southern Lindi region. Three people died from the outbreak.
Investigations later identified the disease as leptospirosis, also known as Weil’s disease.