The victim -- a mine worker -- re-entered a closed gold mine near the border with the Democratic Republic of Congo, where the disease erupted in August, the ministry said in a statement.
"The case has been identified, isolated and confined in one of the health facilities in the country," it said.
The disease killed one person during the outbreak.
Scientists in August discovered its source to be the African fruit bat found all across sub-Saharan Africa.
Marbug fever spreads through contact with blood, excrement, vomit, saliva, sweat and tears.
No vaccine or drug therapy has proven effective in warding off or curing the disease, which causes horrendous symptoms including internal bleeding, high fevers, coma and renal failure.
Death from shock usually occurs a week after clinical onset of symptoms.
The disease takes its name from the German town of Marburg, where it was first detected, in 1967, among lab workers who were infected by monkeys from Uganda.