The Health Ministry on Wednesday said that four people have died from the plague since Nov. 15 in Southern Befotaka District, in Madagascar.
The Indian Ocean Island State is the country that was most affected by the plague, which killed millions of people in the world in earlier centuries.
The four victims died of bubonic plague, which affects the lymph nodes.
The plague may have been brought to the Befotaka area by rats fleeing forest fires, Health Ministry official Willy Randriamarotia said.
A team of experts from the ministry, the World Health Organisation and the Research Centre Institute Pasteur had been sent to the area.
This year, 56 cases had been recorded since the end of August, four of whom have now died.
The plague could be cured with antibiotics, but if it affected the lungs, it could be fatal within 24 hours.
The high incidence of the plague in Madagascar had been attributed to a combination of factors, including poor hygiene and health care.