Twenty people have died following a deadly outbreak of the bubonic plague, medical experts on the island of Madagascar have confirmed.
Public Health officials had warned of the risk of an outbreak in October.
In 2012, 256 cases of the disease were recorded and 60 people died, making Madagascar the most severely affected country in the world. The disease is transmitted to humans usually via rat fleas and prisoners typically face the highest risk because of their living conditions.
The International Committee of the Red Cross (ICRC) and the Pasteur Institute had said Madagascar's dirty, overcrowded prisons could be an ideal breeding ground for the disease.
They have been working with local health groups on schemes to improve prison hygiene and reduce rats in a bid to fight the plague at Antanimora Prison in Antananarivo, where 3,000 inmates are held.
"The chronic overcrowding and the unhygienic conditions in prisons can bring on new cases of the disease," Christoph Vogt, head of the ICRC delegation in Madagascar had said in October. "That's dangerous not only for the inmates but also for the population in general."
He added: "Rat control is essential for preventing the plague, because rodents spread the bacillus to fleas that can then infect humans. So the relatives of a detainee can pick up the disease on a visit to the prison. And a released detainee returning to his community without having been treated can also spread the disease."
According to the ICRC, an average of 500 cases have been recorded on the island every year since 2009. Africa is now believed to account for more than nine out of ten bubonic plague cases worldwide.