Bubonic plague, also known as the Black Death, has claimed the lives of 32 people on the African island of Madagascar.
Madagascar has an average of 500 cases of Bubonic Plague annually and last year, 60 people died from the Black Death, making Madagascar the world's most dangerous place for contracting the disease.
"Rat control is essential for preventing the plague, because rodents spread the bacillus to fleas that can then infect humans," Christoph Vogt, head of the International Committee of the Red Cross (ICRC), told the Guardian.
Poor hygiene and living standards, the result of a long political crisis since a coup in 2009, are believed to be behind the spread of the disease.
Government officials, the ICRC and the Pasteur Institute have started a campaign to eliminate rats from prisons in the Indian Ocean state.
The Antanimora prison in the capital city of Antananarivo, which has around 3,000 prisoners is infested with rats; they spread the disease by infecting fleas through clothes, bed-sheets and food.
"The chronic overcrowding and the unhygienic conditions in prisons can bring on new cases of the disease. That's dangerous not only for the inmates but also for the population in general," said Vogt.
"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."
Around 84 suspected cases of Bubonic plague - 60 of them suspected of being pneumonic or pulmonary plague, a more virulent strain of the disease - have been reported in five of the island's 112 districts in the past month.
Pneumonic plague is caused by the same bacteria that occur in Bubonic plague and can be inhaled and transmitted between humans without involvement of animals or fleas. If untreated, it has a very high fatality rate and can kill within 24 hours.
The Pasteur Institute of Health experts believe they can contain the outbreak but spokesman Evaristo Oliviera said: "If the plague gets into prisons, there could be a sort of atomic explosion of plague within the town.
"The prison walls will never prevent the plague from getting out and invading the rest of the town."
An outbreak of Bubonic plague in Europe in the 14th century wiped out one third of the human population.