Experts have stated that Madagascar is facing a bubonic plague epidemic if they do not find a way to stem the growth of the illness.

Both the Red Cross and the Pasteur Institute say that the island nation’s jails have been overrun by rats and pose an extremely serious risk for spreading the disease.

“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,” said the institute’s Christophe Rogier told the BBC.

Last year, the country recorded the world’s highest number of confirmed cases of plague and the highest number of deaths. The disease is spread both by rats and the fleas that infest the rats.

October is start of the plague season in Madagascar because the hot, humid weather increases the amount of fleas.