And experts say the epidemic could still worsen as the death tolls hits 124 and more than 1,300 left infected.
The Medieval disease famously wiped out ONE THIRD of Europe's population in the 13th and 14th centuries in one of the most devastating pandemics in human history known as the Black Death.
Dr Ashok Chopra, a professor of microbiology and immunology at the University of Texas, told The Sun Online the crisis in Madagascar had yet to peak.
He warned it was possible for the deadly plague to move further into the region given the regular flights going in and out of the country.
"If they are travelling shorter distances and they're still in the incubation period, and they have the pneumonic (form) then they could spread it to other places.
"We don't want to have a situation where the disease spreads so fast it sort of gets out of control."
He added: "Most of the cases in the past have been of the bubonic plague but if you look at this particular outbreak, 70 percent of the cases are pneumonic plague, which is the most deadly form of the disease.
"If the treatment is not given in a very short period of time these people will end up dying."
Plague symptoms include sudden fevers, head and body aches, vomiting and nausea.
Dr Chopra added that it spreads "very rapidly", as seen by the number of cases in Madagascar doubling within a week.
Speaking from Madagascar, Christine South, head of IFRC's emergency operations, said: "With anything like this there is a possibility that somebody could be infected and get on a plane.
"We have done preparedness support to some of the neighbouring countries."
However, she added that she believed the plague outbreak may now be stabilising but medical staff would have a clearer understand of this over the next few days.
