The Ebola virus epidemic in Guinea, Sierra Leone and Liberia is “out of control,” the medical charity Doctors without Borders said Monday as the World Health Organization (WHO) works to enhance its response.

EuroNews reported that there have been over 350 deaths since the epidemic began in Guinea’s capital, Conakry, in February, according to WHO. It is the deadliest outbreak since Ebola first emerged in 1976.

“The epidemic is out of control,” said Bart Janssens, director of operations with Doctors without Borders. “With the appearance of new sites in Guinea, Sierra Leone and Liberia, there is a real risk of it spreading to other areas.”