KINSHASA, Congo (AP) — Congo is struggling to contain its biggest mpox outbreak, and scientists say a new form of the disease detected in a mining town might more easily spread among people.

Since January, Congo has reported more than 4,500 suspected mpox cases and nearly 300 deaths, numbers that have roughly tripled from the same period last year, according to the World Health Organization. Congo recently declared the outbreak across the country a health emergency.

An analysis of patients hospitalized between October and January in Kamituga, eastern Congo, suggests recent genetic mutations in mpox are the result of its continued transmission in humans; it’s happening in a town where people have little contact with the wild animals thought to naturally carry the disease.

“We’re in a new phase of mpox,” said Dr. Placide Mbala-Kingebeni, the lead researcher of the study, who said it will soon be submitted to a journal for publication. Mbala-Kingebeni heads a lab at Congo’s National Institute of Biomedical Research, which studies the genetics of diseases.