As health officials in Congo celebrated the discharge of the last Ebola patient from its treatment center in Beni on Tuesday, the World Health Organization (WHO) cautioned that the outbreak was not yet in the past.

"The celebration in Beni is great news and the result of tremendous hard work by Congolese health workers," the WHO noted in a statement, while warning that the risk of additional cases emerging remains high.

Videos of health workers singing and dancing as they ushered out their last patient were shared on social media by WHO's African office.

The U.N. agency declared a "public health emergency of international concern" in July to rally international support for the health crisis in Congo, and to highlight the risk that the virus could spread to neighboring countries.

More than 3,400 people have been infected with hemorrhagic fever in Congo's eastern border region. More than 2,200 have died since the disease started spreading in mid-2018. The fragile security situation in the outbreak region has made the work of medical teams on the ground extremely difficult and dangerous.

Although transmission has dropped, the WHO stated its teams would remain in "full response mode." The outbreak will only be declared finished after no new infections appear for 42 days.