RWAMPARA, Congo — Dozens of people working at an Ebola virus treatment center in northeast Congo went on strike Monday over unpaid salaries and bonuses, posing a new challenge for the fastest-growing Ebola outbreak ever recorded on the continent.

Congo since May has been battling the outbreak of a type of Ebola with no approved treatment or vaccine. Last week, the Congolese health minister, Roger Kamba, said the virus had spread to two more provinces.

The striking staff at Rwampara General Hospital in Ituri province, the epicenter of the outbreak, includes epidemiologists, case investigators, drivers and gravediggers who say they have not been paid by Congolese authorities. The protesting staff shut the hospital and blocked the road leading to it, even burning a tire outside.

“We don’t know how it is possible to not have been paid for two months,” Bahati Claude, a health worker at the hospital told The Associated Press. “We don’t want to give up the job.”

The treatment center is different from the one in Ituri where a study of two badly needed treatments began earlier this month.

Congolese authorities declared the Ebola outbreak on May 15, after the disease had been transmitting for weeks without official detection, according to the World Health Organization. The outbreak is caused by the rare Bundibugyo virus, and the delay in confirming the outbreak came in part because tests were done for a more common type of Ebola.

During a visit to Ituri last week, Congo’s health minister said the government is verifying a list of those working to control the outbreak, as some unrelated names have been added to the payroll.

“We must ensure that these payments reach the right people,” Kamba said. “We have faced a few challenges, notably changes to the lists, which have led to complaints from people saying they are not being paid even though they are working. We have the means to sort this out.”

There are 1,926 confirmed cases in the country, including 702 deaths, according to Congolese authorities.

Meanwhile, WHO Director-General Tedros Adhanom Ghebreyesus posted Monday on X that a second U.S. citizen, a humanitarian worker in eastern Congo who had contracted Ebola, was transferred to Germany. The first American to test positive for the virus was a doctor working in Congo during the early weeks of the outbreak.