Beni, Congo -- The Congolese health ministry confirmed an Ebola case in Goma late Sunday, marking the first time the virus has reached the city of more than 2 million people along the border with Rwanda since the epidemic began nearly a year ago. The health ministry said the man who arrived earlier Sunday in the regional capital was quickly transported to an Ebola treatment center.

Authorities said they had tracked down all the passengers on the bus the man took to Goma from Butembo, one of the towns hardest hit by the disease.

"Because of the speed with which the patient was identified and isolated, and the identification of all the other bus passengers coming from Butembo, the risk of it spreading in the rest of the city of Goma is small," the health ministry said in a statement.

Get Breaking News Delivered to Your Inbox Click here to view related media. click to expand

Nonetheless, the head of the World Health Organization said the confirmed case in crowded Goma could be a game-changer in how the central African outbreak is tackled. One month ago, when the disease spread into Uganda, the WHO convened and decided it still did not rise to the level of a global health emergency. For such a declaration, an outbreak must constitute a risk to other countries and require a coordinated response. The declaration typically triggers more funding and political attention.

On Monday, WHO chief Tedros Adhanom Ghebreyesus said he hoped the virus would not spread in Goma, but he convened a meeting of the organization's emergency committee to discuss a possible global emergency declaration.

The virus has killed more than 1,600 people in Congo and two others who returned home across the border to neighboring Uganda. Health experts have long feared that it could make its way to Goma, which is located on the Rwandan border.

Health workers prepare to bury a coffin containing a victim of the Ebola virus on May 16, 2019 in Butembo, a city at the center of the outbreak. Getty

The health ministries in Congo's neighbors have been preparing for months for the possibility of cases, and frontline health workers already have been vaccinated.

The confirmed case announced late Sunday in eastern Congo involves a pastor who became ill last Tuesday. He then left Butembo on a bus, and arrived at a health center Sunday showing symptoms of Ebola, the health ministry said.

The other killer in Congo

Violent attacks against health workers and treatment facilities have greatly compromised efforts to combat the epidemic in Butembo. Officials with Congo's Health Ministry said Monday that unidentified attackers had killed two Ebola community health workers over the weekend in North Kivu province. The workers had been receiving threats for months, the ministry said.

This outbreak, occurring close to Congo's borders of Uganda, Rwanda and South Sudan, has been like no other. Mistrust has been high in a region that had never faced Ebola before and the attacks by rebel groups have undermined aid efforts.

5-year-old boy dies from Ebola

CBS News correspondent Debora Patta visited the epicenter of the outbreak in Congo in late May, and said the country's quarter-century-old civil war, and the violence and mistrust it has unleashed, were clearly disrupting efforts to contain the disease. Treatment centers have often been attacked by the myriad militia groups that operate in the region, and many locals were either too scared or too suspicious to seek medical assistance there.

Eastern Congo is home to a myriad of armed groups, and Mai Mai militia fighters are active near the hardest hit towns. Health teams have been unable to access violent areas to vaccinate people at risk of infection and to bring infected patients into isolation.

Other times the violence against health teams has come from residents who do not want their loved ones taken to treatment centers or buried in accordance with guidelines aimed at reducing Ebola transmission.

While the experimental vaccine is believed to have saved countless lives, not all Congolese people have accepted it. Some falsely believe that the vaccine is what is making people sick, in part because people can still develop the disease after getting the shot if they already had been infected.