Health ministry officials are now trying to track down details to avoid the disease from spreading.
Two fatal cases were reported in Uganda last month, marking the first confirmed cross-border cases of the virus in the current epidemic and prompting the WHO's emergency committee to weigh for a third time whether to declare the outbreak an worldwide health emergency.
The ministry said the bus driver and the 18 other passengers will be vaccinated on Monday.
A person infected with Ebola can not spread the disease until they develop symptoms. Many African communities engage in traditional burial practices that require the families to touch the bodies of dead loved ones, however, and in the process of burying an Ebola victim contract the virus themselves.
Goma shares the border with western Rwanda's Rubavu district with daily border crossings between the two countries estimated at about 100,000 people, according to Rwanda's emigration authority. He was taken back to a treatment facility in Butembo on Monday. "DRC's Ministry of Health expressed optimism that Goma would resist the brunt of a full outbreak".
The health ministry said in a statement: "Given that the patient was quickly identified, as well as all the passengers on the bus from Butembo, the risk of the disease spreading in the city of Goma is low". He started showing symptoms last week and was treated at home by a nurse. The workers had been receiving threats for months, the ministry said.
World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus (R) listens to a delegate at the end of a meeting organised the United Nations on the Ebola disease in DRC, on July 15, 2019, in Geneva.
"It's the door of this region to the rest of the world", said Dr. Harouna Djingarey, infectious disease program manager for the World Health Organization's regional office in eastern Congo.
"If we do not get an increase in the funding available, treatment centers are going to close", he said.
Congolese police guard a health center while Ebola vaccinations take place.
An epidemic between 2013 and 2016 killed more than 11,300 people in West Africa. The outbreak took the lives of almost 11,310 people and affected more than 28, 600 individuals mainly from Liberia, Sierra Leone and Guinea. The current one is the second-largest on record after the 2014 outbreak. Ryan told reporters that 60 people who had contact with the preacher had been identified so far.
But the government did not rule out using other vaccines in the future, "once their efficacy has been proven", a government directive to health workers said on Wednesday.