(CNN) As health care workers battle a deadly Ebola outbreak in the Democratic Republic of Congo, one important tool has been promising in preventing spread of the virus but can be difficult to carry out: contact tracing.
That's the process of identifying and assessing the health of people who have been exposed to Ebola virus disease, in order to prevent further spread of the virus, according to the World Health Organization.
People who may have been in contact with someone infected with the Ebola virus are followed up with for 21 days after their last exposure in order to determine whether they have contracted the virus themselves. If they become ill, they are isolated to prevent the spread of the virus to anyone else.
"Contact tracing is detective and investigative work, and we do it for the purpose of really containing the virus so it stops spreading," said Chiran Livera, head of the Ebola operation for the International Federation of Red Cross and Red Crescent Societies.
"For any person that is suspected of having Ebola, there's more than about 30 people on average we have to talk to and find. It's a lot of work. It's a lot of volunteers on the ground," Livera said.
"Contact tracing and what we call 'safe and dignified burials' -- so the funeral process -- are probably the two activities we are doing that have the most impact in controlling Ebola," he said, adding that in the current outbreak, "for some of the first cases of Ebola here, many of the people got infected because family members were at the funeral of someone infected."
The Ebola virus can easily spread during burial practices.
The Red Cross is working in partnership with Congo's Ministry of Health and WHO to control the outbreak. In Equateur Province, the Red Cross has launched a team to help conduct burials for those dying of the Ebola virus that are safe but still include some local rituals and customs, such as prayer and sprinkling the body with blessed water.
The efforts illustrate how understanding local needs and cultural practices can be beneficial in overcoming certain obstacles -- such as stigma and fear -- while tracking the virus and preventing any future cases of Ebola virus disease.
"The disease itself can be scary, and then to have a loved one become quite ill and be taken to the hospital or to health care centers is upsetting," said Dr. Anne Schuchat, principal deputy director of the US Centers for Disease Control and Prevention.
"Then the effort to assure that family members and other contacts are OK and that you're following up with them can be challenging," she said. "We learned a lot in West Africa about how important communication was and how really devastating stigma or fear of repercussions could be."
The Ebola outbreak in West Africa between 2014 and 2016 was the largest and most complex on record since the virus was discovered in 1976 near the Ebola River in what is now Congo.
During that outbreak, 28,616 cases of Ebola virus disease and 11,310 deaths were reported in Guinea, Liberia and Sierra Leone. An additional 36 cases and 15 deaths occurred when the outbreak spread outside those countries, according to the CDC.
Many residents in Guinea, Liberia and Sierra Leone saw how those suspected of Ebola infections were whisked away by masked foreigners or quarantined in hospitals where some died and how families were torn apart.
As teams of health care workers and local journalists entered some of the towns most afflicted with Ebola in 2014, they were met by frightened residents who sometimes threw stones at them or chased them away, believing that the workers could be carrying the virus.
There was stigma surrounding the virus, and there was terror.
"Everybody's desire is to end the outbreak as quickly as possible. Everyone's desire is to get the best care for the individuals who are infected and to limit the spread from anybody who is infected. But those competing concerns about fear or stigma -- 'What will happen if I am sick or a family member is sick?' -- you need to address those up front," Schuchat said.
"We don't want people to not report that they're sick, and if you tell people, 'Well, we need you to stay home and not expose other people during this period,' you need to make sure that they have the basics," she said. "If they need to leave their home in order to carry out their livelihood, you need to make sure that they have food and support."
Along with supporting surveillance and contact tracing efforts, the Red Cross has provided support for food, clean water, sanitation and hygiene. For instance, the trade relationships that some communities have with nearby towns have been halted due to fears of spreading the Ebola virus, which could result in a food shortage in some places, Livera said.
Schuchat said that in Congo, "the thing that's new for this outbreak is that the vaccine is being offered to both contacts and contacts of contacts, and so it gives even more value in identifying those close contacts."
Health care workers are administering an experimental vaccine called rVSV-ZEBOV using the ring method: The vaccine is administered to groups of people who have been in close contact with each Ebola case, such as family members or caregivers, as well as the contacts of those contacts.
"The people in the Democratic Republic of Congo are following several hundred contacts of people who had Ebola, and they're checking them every day for three weeks to see whether they in turn develop symptoms. If they do develop symptoms, they're rapidly getting tested and assessed, and if they have Ebola, they're getting treated for that," Schuchat said.
"We're doing surveillance, we're doing contact tracing, and we look for new cases to emerge," she said. "It's both for the contact's benefit to have an early recognition of signs and symptoms so that they can get prompt care, and for the others in the community who would be potentially at risk for exposure."
Therefore, community involvement has become an important component of contact tracing efforts during an Ebola outbreak.
"Local volunteers and health workers are the community's alarm system," Ben Adinoyi, the International Federation of Red Cross and Red Crescent Societies' Regional Head of Health and Care, who is based in Kinshasa, said in a news release last month.
"They are our eyes and ears on the ground. They are critical to the early identification and containment of new cases," he said.