(CNN) -- The World Health Organization is preparing for the "worst case scenario" as it continues to respond to the Ebola outbreak in the Democratic Republic of Congo.
Peter Salama, deputy director-general of emergency preparedness and response at the WHO, said in Geneva, Switzerland, on Friday that it's "going to be tough and it's going to be costly to stamp out this outbreak."
As of Wednesday, 32 people are suspected to have been infected with Ebola viral disease, including three health care workers. Eighteen of those have died, including one of the health care workers.
Of the suspected cases, two have been confirmed as Ebola using laboratory tests, and 10 samples are awaiting results.
"The number of suspected, probable and confirmed cases is significant, so we are very concerned, and we are planning for all scenarios, including the worst-case scenario," Salama said.
Ebola virus disease, which most commonly affects people and nonhuman primates such as monkeys, gorillas and chimpanzees, is caused by one of five Ebola viruses. On average, about 50% of people who become ill with Ebola die.
The disease is endemic to the Democratic Republic of Congo, and this is the nation's ninth outbreak since the discovery of the virus in the country in 1976.
The latest outbreak is occurring in the Bikoro health zone, 400 kilometers (about 250 miles) from Mbandaka, the capital of Equateur province.
Bikoro health zone has a population of about 163,000, with three hospitals and 19 health centers, most with limited functionality, according to WHO.
Given the remote location of the outbreak, Salama said, response efforts will be extremely challenging. "It is a dire scene in terms of infrastructure," he said.
"To give you a sense, we are talking about an area that is 280 kilometers even from the provincial capital of Equateur," he said.
The WHO is working with authorities in Congo and is in discussions with the World Food Programme to arrange airlifting supplies to the affected areas. UNICEF is also making doctors available as well as sanitation and hygiene specialists to help contain the outbreak.
The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission, either through direct contact with bodily fluids such as blood or secretions or contact with materials that are contaminated with these liquids.
Personal protective equipment has been sent to the affected region, and the WHO is planning to have mobile laboratories running by the weekend, after receiving approval from the country's Ministry of Health.
Initial control efforts are focusing on tools such as surveillance and monitoring, safe burials and case management.
Vaccines along with doctors and epidemiologists are on standby in case they are needed, according to the UN.
If they are needed, "WHO is in discussions with the government and, if pertinent, will seek approval from the national regulatory authority and the Ethics Review committee to use vaccines against Ebola as part of the response," spokesman Tarik Jasarevik said.
The current vaccine against Ebola is experimental and not a licensed product. Salama pointed out that its use also comes with many challenges, as the vaccine needs to be stored long-term at temperatures between minus 60 to minus 80 degrees Celsius (minus 76 to minus 112 Fahrenheit).
"This is not a simple logistical effort; it's not like doing a polio campaign with oral polio vaccines, where we get it immediately out to the field. This is a highly complex sophisticated operation in one of the most difficult terrains on Earth," Salama said.
Nine neighboring countries are on high alert, Salama said, but the WHO says the current risk of disease spreading to them is low.
West Africa experienced the largest recorded outbreak of Ebola over a two-year period beginning in March 2014; a total of 28,616 confirmed, probable and suspected cases were reported in Guinea, Liberia and Sierra Leone, with 11,310 deaths, according to the WHO.