By Tom Miles and Fiston Mahamba
It may be impossible to use a vaccine to tackle Democratic Republic of Congo's new Ebola outbreak that has caused four confirmed cases, including two health workers, a senior World Health Organization (WHO) official said on Thursday.
Officials have not confirmed the particular strain of Ebola causing the outbreak, which may have killed 20 people, but WHO's emergency response chief Peter Salama said it could be the Zaire, Sudan or Bundibugyo strain.
If it is the Zaire strain, the Merck vaccine used in the last Ebola outbreak may be an option, otherwise the situation will be much more complex "and we may not have any vaccine options", he told Reuters at WHO's headquarters in Geneva.
"The majority of the cases occurred in the second half of July ... When the provincial medical teams have looked back ... they have noted cases that could be consistent with Ebola that began even in May but it’s far too early to say," Salama said.
The cases are spread over tens of kilometers, he said.
International experts set up a laboratory on Thursday in the city of Beni, 30 km (18 miles) from where the outbreak was declared, WHO and Congolese officials said.
Officials from the United Nations, World Bank, WHO Congo's Ministry of Health, including Health Minister Oly Ilunga, will support a team already on the ground.
Congo declared the outbreak on Wednesday, just days after another that killed 33 people in the northwest was declared over.
The 20 died in and around Mangina, a densely populated town in North Kivu province about 30 km (18 miles) southwest of the city of Beni and 100 km from the Ugandan border.
The ministry has not made public when the deaths occurred. Another six who are still living are showing signs of fever, of which four tested positive.
"The Government-Partner delegation is holding its first meeting to organize the response," North Kivu governor Julien Paluku tweeted. "Already a ... team from Kinshasa is installing a laboratory and a single coordination center."
But eastern Congo is a tinderbox of conflicts over land and ethnicity stoked by decades of on-off war and this could hamper efforts to contain the virus.
About 1,000 civilians have been killed by armed groups and government soldiers around Beni since 2014, and the wider region of North Kivu holds over 1 million displaced people.
"The response is already in place," David Gressly, United Nations Deputy Special Representative Congo, told journalists in Beni. "We (the U.N. mission) will offer logistical support and if needed security support. We are all ... here to see how we can organize this as fast as possible."
(Additional reporting by Elias Biryabarema in Kampala; Writing by Tim Cocks; editing by Matthew Mpoke Bigg)