An Ebola outbreak has been declared in the Democratic Republic of the Congo (DRC), where three people have been confirmed dead and another six are suspected to be infected with the virus, the World Health Organization has said.

Investigations are still being carried out into how the Ebola virus – which killed 49 people in DRC during a three-month outbreak in 2014 – suddenly occured in the equatorial forest region of Bas-Uele province, which borders Central African Republic (CAR).

In a televised address, DRC’s health minister, Oly Ilunga Kalenga, warned that the outbreak was a “national health emergency with international significance” but urged people “not to panic”.

“As this is the eighth epidemic [of Ebola] that we are facing as a nation, we should not be rattled,” Kalenga said. “The ministry of health is taking all measures to respond quickly and efficiently to this new outbreak.”

The WHO’s in-country spokesperson, Eugene Kabambi, said regional health workers and protective equipment had already been rolled out to the remote area to contain the virus. A national team of personnel, along with experts and specialists from Médecins Sans Frontières, the US Centre for Disease Control, Unicef and WHO, will be following in the next few days.

“The DRC is a big country and the zone affected is quite difficult to access, but it is right on the border with Central African Republic,” said Kabambi. “People are constantly coming and going across the border to visit friends and family, so we are taking very urgent preventative measures to contain the risk.

“We must engage with local communities so they understand that this is a virus unlike any other, it is very contagious and deadly. We are engaging with village heads and community leaders so we can all work together and stop the virus from spreading.”

A conference call between DRC and CAR officials, as well as WHO experts, had taken place, Kabambi said, during which CAR officials confirmed that they too were taking preventative measures along the border.

Of the three people who have so far died of haemorrhagic fever, only one of them has been confirmed by lab results as having Ebola. He was a man who presented himself with a high fever last month at a local clinic and was told to travel to the nearest hospital for tests. Kabambi said he died en route and the motorcycle taxi driver who was drivinghim, as well as another passenger, have also since died of the suspected virus and their deaths were being investigated.

Ebola is fatal in about 90% of cases and is easily spread between humans through direct contact.

The world’s worst Ebola outbreak began in west Africa in 2013 – killing more than 11,300 people and infecting an estimated 28,600 as it swept through Liberia, Guinea and Sierra Leone. Thousands more survivors have been left with long-term health problems and Liberia was only declared free of active Ebola virus transmission last June.

WHO was criticised at the time for responding too slowly and failing to grasp the gravity of the outbreak.

The WHO has recently developed an Ebola vaccine for use in case of an outbreak. Dr Seth Berkley of Gavi, the vaccine alliance, which paired with Merck to develop the vaccine, said clinical trials had proven to be highly successful,

“There are 300,000 doses of Ebola vaccine available if needed to stop this outbreak becoming a pandemic,” Berkley said. “The vaccine has shown high efficacy in clinical trials and could play a vital role in protecting the most vulnerable.”