Health minister says up to 15 people may have died but virus is not linked to epidemic that has spread through west Africa

The World Health Organisation has sent protective equipment for medical staff to the Democratic Republic of the Congo after it became the fifth African country this year to suffer a deadly outbreak of Ebola.

"The ministry of health has declared an outbreak and we are treating it as such," Tarik Jasarevic, a WHO spokesman, told Reuters in Geneva on Monday.

Congo declared on Sunday that Ebola had been identified in its northern Équateur province after two patients tested positive for the virus, but the health minister, Felix Kabange Numbi, denied any link to the epidemic raging in west Africa.

Officials believe Ebola has killed 13 other people in the region, including five health workers. Kabange said 11 were ill and in isolation and 80 contacts were being traced, and the Djera area would be placed under quarantine. Djera is about 750 miles (1,200km) from Congo's capital, Kinshasa, and 375 miles from the provincial capital, Mbandaka.

Ebola has swept through Liberia, Guinea, Sierra Leone and Nigeria, resulting in 1,427 deaths and 2,615 infections since March. But Kabange said the Congolese epidemic "has nothing to do with the one in west Africa".

One of the two cases that tested positive was for the Sudanese strain of the virus, he explained, while the other was a mixture of the Sudanese and the Zaire strain – the most dangerous. The virus in west Africa is the Zaire strain.

A Liberian soldier scans people for signs of Ebola infection as part of quarantine measures in Monrovia. Photograph: Abbas Dulleh/AP

Ebola was first identified in 1976 near the Ebola river in Congo and this is the seventh outbreak since. "The experience acquired during the six previous epidemics of Ebola will contribute to the containing of this illness," Kabange said.

Médecins Sans Frontières said it was sending a crew to help handle patients in the Djera area.

A Liberian doctor treated with an experimental Ebola drug, ZMapp, died late on Sunday, the country's information minister said yesterday.

Dr Abraham Borbor, the deputy chief medical doctor at Liberia's largest hospital, had received the untested drug after it was given to two American health workers, who survived after receiving medical care in the US.

A Spanish missionary also received the treatment but died. Two health workers are still in treatment, and there were "signs of hope", said Kabange.

Japan has said it is ready to offer another experimental drug developed by a Japanese company to help stop the epidemic. Avigan was approved as an anti-influenza drug in Japan in March, and its developer Fujifilm Holdings said it had received inquiries about its use against Ebola. "Our country is prepared to provide the yet-to-be approved drug in cooperation with the manufacturer if the WHO requests," said chief cabinet secretary Yoshihide Suga.