At least 25 people have died and 38 believed to be infected in district previously unaffected by virus

The leader of a remote chiefdom in Sierra Leone has called for urgent help to contain Ebola, which is causing fear and panic in his community.

The fresh outbreak of Ebola in Koinadugu, a district previously unaffected by the virus, has affected more than 60 people in a small chiefdom close to Guinea, the Red Cross has said.

The head of Sierra Leone’s Red Cross team, John Mara, told the Guardian that at least 25 people had died and 38 people were believed to be infected after lab results proved positive for 15 more patients. Two of those buried had died on Tuesday, including a seven-year-old girl.

Koinadugu had prided itself on being the only district in Sierra Leone to have been Ebola-free after local chiefs imposed a quarantine, barring travel and creating a system of official distribution vans and trucks to help farmers and traders get their product to neighbouring markets.

However, after two unexplained deaths in October were investigated, it emerged that Ebola had reached the chiefdom of Nieni and its three villages of Fankuya, Sumbaria and Kumala.

The Red Cross met chief Foday Jalloh, the paramount or head chief of Nieni, to get his permission to enter the region to help the community, where traditional burial practices and medical therapies may have contributed to the spread of the virus. Jalloh said: “Please help us, we need your help and support.”

Mara, who is from the area, said: “We discovered there had been 25 deaths already, some of them unexplained. Prior to this, the district went six months without Ebola. On 15 October there were two cases of unidentified deaths. The situation is not really good because we have just got the results that show there are 15 new cases, on top of 23 we already knew about.”

A Red Cross spokesman said it sent two burial teams to help local volunteers. However, the rugged terrain is making access difficult. “It’s about five hours’ drive to the district Kabala and then another five hours to the Nieni chiefdom. Our Toyota Land Cruiser got stuck twice yesterday on creeks and streams. Sometimes the bridge is just two logs for the right-hand and left-hand-side wheels,” he said.

He said there was evidence the infection rate had dropped significantly in Kailahun, where the burial teams had come from. It was at the centre of the first outbreak in June and the site of the first field hospital erected by Médecins sans Frontières. “There were about 400 new cases a week in the peak in August. It has come down to five or 10 in the last few days,” said the spokesman.

An estimated 70% of infections emanate from funerals, when highly contagious corpses have been washed in a traditional manner by friends and family.

The Red Cross said education and community training about the dangers of traditional burial practices in Kailahun and Kenema, a nearby commercial hub, appeared to be paying off.

“But we need to have zero new cases for 21 days before we can say it is clear of Ebola and all it takes is one case for it to start again,” said the spokesman.

The apparent slowdown in the east is countered by the continued growth of the disease in Freetown, where there are now more than 60 burials a day and a chronic shortage of treatment beds and health workers to staff them.

A UK-funded Ebola hospital outside the capital in Kerrytown hospital opened on Wednesday, adding 80 treatment beds and a 12-bed unit manned by the British army specifically for health workers infected by the disease.

The scale of the crisis has left Sierra Leone with a severe shortage of beds to treat Ebola patients. The World Health Organisation estimates that there are only 326 treatment beds in Sierra Leone but that up to 4,800 could be needed by the end of November.