Thirty five new Ebola cases in Guinea and Sierra Leone were reported in the past week, four times as many as the week before, in a reminder that the virus "will not go quietly," a top World Health Organization (WHO) official said on Tuesday, Reuters reported.
After Liberia was declared free of Ebola earlier this month, there was hope that the Ebola would come to a complete end soon.
Unsafe burials of Ebola victims in Guinea contributed to the rise in new infections.
Most of the new cases, about 27,occurred in Guinea, and one area in particular is a problem spot: the Forecariah district southeast of the country’s capital, Conakry. It is far from where the outbreak started, in Guinea's Forest Region, but it is in an area where there has been resistance to the sanitary burials.
"We've been concerned about a number of cases coming from there, of people dying in the community," said Dr Margaret Harris, a spokeswoman for the WHO, referring to the failure to turn corpses over to the authorities in Ebola hot spots - a refusal that has bedeviled health officials since the beginning of the outbreak.
"There is still some concern that there are unsafe burials going on," she said. "The burial issue is still a very tough one."
Dr Harris said a team of experts had been sent to the Forecariah area to help combat the spread of the disease.
"It doesn't surprise us that within the tail of the epidemic there are peaks and valleys," said Brice de la Vigne, the Brussels operations director of Doctors Without Borders, which has led the response to the epidemic over the last 14 months.
"This is not scaring us beyond reason; it is normal," Dr de la Vigne said, but "we know that there are still people who are contaminating themselves at funerals."
In Guinea, resistance to the intervention of outsiders - doctors, health officials, politicians - has been stronger than in either Sierra Leone or Liberia.
Guinea has reacted with occasional violence to efforts to contain the disease. In the Forest Region, eight officials and journalists were killed by villagers during an anti-Ebola rally in September.
More than 11,000 people have died of Ebola in the three countries, and there have been over 26,000 confirmed, probable, and suspected cases according to the WHO's latest situation report on the epidemic.