The number of suspected Ebola patients in Guinea has more than doubled from last month, the health ministry said on Thursday, highlighting a "fourth phase" of the epidemic after a dip in cases in early 2015.
The worst outbreak in history, which has killed more than 10,000 people in West Africa, appears to be on the wane, especially in Liberia where there are no current cases.
But there is still resistance to the anti-Ebola effort in Guinea, which is struggling to control the outbreak and has overtaken Sierra Leone as the main hub for transmission.
Dr Rafiou Diallo, a spokesman for Guinea's health ministry, said there were 91 suspected and confirmed Ebola patients in treatment centers compared with just 39 in February.
"There is without doubt a spike in the number of cases, especially in Forecariah and Coyah (western Guinea). The explanation is there is still resistance that has not been overcome," he said.
The number of Ebola cases in Guinea peaked in late December when there were nearly double current number of patients at 171, according to the World Health Organisation.
The current Ebola outbreak was first confirmed in Guinea's remote southeastern forest region last March.
From there, it spread across the country and into neighboring states. Liberia and Sierra Leone were worst hit but Mali and Senegal also recorded cases.
Guinea's President Alpha Conde has set mid-April as the target for completely ending the epidemic. Officials in Guinea have previously said Ebola was under control, only to see the virus later spread further.
"Officials are calling this the fourth phase of the epidemic characterized by an increase in cases following the dip in January," Dr. Jean-Pierre Lamarque, regional health adviser for the French foreign ministry, said by telephone from Guinea.
The first phase was characterized by scattered cases in early 2014, followed by a spike in transmission in the forest region last summer and finally an ebbing in cases in early 2015.
Unlike Liberia and Sierra Leone, the other two worst hit nations where U.S. and British military forces deployed to support the fight against Ebola, Guinea has not seen a large scale foreign military intervention.