Authorities in Guinea are concerned about a new outbreak of cases just as officials hoped the crisis was coming under control.
The country where the Ebola epidemic began has recorded 27 new cases in a week, compared with seven the previous week, according to the World Health Organisation.
Health officials are particularly alarmed that some of the cases are in an area near the border with Guinea-Bissau, a deeply impoverished country with very few functioning health care centres.
Sakoba Keita, who heads Guinea's anti-Ebola effort, said the country had been "close to victory" over Ebola, and the new cases mark a setback.
The Ebola epidemic began in Guinea in December 2013 and spread to neighbouring countries. Only Guinea and Sierra Leone are still reporting cases in west Africa.
Relatives of Ebola victims are reported to be transporting their bodies on public transportation in Guinea, seating the corpses upright between other passengers to skirt health controls and contributing to the spread of the disease.
Bodies of victims are highly contagious, yet the health recommendations to not touch bodies at funerals go against hundreds of years of tradition here. Family members still want to give their loved ones traditional burials to prepare their souls for the afterlife, and some even try to transport the bodies to their home villages if they died elsewhere.
"It is regrettable that some families with the help of transport providers are dressing up cadavers and seating them upright between other passengers in a taxi as though the person is still living when in fact it's sometimes the body of someone who has died from Ebola," said police Captain Claude Onivogui.
"Every day we are finding bodies in these conditions, and that's what is spreading the contagion."
The latest Ebola figures are the highest in Guinea in more than a month. Neighbouring Liberia has been declared Ebola-free and Sierra Leone registered only eight cases during the same period.
It is against the law to transport bodies of Ebola victims from one community to another. However, Rabiatou Serah, a member of an anti-Ebola committee, said the relatives who are concealing bodies are managing to get past inspection agents.
Eleven of the 27 new cases were reported in Dubreka, and authorities believe the people who fell sick had come in contact with those who attended the funeral of an Ebola victim in mid-April. Suspicion of outsiders has complicated the efforts of teams trying to investigate.
"Difficulty engaging local communities has made case investigation and contact tracing in the area challenging," the WHO said in its update.
More than 11,000 people have died since the Ebola epidemic emerged in the forests of south-eastern Guinea in December 2013, including more than 2,400 in Guinea.