A senior health official said clinical symptoms of the victims showed the illness was the haemorrhagic fever Ebola.
"A medical team visited the region to take some samples which will be analysed at the Fraceville Biological Research Centre in Gabon to give us confirmation," Damaze Bozongo, director general of health in the Mbomo region said.
Bozongo said the outbreak occurred in a village called Mbanza.
Five members of a family in Mbanza died after having eaten the meat of a wild boar found dead in a forest by hunters.
The victims showed all the typical symptoms of the Ebola, including high fever, bloody diarrhea, headaches and vomiting.
In 2001 and 2002, more than 100 people died of Ebola in Mbomo and the neighbouring Kelle district.
The virus was apparenmtly transmitted to local tribes people when they ate the flesh of dead gorillas. There is no known cure for Ebola.