It is the fastest-growing Ebola outbreak in history and almost half of the 10,060 confirmed to have the virus have died, according to data from the Democratic Republic of the Congo's health ministry.
That also makes it the deadliest outbreak of the disease in the country's history.
The outbreak declared in May is caused by the rare Bundibugyo virus, for which there is no approved vaccine or treatment.
Response teams are battling armed conflict, poor roads and violence from residents fuelled by mistrust and misinformation.
Those obstacles compound the challenge of persuading people to report symptoms and accept care in communities that have endured years of violence and repeated epidemics.
Compared with the West Africa Ebola outbreak of 2014-16 - history's largest and deadliest with more than 28,000 cases, including more than 11,000 deaths - this has had at least three times the number of cases and number of deaths in the time since it was declared.
It has spread further across Africa than any previous Ebola outbreak, reaching three regions with cases recorded in Kenya and Nigeria as well.
It's so far been recorded in five countries including Uganda and France, both of which have no active cases at the moment.
A recurring problem in the spread in Africa is what appears to be lax surveillance efforts as most of the first cases were confirmed long after people started showing symptoms or after travelling.
In Congo, the disease has spread to 66 health zones across eight provinces, from three zones when it was first declared in May.
Responders have told The Associated Press that they're seeing treatment centres in some of those health zones getting overwhelmed, people still sceptical and violent towards them, and health workers are regularly going on strike to protest delayed or unpaid wages.
In many zones, health workers are battling challenges ranging from basic needs such as adequate vehicles to complex ones like persuading families to release their relatives who are sick with the disease or who have died from it and need to be buried safely.
Last week at the Nia Nia health zone in Ituri province, some Ebola responders, including surveillance and community engagement officers, went on strike over unpaid bonuses owed since late August, a common trend across many affected localities.
More than five months since the outbreak was declared, health workers are still being attacked by angry villagers, including on Saturday when a nurse was killed and another health worker severely injured while responding to an Ebola alert in Bafwasende, Tshopo province.
