DAKAR, Senegal — The Ebola outbreak in Congo and Uganda has claimed more than 200 lives in its first month and is the worst known outbreak at this stage, with up to 35,000 suspected potential contacts, Africa’s Centres for Disease Control and Prevention said on Thursday.

With 894 confirmed cases so far, the current outbreak is three times worse than a previous outbreak in Uganda in 2000, which had 281 cases at the same point, said Dr. Wessam Mankoula, a medical epidemiologist at Africa CDC.

The latest number of cases is believed to be higher because the outbreak was confirmed on May 15, weeks after it was suspected to have begun. The number of cases has increased 38% since last week and is now in 32 health zones across eastern Congo, said Mankoula.

The outbreak is caused by the rare Bundibugyo virus, which has no approved vaccines or treatments and was not tested for in the early days. The more common Zaire virus, for which there is a vaccine, was responsible for most of Congo’s past 16 outbreaks of the disease.

So far 74 patients have recovered from the disease across eastern Congo and Uganda. Experimental treatments like monoclonal antibodies are being developed for Bundibugyo.

The outbreak is concentrated in Congo’s eastern province of Ituri, which accounts for more than 90% of the cases. Cases have also been recorded in the North Kivu and South Kivu provinces and have spread across the border to Uganda, where 19 confirmed cases have been reported and two people have died.

Contact tracing remains an issue due to the area’s remoteness and ongoing insecurity in Ituri province, Dr. Mankoula said.

“For those 800 confirmed cases, we should have between 17,000 to 35,000 contacts that should be in our contact list,” said Mankoula. Currently only around 4,000 contacts have been tracked and are being evaluated, less than 15%.

“We are still far from controlling the situation of this outbreak,” said Mankoula.

Nearly a million people have been displaced by years of conflict in Ituri, according to the U.N. humanitarian office, making contact tracing difficult as people flee attacks or move frequently in the vast province with dense forests, poor roads and remote villages that can take days to reach.

Tracing is also difficult among the thousands of miners who regularly move among remote sites in the mineral-rich region.

Of the over $900 million pledged to fight the outbreak, only $90 million has been released to help fight the outbreak, further complicating the ongoing crisis, according to Mankoula.

Africa CDC estimates it needs 540 personnel to fight the outbreak and so far they only have 84.

“We’re keeping our fingers crossed those new pledges will be fast tracked, and we’ll be following up with different member states and different partners about their commitment to turn those pledges into actual money released to their affected countries or partners,” said Mankoula.