GENEVA, July 7 — The Ebola outbreak caused by the deadly Bundibugyo strain in eastern Democratic Republic of the Congo (DRC) continues to expand, with the number of deaths reaching 506, the World Health Organization (WHO) said Tuesday.

WHO representative to the DRC Anne Ancia said the full extent of the outbreak remains unclear and warned that it is too soon to determine whether transmission is slowing. She made the remarks during a briefing in Geneva via video link from Bunia, the capital of Ituri Province, where the outbreak is concentrated.

As of July 4, authorities had recorded 1,561 confirmed Ebola cases in the DRC, including 506 fatalities and 254 recoveries. More than 10,000 contacts are currently being monitored as health officials work to identify possible chains of transmission and contain further spread.

Ancia said Ebola treatment centers are operating at full capacity, while health workers continue providing care despite difficult conditions. She noted that the outbreak is occurring in areas affected by conflict, population displacement and strained healthcare systems.

Although testing capabilities have increased and additional laboratories have been established in affected provinces, WHO warned that shortages of critical supplies remain a major challenge. “Today, we do not have enough ambulances,” Ancia said, adding that the healthcare needs in Ituri Province cannot currently be fully addressed.

The WHO representative also announced that a clinical trial began on July 2 to assess two potential treatments for the Bundibugyo strain. While no officially approved cure currently exists for Ebola, more than 1,200 treatment doses will be used individually or in combination to determine whether they can improve survival outcomes among patients.