World Health Organization Director-General Tedros Adhanom Ghebreyesus arrived in Kinshasa, the capital of the Democratic Republic of Congo, late Tuesday to bolster measures aimed at slowing the world’s fastest-growing Ebola outbreak. His visit comes as confirmed cases have reached nearly 4,000.

Ghebreyesus is scheduled to meet with partners and Congolese President Félix Tshisekedi. This marks his second trip to the country since the outbreak was declared on May 15.

According to the latest data released by Congo's Ministry of Health, as of Monday, there have been 3,874 cases, including 1,751 deaths. The current outbreak has surpassed all previous Ebola outbreaks in its transmission rate, making it the second-largest on record, trailing only the 2014-2016 West Africa outbreak, which recorded over 28,000 cases.

The virus responsible for this outbreak, the Bundibugyo virus, does not have an approved treatment or vaccine. Local officials suspect the outbreak may have been active in a remote area of eastern Congo for an extended period before its official declaration.

A significant challenge to containment efforts is that most new cases are occurring outside of monitored contacts, indicating the virus is spreading faster than the expanding response.

In Ituri province, the outbreak's epicenter which accounts for approximately 90% of cases, many areas remain inaccessible due to safety concerns stemming from rebel conflict. Some health workers have reportedly been unpaid, leading to strikes, though recent reports suggest some payments have been made.

Dr. Jean Kaseya, Director-General of Africa Centres for Disease Control, stated on Tuesday during a visit to Bunia, the capital of Ituri province, that contact tracing is proving ineffective, with 60-70% of new cases originating from outside the established contact lists. "We need to be innovative on the way to approach the contact list," Kaseya said.

Officials attribute the 45% fatality rate to the late detection of cases. The health ministry's latest update reported 77 new cases in the preceding 24 hours, which included 44 deaths. Currently, at least 717 patients are receiving care in isolation facilities, while 749 individuals have recovered.