The Ebola outbreak in Congo has passed the grim milestone of 10,000 confirmed cases, prompting concerns among experts about the ability of health authorities to contain its spread. Nearly half of those infected in this outbreak have died, and while some researchers are updating projections, current circumstances suggest a significant impact on most other countries is unlikely. However, approximately 30 confirmed cases have already appeared in nations outside of Congo.
Dr. Jean Kaseya, Director-General of the Africa CDC, stated during a virtual summit that the continent is "not winning" the fight against Ebola and needs to increase efforts after the disease spread to multiple African countries. "Together, we agreed to prepare every country, coordinate across our borders and keep those borders open while watching them closely," Kaseya wrote on X.
Each week, about 400 to 500 new confirmed cases have been reported in Congo, a number that appears to be holding steady. Dr. Boghuma Titanji, an infectious disease specialist at Emory University, noted that while cases are not rising exponentially, they are also not declining, indicating the outbreak is on a high plateau.
A significant challenge in Congo is the limited contact tracing and collaboration with affected communities, with health workers often prioritizing community engagement over direct care. Fewer than a quarter of new cases are identified through known contacts, suggesting ongoing transmission chains that health authorities are not tracking.
As cases continue to mount, the likelihood of infected individuals traveling to other countries increases, according to Titanji and other experts. Cases linked to the Congo outbreak have been reported in France, Kenya, Nigeria, and Uganda. While travel restrictions, such as those implemented by the U.S., can help limit the virus's movement out of Africa, experts believe that health officials in most locations where an infected traveler might arrive would be able to quickly isolate the individual and trace contacts.
Justin Lessler, a University of North Carolina researcher specializing in infectious disease outbreak dynamics, stated that the direct risk to the U.S. is "very close to zero" at this point. However, he noted that Ebola could emerge in regions with weak health systems, such as South Sudan, which are often affected by poverty and conflict.
Viruses that cause Ebola disease are transmitted through contact with bodily fluids like vomit, blood, and semen. Since the disease was first identified in 1976, dozens of Ebola outbreaks have occurred. The largest and deadliest took place in West Africa from 2014 to 2016, resulting in 28,000 infections and over 11,000 deaths. The current outbreak already ranks as the second-largest and has seen at least three times the number of cases and deaths in a comparable timeframe to the West Africa outbreak. Although the outbreak was declared in May, medical evidence suggests infections began occurring months earlier.
Several factors have complicated the response, including armed conflict in some outbreak zones, systemic gaps in healthcare, mistrust and misinformation within communities, and reductions in global aid. The varying conditions across Congo contribute to the uneven spread, with cases stable or declining in some areas while rising in others.
"Testing, care and contact tracing only work if we work with communities, going door to door, village by village to break the chain of transmission and stop this deadly escalation," said Katie Thomas-Canfield, the International Rescue Committee’s Ebola response director.
Dr. Wendy Armstrong, president of the Infectious Diseases Society of America, expressed concern that the situation is likely to worsen, stating, "This is very far from being controlled."
Experts anticipate the outbreak will persist through the end of the year. However, Titanji expressed optimism for 2027, citing the ongoing testing of vaccines against the Bundibugyo virus and the potential availability of an effective vaccine within the next 12 months. She highlighted that no vaccines were available at the start of the 2014-2016 West Africa outbreak.
Forecasting the outbreak's trajectory remains challenging. In May, the U.S. Centers for Disease Control and Prevention (CDC) released model-generated scenarios estimating that case growth over three months could range from 10,000 to over 20,000, when the Africa CDC reported 400 confirmed cases. The CDC is updating its modeling but declined to provide interviews with its scientists regarding the outbreak's trends to The Associated Press.
Alessandro Vespignani, a disease modeler at Northeastern University working with U.S. and international health officials, noted a lack of the necessary "decay in the number of cases weekly that we need to see the light at the end of the tunnel."