The study, led by Daan van der Vliet, focused on brain tissue from patients with severe forms of MS.
The researchers discovered large numbers of immune cells known as microglia that had accumulated fat droplets after absorbing damaged myelin, the protective layer surrounding nerve fibers in the brain and spinal cord.
Myelin is essential for efficient communication between nerve cells. In MS, the immune system attacks and damages this coating, leading to a range of neurological symptoms such as vision problems, difficulty walking, and in advanced cases, paralysis.
However, the disease does not progress in the same way for all patients, and scientists have long sought to understand the reasons behind these differences.
In affected brain regions, the researchers observed that microglia became overloaded with fat, giving them a “foamy” appearance.
These cells normally help maintain brain health by clearing away damaged material and supporting repair. However, when overwhelmed by large amounts of myelin debris, they appear to change behavior.
According to the study, patients with a higher presence of these “foamy microglia” were more likely to experience a severe and rapidly progressing form of MS. This suggests that the buildup of fat within these immune cells may be linked to worsening disease outcomes.
Further analysis showed that brain lesions containing foamy microglia had distinct molecular characteristics compared to those without them.
These areas were enriched with specific types of fats associated with ongoing inflammatory activity, indicating that the process may contribute to sustained inflammation in the brain.
Researchers explain that while microglia are initially intended to protect the brain by clearing damaged tissue, they may become dysfunctional when overloaded.
Instead of supporting repair, these cells may lose their effectiveness and contribute to continued inflammation and tissue damage.
The findings suggest that MS progression may not be driven by inflammation alone, but also by a breakdown in the brain’s natural repair system. When this system becomes overwhelmed, it may unintentionally contribute to further damage.
Scientists say the discovery could open new research directions, including the development of biomarkers that help predict disease progression and potential strategies to prevent immune cells from becoming overloaded.
While further studies are needed, the research provides important new insight into the complex mechanisms behind multiple sclerosis and how the brain’s own immune cells may play a dual role in both repair and damage.
Study suggests overloaded brain immune cells may intensify multiple sclerosis damage.
The outbreak has been reported in the eastern provinces of Ituri, North Kivu, and nearby areas. Health authorities report a case fatality rate of 26.7%.
So far, 148 patients have recovered and returned to their families, while 326 others remain under medical care in designated treatment centres. Between 24 and 25 June, health teams screened 1,175 people showing symptoms similar to Ebola, while 142,503 travellers were tested at border points.
Authorities also report progress in contact tracing, which has now reached 82.8%. This improvement is expected to strengthen efforts to contain the spread of the virus.
The outbreak was first declared on May 15 in Mongbwalu, in Ituri. This marks the 17th recorded Ebola outbreak in the country, and one of the most significant in recent years.
The current outbreak is caused by the Bundibugyo strain of Ebola, which has also spread to Uganda, where 20 cases have been confirmed, including two deaths. In France, one case has also been reported, involving a doctor who recently travelled from eastern DRC.
The World Health Organization (WHO) has warned that the Bundibugyo strain poses a serious international concern, noting that there is currently no confirmed treatment or vaccine for it.
Officials further stress that ongoing conflict and insecurity in eastern DRC are making response efforts more difficult, as medical teams struggle to access affected areas. Limited public awareness in some communities is also slowing down efforts to control the outbreak.
Over 1,200 Ebola cases have been confirmed in the DRC, with 321 deaths reported.
“There is no Ebola here. No one is dying here. But people are now dying because they are unable to travel abroad for medical treatment,” Francis Oromo, undersecretary in the Ministry of Health, told a joint press conference with the World Health Organization (WHO) in Juba, the capital of South Sudan.
According to Oromo, South Sudan activated its emergency response plan immediately after outbreaks were reported in neighboring countries by deploying response teams to high-risk states, strengthening surveillance, and expanding isolation capacity.
The ministry noted that all seven suspected Ebola cases identified nationwide, including four in Juba, tested negative.
As South Sudan remains at risk due to cross-border movement and its proximity to affected areas, health authorities are collaborating with neighboring countries, regional health bodies, and international partners to share information and strengthen disease surveillance.
Humphrey Karamagi, WHO representative in South Sudan, reaffirmed that the country remains Ebola-free, saying the detection and investigation of suspected cases demonstrate that the national surveillance system is functioning effectively.
“From a scientific point of view, WHO does not recommend border closures or travel restrictions,” Karamagi added.
Dr. Oromo Francis, Undersecretary at the Ministry of Health, and Dr. Humphrey Karamagi, WHO Representative in South Sudan, during a press conference in Juba on Ebola preparedness on Friday, June 26, 2026.
An update released Wednesday by the government showed that 122 people have recovered, while 408 patients are under care. The fatality rate stood at 26.0 percent. Epidemiological surveillance remains active, leading to the identification of 138 suspected cases. The contact follow-up rate stood at 77.1 percent.
The latest figures came as WHO officials said the response had made visible progress in recent weeks, but remained constrained by insufficient contact tracing, limited treatment and isolation capacity, challenges in safe burials, insecurity and weak humanitarian access in the affected eastern provinces.
WHO Director-General Tedros Adhanom Ghebreyesus told a press briefing in Geneva that the Ebola response had “scaled up significantly” under the leadership of the DRC government since the outbreak was first reported five weeks ago.
According to Tedros, treatment capacity has increased from fewer than 10 beds to more than 500 beds across 19 health centers, while laboratory capacity has risen from about 30 tests a day at the central laboratory in Kinshasa to more than 2,000 tests a day across nine laboratories in three provinces.
Tedros noted that early detection and supportive care can save lives. But he cautioned that “the outbreak is continuing to outpace the response.”
“Contact tracing is still not at the level needed. Capacity at treatment and isolation centers is insufficient. Safe and dignified burials remain a major challenge. The health system is under pressure,” he said.
In neighboring Uganda, Tedros said a new case was reported on Sunday, the first in two weeks, bringing the country’s total to 20 confirmed cases and two confirmed deaths. All cases in Uganda are linked to the outbreak in the DRC.
Marie Roseline Belizaire, WHO regional emergency director for Africa, said at the briefing that each confirmed case could have between 120 and 200 contacts based on previous experience, while some community deaths could generate even larger numbers.
The challenge is particularly acute in Mongbwalu, in Ituri province, the mining area considered the epicenter of the outbreak, where many patients are young men who travel from different provinces in search of work and may move again when they become ill.
Chikwe Ihekweazu, executive director of the WHO Health Emergencies Programme, said the response was in “a much better place” than four weeks ago, but “nowhere where we need to be.”
Tedros also said preparations had been completed for a clinical trial expected to start in the DRC next week to evaluate whether two antivirals, MBP134 and remdesivir, can reduce mortality among patients with Bundibugyo virus disease, either alone or in combination. The current outbreak is caused by the Bundibugyo Ebola virus, for which there is no approved vaccine or specific treatment.
Vasee Moorthy, senior adviser in the office of the WHO chief scientist, said about 1,000 participants would need to be involved. “It means that we are looking at around 1,000 that would need to be enrolled in the trial before we expect that there will be an answer about the safety and efficacy of any of these options.”
France reported Wednesday its first confirmed Ebola case after a humanitarian worker tested positive upon returning from the DRC. France has identified and isolated five people who may have been exposed to Ebola after sharing a flight with the health worker.
The patient is an “experienced doctor returning from a mission” who was unaware that he had contracted the virus, said French Health Minister Stephanie Rist. “He had no symptoms when he boarded the plane, and he was not contagious (…) As he is a doctor and developed headaches on the plane, he raised the alert” so that he could be taken care of upon arrival in Paris, Rist noted.
The man was placed in isolation at a hospital as soon as his flight landed. He will remain there “for 21 days, the duration of the incubation period,” Rist added. The incubation period for Ebola is typically between two and 21 days.
In a statement on Wednesday, the DRC government said the doctor had been deployed by the humanitarian organization ALIMA and worked from May 22 to June 19 at an Ebola treatment center in Rwampara, Ituri province, one of the epicenters of the outbreak, where he served as an “intensive-care” physician.
After completing his rotation, he left Ituri on June 19 and transited through the capital, Kinshasa, where he stayed until June 22 before traveling to France on June 23, said the statement.
The statement also stressed that a person infected with Ebola “becomes contagious only after the onset of symptoms,” and that the disease is transmitted only through direct contact.
Abdirahman Mahamud, director for WHO’s Health Emergency Alert and Response Operations, said the patient was “doing well,” with “mild symptoms and fever.” He praised the French authorities for taking rapid action and said the risk to France and the global population remained low.
The global risk posed by the ongoing Ebola outbreak in Africa remains low despite rising case numbers in the affected region, said Tedros. He also urged against panic, saying Ebola cases detected outside Africa had remained below 30 in the past 50 years.
“No need for panic,” Tedros said. “The risk is low. I repeat, the risk is low.”
The French case nevertheless underscores the risks faced by frontline responders. Tedros said over 80 health workers had been infected while responding to the outbreak.
The Democratic Republic of the Congo (DRC) on Wednesday reported 1,118 confirmed Ebola cases, including 291 deaths, as the WHO warned that the outbreak continues to outpace the response.
The patient, a doctor who recently returned from an Ebola-affected area in the Democratic Republic of the Congo (DRC), tested positive for the virus, Le Parisien reported, citing the French Ministry of Health.
The patient was immediately transferred to a specialized medical facility and is currently in stable condition, the ministry said.
The DRC has reported 1,094 confirmed Ebola cases, including 277 deaths, in the current outbreak declared on May 15, with the World Health Organization registering a record first-month caseload.
The patient, a doctor who recently returned from an Ebola-affected area in the Democratic Republic of the Congo (DRC), tested positive for the virus, Le Parisien reported, citing the French Ministry of Health.
The declaration, adopted by a vote of 149 in favor, eight against, and 14 abstentions, expresses deep concern that the world did not meet the global 2025 HIV targets and is not on track to end AIDS as a public health threat by 2030.
It reaffirms the 2001 Declaration of Commitment on HIV/AIDS and the political declarations on HIV/AIDS adopted in 2006, 2011, 2016 and 2021, as well as the target set in the Sustainable Development Goals.
The declaration commits to urgent action over the next five years, through a coordinated, evidence-based and people-centered global HIV response; commits to strengthen country leadership and ownership and ensure integrated, people-centered multisectoral national HIV responses to ensure services and impact beyond 2030.
According to the declaration, the UNGA will convene a high-level meeting on HIV/AIDS in 2031 to review progress on the commitments made in 2026 toward the goal of ending AIDS as a public health threat by 2030 and sustaining it into the future.
“This political declaration is our chance to build on 25 years of commitment and point the way to 2030 to show that multilateralism can deliver,” said Winnie Byanyima, executive director of the Joint United Nations Programme on HIV/AIDS (UNAIDS), at the opening of the meeting on Monday.
“We cannot fail, because we know what we must do: commit to multilateralism; sustain international financing as countries mobilize their own resources; protect the rights of people living with HIV; let communities lead for their people; and spur the science, so that innovations reach everyone in need as fast as possible,” she said. “If we do these things, we can end AIDS.”
Data from 2025 released by UNAIDS show that sustained investment, scientific advances and community-led efforts have led to tremendous success against AIDS. Since 2010, AIDS-related deaths have fallen by 56 percent, new HIV infections decreased by 43 percent, and 32.1 million people (78 percent of the 40.9 million people living with HIV) are now accessing treatment.
The declaration, adopted by a vote of 149 in favor, eight against, and 14 abstentions, expresses deep concern that the world did not meet the global 2025 HIV targets and is not on track to end AIDS as a public health threat by 2030
Official data released Tuesday showed 387 cases were under quarantine or receiving treatment, and 115 recoveries. DRC authorities have also reported 131 suspected cases, including 44 suspected deaths.
In its daily epidemiological report, the health ministry noticed an increase in confirmed cases on a weekly basis, consistent with ongoing community transmissions.
It said intensified public health measures, including stronger epidemiological and laboratory surveillance as well as the decentralization of diagnostic capacity, have contributed to earlier detection, confirming expanded community transmission.
“This is the largest number of confirmed cases in the first month of an Ebola disease outbreak in Africa,” Abdirahman Mahamud, director of Health Emergency Alert and Response Operations at the WHO, told a press briefing in Geneva on Tuesday.
Mahamud pointed to encouraging signs that the response was expanding to keep pace with the spread. Treatment capacity has increased over the past two weeks, “going from a handful to over 500 beds across 19 health zones,” he said.
Laboratory capacity has also been sharply expanded, from around 30 tests per day in the capital Kinshasa at the start of the outbreak to more than 2,000 tests per day through a network of eight decentralized laboratories across Ituri, North Kivu and South Kivu provinces, he said.
DRC President Felix Tshisekedi said Tuesday that he would soon travel to Ituri province, the epicenter of the outbreak, to follow up on response operations on the ground.
He made the remarks at a joint press conference in Kinshasa with visiting Burundian President Evariste Ndayishimiye, whose country currently holds the rotating presidency of the African Union.
Prior to the press conference, the two leaders were briefed on the DRC’s epidemiological situation and response measures at a meeting with the Central African country’s national Ebola response task force.
To contain the Ebola outbreak, Tshisekedi also called for stronger regional cooperation based on prevention, epidemiological surveillance and rapid information-sharing.
Ndayishimiye urged African countries and the wider international community not to close borders.
Uganda, which borders the DRC’s Ituri province that has accounted for about 90 percent of the infections, has confirmed one more Ebola case, bringing its total number of confirmed cases to 20, including 14 recoveries and two deaths, showed the latest data from its health ministry.
Fifteen of the reported cases were imported, it said.
Also on Tuesday, Uganda and the DRC launched cross-border collaboration to fight the Ebola outbreak, covering shared surveillance and joint deployment of rapid response teams, mobile laboratories, and Ebola treatment centers.
According to a WHO update released on Friday last week, the Ebola-related health risk in the DRC remained very high because of ongoing transmissions and continued expansion of the outbreak into new health zones, increasing the potential for further national and regional spread.
Meanwhile, the risk in Uganda remained high due to confirmed cross-border spread through imported cases and the epidemiological links along the eastern DRC-western Uganda corridor.
Official data released Tuesday showed 387 cases were under quarantine or receiving treatment, and 115 recoveries. DRC authorities have also reported 131 suspected cases, including 44 suspected deaths.
“This is a meeting that is taking place to find solutions, and once again summon the political will to accelerate and finish the global HIV fight,” Guterres said in a statement delivered by UN Deputy Secretary-General Amina Mohammed at the Opening Plenary of the High-level Meeting on HIV/AIDS.
Guterres said that in the 45 years since the first case of AIDS was reported, the world has demonstrated uncommon resolve and solidarity, which “wasn’t easy.”
Thanks to the political commitment and resolve shown by governments and investments by global partners, AIDS-related deaths have been reduced by 70 percent since their peak in 2004, and by 54 percent in 2010, he said.
According to the secretary-general, HIV prevention and treatment services have reduced new infections by 40 percent since 2010, and today more than 32 million people living with HIV are receiving lifesaving antiretroviral therapy.
However, “AIDS is not over,” with 9.2 million people in need still lacking access to HIV treatment at the end of 2024, said Guterres.
He proposed five “essential” acceleration pathways: closing the widening gaps in access to prevention, treatment and care services; continuing to ensure the leadership of communities in the HIV response; protecting human rights; securing financing; and reviving the multilateral spirit that has driven the HIV response from the very start.
“The HIV response has shown that solidarity across borders and sectors can overcome fear, inequality and injustice. And it has proven that global, regional and local institutions are all essential to deliver together,” he said.
Noting that the meeting is a chance to demonstrate that the international community can rally once again around science, human dignity, solidarity and shared responsibility, the UN chief said that “the responsibility to end AIDS as a public threat by 2030 belongs to each and every one of us.”
UN Secretary-General Antonio Guterres on Monday called for political will to accelerate and finish the global HIV fight at a high-level meeting of the UN General Assembly.
According to the report, covering data as of Sunday, 371 patients were in isolation or hospitalized, while 112 people had recovered. A total of 202 suspected cases, including 60 deaths, were identified as of Sunday. The overall case fatality rate stood at 25.5 percent.
The report said the number of confirmed cases has continued to rise week by week, indicating ongoing community transmission. It warned that a rapid geographic spread remains possible if public health measures are not implemented promptly.
The current outbreak, caused by the Bundibugyo ebolavirus, was officially declared on May 15 by the DRC’s health ministry.
Red Cross workers bury an Ebola victim at the Rwampara Cemetery, in Rwampara, Congo, Saturday, May 23, 2026.
According to figures released by the DRC health ministry, the country has reported 1,003 confirmed cases, including 254 deaths, with an overall case fatality rate of 25.3 percent.
A total of 365 patients are currently in isolation or hospitalized, while 100 patients have recovered, the update said. The contact follow-up rate across the three affected provinces stood at 58 percent.
Despite the rise in cases, Ebola response efforts remain active, with heightened surveillance, intensified community outreach, and ongoing efforts to strengthen case management and diagnostic capacity, authorities said.
Red Cross workers bury an Ebola victim at the Rwampara Cemetery, in Rwampara, Congo, Saturday, May 23, 2026.
