The fight to cure South Sudan’s mysterious neurological disorder

TThe other children run away in fear as the convulsions begin. Tabo takes a long, throaty breath before falling to the ground unconscious, her entire body shaking. The 17-year-old’s mother, Penina Monyo Gulu Biro, gently holds the girl while the attack lasts.

A minute or two later, Tabo (pictured above) sits up again, tears rolling down her cheeks. “She cries because she is sorry that she is like this,” says Biro.

In 2016, Tabo was diagnosed with nodding syndrome. the neurological disorder that killed her 10-year-old sister Nyibili.

Nodding syndrome was first identified in Tanzania in the 1960s, then in South Sudan in the 1990s and in Uganda in 2007. In the past five years, cases have been reported in the Democratic Republic of the Congo, the Central African Republic and Cameroon. according to Dr. Gasim Abd-Elfarag, an expert on the disease who heads a South Sudanese charity, Access for Humanity.

But South Sudan’s Western Equatoria state, where Tabo’s hometown of Mvolo is located, has the highest prevalence of nodding syndrome in the world, with more than 6,000 cases recorded in health facilities in four of the state’s 10 provinces, according to Amref Health Africa . the aid organization leading the response in the country.

Amref is part of the Nodding Syndrome Alliance (NSA), a consortium of aid groups and universities founded in 2019 that runs research programs and specialized clinics in the provinces of Maridi, Mundri West and Mundri East, which border Mvolo to the south.

  • Tabo Yowan, left, a 17-year-old who has nodding syndrome, with her mother, Penina Monyo Gulu Biro

There is no specialized clinic in Mvolo province, although the area is a hotspot of the disease, with 3,000 cases, according to Lexon Bira, a local coordinator for the Relief and Rehabilitation Commission, a government-run humanitarian organization.

Remote villages have little to no access to anti-epileptic drugs that can help manage symptoms.

The cause of nodding syndrome is still unknown and no cure has been found for the disease, which affects children aged three years and older and persists into adulthood. When it starts, episodes of head nodding are triggered by the sight of food and falling temperatures.

Without anti-seizure medication, the condition worsens, with seizures potentially causing accidents and even death. Long-term effects include brain damage, stunted growth and mental disorders.

Affected children often become socially isolated because they are kept away from gatherings. “Children with nodding syndrome face various types of stigmatization, mainly because there is a lack of understanding of the condition, where it comes from and how it is transmitted,” said Sophia Mohammed, South Sudan director of one of the charities from the NSA, Light for the World, which supports people with disabilities and promotes eye health.

“They often don’t eat with others,” she says. “They are usually kept out of school and those who do attend are often asked to sit apart from the rest of the class.”


Lilian Sebit Doro’s daughter Grace died in 2019. “She died of malaria and chest pain,” says Lilian, who attributes her child’s death to buckling syndrome that weakens her body. Two of her three remaining children also have the disease.

Her daughter, Roda Taban, who is 25, can experience up to “12 seizures in one night,” so Lilian sleeps in the same room to ensure Roda doesn’t accidentally harm her baby if she starts convulsing.

Lilian’s 30-year-old son also suffers from constant seizures and is nearly blind due to onchocerciasis, known as river blindness, a disease caused by a parasitic worm. transmitted by the bite of an infected black fly.

  • Lilian Sebit Doro stands with her grandson in her arms at the grave of her daughter Grace Taban, who died of malaria in 2019. Lilian attributes her death to nodding syndrome, which left her too weak to fight it.

After losing her job as a cook for an international aid organization that ceased operations in Mvolo in 2022, Lilian could no longer afford epilepsy medicine. “I can’t say what the cause of this disease is, whether it is the black fly or the killing of family members,” she says, referring to the local belief that nodding syndrome and epilepsy are a punishment for sharing food with someone who killed your relative without behavior. cleansing rituals.

Researchers have identified a link between nodding syndrome, exposure to black fly bites and onchocerciasis infection. The black fly breeds along fast-flowing rivers, such as the Mvolo River.

Stephen Jada, a physician and researcher at Amref Health Africa, says: “We observed that among communities living near rivers, where onchocerciasis is common, cases of epilepsy and nodding syndrome are more numerous.

“The further you go from the river, the lower the number of cases. And if you go to villages where there is no river, where you don’t see black fly bites, cases of nodding syndrome are rare, if not absent.”

Nodding syndrome is likely a form of “onchocerciasis-associated epilepsy,” says Jada, although he adds, “We don’t know how onchocerciasis could cause the disease.

“Tests have been carried out without success to see if the parasites reach the brain, or if they release a toxin that causes this,” he adds. “This is all still under investigation.”

Several other theories have emerged to explain the increase in cases of nodding syndrome in the region. Spoiled food aid, chemical weapons that could have been used during the civil war and nutritional deficiencies have all been investigated as possible causes, but “no conclusive results emerged,” says Abd-Elfarag.

“It’s still a mysterious disease,” he says. “We are still unable to put the puzzle together and understand its real cause.”


Rresearchers have turned their attention to intervention studies targeting the black fly. These include slash-and-clear operations to remove the grass where the insect breeds. Campaigns to treat onchocerciasis with an antiparasitic drug are now being conducted twice a year by health authorities, after decades of hiatus due to the civil war and the years of instability that followed South Sudan’s independence 13 years ago.

  • Benneth Bare, left, and Julius Sebit Emmanuel volunteer to catch black flies for an onchocerciasis research project

  • Catching black fly, which carries the parasite responsible for onchocerciasis or ‘river blindness’. Researchers have identified a link between nodding syndrome, exposure to black fly bites and onchocerciasis infection

Such interventions have been carried out in northern Uganda, but also recently in the South Sudanese town of Maridi, another hard-hit area in Western Equatoria. have made a difference: The number of new cases of nodding syndrome decreased when both blackfly and onchocerciasis were eradicated.

A similar approach was introduced in Mvolo last year. Sitting on the rocks near the Mvolo River, volunteers spend days catching black flies and trapping them in tubes, recording the numbers collected every hour. The samples will then be sent to the capital Juba and, from May this year, to the University of Antwerp for further analysis and to determine what percentage of black flies carry the parasite responsible for river blindness.


IIn Mundri, a more developed town 100 kilometers south of Mvolo, the NSA’s specialized clinic has registered 1,500 patients since it opened in 2020. Providing free anti-seizure medications has helped reduce the frequency of seizures and episodes of head nodding.

“We have recorded 25 deaths so far, but the majority are now living better lives – they can work or go back to school,” said Joseph Yoto, the clinic’s nurse.

At the Mundri Adventist primary school, only five of the 650 students suffer from nodding syndrome. “There are many more in the community, but parents still refuse to send them to school,” said Rebecca Aunty Ezbon, education officer for the Sudan Evangelical Mission, which trains teachers on how to handle students with the condition.

Lukowe Christine Tina is one of the teachers. “I had that mentality: If I touched a student while they were convulsing, the buckling would transfer to me,” she says.

  • Ninth Bouda, left, a student with nodding syndrome at Mundri Adventist Primary School, with her teacher Lukowe Christine Tina. Bouda is part of the Nodding Syndrome Alliance clinic and project and is successful at school thanks to the support she received

She discovered that the disease was not contagious and was given advice on the best way to respond during seizures. She noticed an improvement in those taking medications provided by the clinic and has become convinced of the potential of her students with the condition.

“Some of them like to play music with traditional instruments, others like debate activities in English,” she says. “We need to figure out where they feel most comfortable to express themselves and thrive in school.”

Ninth Bouda, 19, almost dropped out of school “because she felt scared and ashamed” after having convulsions in class. But the teacher convinced her to return and spoke to her classmates.

Lukowe says: “We had to make them aware: not to run away from her, that this disease cannot affect someone just by interacting with that person. So they understood. And she managed to pass her exams. She is doing well now; she is on her meds and she is free.

Bouda successfully obtained her final exam certificate in December 2023. She calls her teacher her “best friend.”

“I hope to go on and study at university,” she says, “so that I can become a doctor and help the many others with nodding syndrome, as well as those who are blind, those who are disabled, so that they can go back to school, to be strong in their bodies, and to work. People shouldn’t be afraid of them.”

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