GULU, Uganda — A scientist at Uganda’s Gulu University is investigating a possible link between mould-contaminated maize and Nodding Syndrome, a neurological disorder that has affected thousands of children in northern Uganda.
Dr Richard Echodu, Director of Gulu University’s Multifunctional Research Laboratories, says preliminary laboratory experiments have found that rats fed maize contaminated with certain types of mould developed repetitive head movements and seizure-like symptoms resembling those experienced by people with the condition.
The findings have raised a new research question about whether substances associated with fungal growth in food could contribute to the neurological disorder, whose exact cause remains unknown despite years of scientific investigations.
However, Echodu cautions that the results are preliminary and do not establish that eating mouldy maize causes Nodding Syndrome in humans.
The research, which he has pursued since 2008, has recently focused on identifying possible causes beyond Onchocerca volvulus, the parasite responsible for river blindness that has repeatedly been associated with the syndrome.
Experiments point to possible food contamination link
Echodu said the latest investigation was conducted with a Japanese PhD student and began about a year ago, with researchers collecting mould samples from maize gardens in Omoro, Pader and Kitgum districts.
The districts are among areas in the Acholi sub-region that have reported cases of Nodding Syndrome.
Laboratory analysis found elevated levels of certain amino acids in maize contaminated with particular types of mould, prompting the team to investigate whether the substances could affect the nervous system.
To explore the possible relationship, the researchers conducted experiments involving four to five laboratory rats, divided into two groups.
One group was fed mould-contaminated maize, while the control group received maize confirmed to be free from mould. The researchers then monitored the animals for behavioural changes and symptoms.
According to Echodu, the rats that consumed the contaminated maize developed repetitive head-nodding movements and seizure-like behaviour, while the control group was used for comparison.
“When we gave the rats the mouldy maize, they started exhibiting symptoms similar to nodding. That is where we established a very close association between eating this mould-contaminated maize and the symptoms,” Echodu told Vivid Voice News.
The scientist said the observations provided a new lead for further investigation but stressed that the team had not established how much contaminated food a person would need to consume to develop similar symptoms.
The small number of animals involved also means the experiment requires further testing and independent scientific assessment before its implications for human health can be established.
Researchers seek to identify substances affecting the brain
The research team is now seeking to determine the precise composition and concentration of the substances detected in the contaminated maize.
Echodu said the researchers were also examining mould contamination in sorghum after preliminary observations indicated that similar amino acids could be present in the cereal.
The investigation is intended to establish whether the substances identified in the grains have any neurological effects and, if so, how they might affect brain function.
Amino acids are the building blocks of proteins and are naturally present in food. Their detection in mould-contaminated maize does not, by itself, establish that they are toxic or responsible for the symptoms observed in the rats.
Researchers therefore need to identify the specific compounds, measure their concentrations and determine whether they can produce the observed effects under controlled conditions.
The team also wants to establish whether the suspected substances are present in food consumed by affected communities and whether exposure levels differ between households with and without people living with Nodding Syndrome.
Echodu said earlier investigations by his team had detected high levels of mycotoxins — toxic substances produced by certain fungi — in food consumed by households in northern Uganda.
He believes the latest investigation could provide another avenue for examining the possible role of contaminated food in the development of the disorder.
Earlier studies found no clear link with common mycotoxins
The new findings come against the background of previous scientific investigations into food contamination and Nodding Syndrome.
In 2018, Echodu and other researchers published a study in BMC Research Notes examining whether mycotoxin-contaminated food grains were associated with the condition in northern Uganda.
The researchers analysed cereal samples collected from households with and without children affected by Nodding Syndrome. They tested for aflatoxins, ochratoxin and deoxynivalenol, three types of mycotoxins associated with fungal contamination.
The study detected high levels of some toxins in food grains from both groups of households but found no significant association between the measured toxin concentrations and the presence of Nodding Syndrome.
The researchers concluded that their findings did not support a link between the measured mycotoxins in contaminated food and the condition.
A separate case-control study published in 2021 also detected foodborne mycotoxins in urine samples from people in Acholiland but found no significant difference in the presence of the detected substances between affected children and community controls.
These earlier findings do not necessarily rule out the new hypothesis because Echodu’s latest investigation is examining different substances and possible biological mechanisms.
However, they underline why the new observations must be tested more extensively before a causal relationship can be established.
Mass spectrometry equipment needed to advance research
Echodu said the research team faces a major equipment shortage that could delay efforts to establish conclusive evidence.
He said Gulu University needs a mass spectrometry machine estimated to cost more than Shs200 million to identify, quantify and profile the amino acids and proteins found in the contaminated food samples.
The laboratory’s existing equipment can detect the substances, but it cannot provide the detailed chemical analysis required to establish their exact composition and concentrations.
“We need a mass spectrometry machine to profile these proteins and amino acids. What we are doing currently is detecting them, but we need to quantify and analyze them in detail,” he said.
Mass spectrometry is an analytical technique used to identify chemical compounds and determine their quantities by measuring the mass-to-charge ratios of ions. It can help researchers establish which substances are present in a sample and how much of each compound it contains.
Echodu said access to the equipment would also strengthen investigations into the biological processes through which the substances might affect the brain.
The funding challenge comes as Uganda’s Ministry of Science, Technology and Innovation increases engagement with public universities to strengthen research and innovation.
Minister for Science, Technology and Innovation Eng. Jonard Asiimwe Akiiki visited Gulu University on November 6, 2026, as part of a programme assessing research facilities and the potential to translate scientific work into practical solutions.
The ministry has emphasised the need for research to produce measurable outcomes and address community challenges. However, a specific government funding commitment for the mass spectrometry equipment had not been established in the information available for this report.
Scientist urges households to discard mouldy maize
While the investigation continues, Echodu has urged households to improve the handling and processing of maize to reduce exposure to potentially harmful substances associated with mould contamination.
He warned that some families mix mouldy grains with healthy maize during food preparation, particularly when financial constraints make it difficult to discard part of their harvest.
“We encourage people to improve how they process their food. When you bring maize from the garden and start sorting it before processing, you need to remove those grains that are mouldy. But because household budgets are tight, people sometimes mix everything, and that gets into the food chain,” he said.
The advice is consistent with general food-safety guidance to remove visibly mouldy grains and prevent contaminated food from entering household supplies. Some fungal toxins can remain in food even after ordinary cooking, making prevention and proper storage important.
The scientist’s warning, however, should not be interpreted as evidence that eating mouldy maize causes Nodding Syndrome. The possible relationship remains under investigation.
What is Nodding Syndrome?
Nodding Syndrome is a neurological disorder and form of epilepsy characterised by repeated, involuntary dropping of the head, often accompanied by other seizures, cognitive impairment and developmental complications.
The condition mainly affects children, with most reported cases involving those between the ages of five and 15, although cases have been documented in a wider age range.
The syndrome was reported in northern Uganda in the early 2000s, with the Acholi sub-region experiencing a particularly severe burden. It has also been documented in South Sudan and Tanzania.
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Its defining head-nodding episodes are understood to be a type of seizure known as atonic seizures, which involve a sudden loss of muscle tone.
Scientific investigations have examined several possible risk factors, including infection with Onchocerca volvulus, nutritional deficiencies, food contamination and exposure to environmental toxins. However, no single cause has been conclusively established.
The US Centers for Disease Control and Prevention (CDC) has previously described the condition as an unexplained neurological disorder, noting that associations with onchocerciasis and malnutrition have been documented but remain inconclusive.
More than 4,000 children reportedly affected in Acholi
The scale of the condition in northern Uganda remains a major public health concern.
More than 4,000 children have reportedly been affected in the Acholi sub-region since the disease was first recognised in the area in the early 2000s.
The exact number of deaths associated with the syndrome remains unclear. However, information from the Archbishop John Baptist Odama Care Centre in Kitgum indicates that more than 500 recovering patients continue to require medical support.
The uncertainty surrounding its cause has complicated efforts to develop preventive measures and effective treatment for affected families.
For Echodu and his research team, the next phase will involve identifying the specific compounds detected in contaminated grains, establishing their concentrations and determining whether they can produce neurological effects through scientifically controlled investigations.
Until those questions are answered, the mouldy-maize hypothesis remains a research lead rather than an established explanation for Nodding Syndrome.
