Study Shows Konzo's Affect on Cognitive Function, Disease Associated with War and Drought

Konzo, a disease known to often come with war and drought, goes beyond many devastating physical effects and harm a child's memory, problem solving and cognitive abilities. Even children without the physical symptoms associated with the disease often lose the ability to function cognitively when exposed to the toxin that causes the rare disease, according to researchers, with reports from the journal Pediatrics.

"That's what's especially alarming," said lead author Michael Boivin, a Michigan State University associate professor of psychiatry and of neurology and ophthalmology. "We found subtle effects that haven't been picked up before. These kids aren't out of the woods, even if they don't have the disease."

Konzo, which means "bound legs" in the African Yaka language, s an epidemic paralytic disease first described by G. Trolli in 1938, who discovered it amongst the Kwango of the Belgian Congo. The outbreaks are associated with several weeks of almost exclusive consumption of insufficiently processed "bitter" (cyanide-rich) cassava as a famine food. In northern Mozambique the disease is known as mantakassa, according to PLOS Neglected Tropical Diseases.

People contract konzo by consuming poorly processed bitter cassava, a drought-resistant staple food in much of sub-Saharan Africa. Typically, the plant's tuber is soaked for a few days, then dried in the sun and ground into flour - a process that degrades naturally occurring cyanide, according to a press release.

"As long as they do that, the food's pretty safe," said Boivin, who began studying konzo in 1990 as a Fulbright researcher in the Democratic Republic of Congo. "But in times of war, famine, displacement and hardship, people take shortcuts. If they're subsisting on poorly processed cassava and they don't have other sources of protein, it can cause permanent damage to the nervous system.

"Konzo doesn't make many headlines because it usually follows other geopolitical aspects of human suffering," he added. "Still, there are potentially tens of millions of kids at risk throughout central and western Africa. The public health scope is huge."

To find out if the disease affects cognitive function, Boivin and colleagues from Oregon Health and Science University turned to the war-torn Congo. They randomly selected 123 children with konzo and 87 neighboring children who showed no signs of the disease but whose blood and urine samples indicated elevated levels of the toxin.

Using cognitive tests, the researchers found that children with konzo had a much harder time using working memory to solve problems and organize visual and spatial information.

They also found that konzo and non-konzo children from the outbreak area showed poor working memory and impaired fine-motor skills when compared to a reference group of children from a part of the region unaffected by the disease.