The public has been cautioned to be vigilant when buying fresh cassava tubers from markets to avoid buying inedible varieties.
Faustin Machara, a nutritionist at Rwanda Biomedical Centre, said cooking of cassava tubers makes them consumable but absorption of poorly cooked cassava can result into poisoning.
He made the remarks while commenting on last week's incident when three children died after eating inedible cassava in Musanze District.
"Cassava is an inexpensive source of carbohydrates, but its consumption without proper preparation can create health problems. Cassava (bitter variety) contains toxic cyanogenic glycosides which, under the effect of an enzyme, are transformed into hydrocyanic acid," Machara told The New Times.
Three children died last week after consuming poisonous cassava, locally known as Gitamisi in Muko Sector, Musanze District.
Their father, Phocas Bazibukaryari, 35, survived narrowly.
The siblings, including a girl, were aged 5, 7 and 10, all studying at Kamugonga Primary School.
The children ate cassava not meant to be eaten in its fresh form yet its meant to be used to make cassava bread only after fermenting, according to health workers and nutritionists.
Aloysie Niyibizi, the executive secretary of Muko Sector, explained that the father of the deceased kids had bought the cassava from a local market and cooked it while the wife was away.
But the children and their father fell ill immediately after eating the cassava.
"Neighbours took the affected people to a local health centre, but upon reaching they were referred to Ruhengeri Hospital. The father was treated but children died on the way to hospital," he said.
Niyibizi blamed the trader who sold inedible stuff to the victims.
Jean de Dieu Muhire, the in charge of public relations at Ruhengeri Hospital, said the children were pronounced dead on reaching the hospital while their father was admitted in critical condition.
Machara, the nutritionist, explained that the consumed cassava contains cyanide acid that is harmful to human health when consumed fresh.
Speaking from hospital, Bazibukaryari narrated that he couldn't distinguish cassava types on the market.
My child who had travelled with the mother is the only one who survived, he lamented.
Machara explained that after eating the poisonous cassava tubers, symptoms of poisoning by cyanide manifest four to six hours after a meal.
They include dizziness, vomiting, malaise, hypotension, convulsions, respiratory arrest, in some cases leading to death within an hour or two.
The lethal dose is estimated to be 0.5 / 1 mg of hydrocyanic acid per kilogramme of body weight, he said.
However, cassava poisoning can cause other chronic diseases such as neurological manifestations, endemic goitre, and tropical pancreatitis, he added.
Traditional processing methods, such as fermentation, drying and cooking, if applied with care, can also reduce the cyanide content to non-toxic levels. The released cyanide dissolves in the water during fermentation and evaporates when the fermented cassava is dried.