Appearance of konzo in South-Kivu, a wartorn area in the Democratic Republic of Congo

• Published in: Food and chemical toxicology 2011-03, Vol.49 (3), p.644-649
• Main Authors: Chabwine, J.N., Masheka, C., Balol’ebwami, Z., Maheshe, B., Balegamire, S., Rutega, B., wa Lola, M., Mutendela, K., Bonnet, M.-J., Shangalume, O., Balegamire, J.M., Nemery, B.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Burhinyi; Cassava; Child; Child, Preschool; Cyanides - poisoning; cyanogen; Cyanogens; Democratic Republic of the Congo - epidemiology; Female; food shortages; Foodborne Diseases - complications; Foodborne Diseases - epidemiology; harvest date; Humans; Konzo; malnutrition; Malnutrition - complications; Manihot - chemistry; Manihot - poisoning; Manihot esculenta; Motor Neuron Disease - epidemiology; Motor Neuron Disease - etiology; neurons; new variety; Nitriles - analysis; Paraparesis, Spastic - complications; Paraparesis, Spastic - epidemiology; people; Plant Roots - chemistry; Plant Roots - poisoning; roots; Spastic paraparesis; surveys; Thiocyanates - urine; Toxicity; toxicology; Young Adult
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2010.07.050

Konzo is an upper motor neuron disease characterized by sudden-onset and irreversible spastic paraparesis occurring in nutritionally compromised people. It is associated with consumption of insufficiently processed cyanogenic-toxic cassava. Cassava, the main caloric source in the Democratic Republic of Congo, has been safely consumed for decades in the Eastern Province of South-Kivu. However, in the context of long-lasting war and violent conflicts, cases of spastic paraparesis resembling konzo appeared in a populous area (Burhinyi). Two field surveys (2003 and 2005) identified 41 subjects meeting clinical criteria of konzo and suffering from (chronic) malnutrition. Their urinary thiocyanate concentrations (median 129, range 20–688, SD 146 μg/L), and cyanogen levels (median 20 ppm, range 5–300 ppm, SD 73 ppm) in cassava roots from their household stocks were high. The source of cyanogenic-toxicity was unprocessed fresh cassava roots during harvest period, but probably also insufficiently processed roots. This first report of konzo in South-Kivu concludes that occurrence of konzo was triggered by food shortages because of the longstanding state of insecurity. Contributory factors included the introduction of new varieties of (bitter) cassava, but konzo may actually be caused by a combination of factors that are yet to be understood.