Abstract

There were 68 konzo cases in three villages in Boko Health Zone, Bandundu Province, Democratic Republic of Congo (DRC), where yearly incidence had increased greatly since 2009. The nine months long intervention to prevent konzo started in the wet season. Village women were taught the wetting method, after which there were no new konzo cases and urinary thiocyanate levels were low. Using data from four different interventions in March 2010, July 2011, September 2013 and the present intervention in October-November 2012, a correlation was found between the monthly cyanide intake (measured by percentage of children with high urinary thiocyanate level) and the monthly konzo incidence. This dose response relationship between cyanide intake and konzo incidence, together with the prevention of konzo in many villages using the wetting method to reduce cyanogen intake, shows that konzo is very likely to be due to high cyanide/low sulfur amino acid intake in a diet of bitter cassava.

Key words: Dose-response relation, konzo prevalence, urinary thiocyanate, cyanide, cassava flour, wetting method.