Konzo prevention in six villages in the DRC and the dependence of konzo prevalence on cyanide intake and malnutrition.

Six villages in Boko Health Zone, Bandundu Province, DRC, were studied with 4588 people, 144 konzo cases and konzo prevalences of 2.0-5.2%. Konzo incidence is increasing rapidly in this area. Food consumption scores were obtained from the households with konzo and the mean % malnutrition calculated for each village. Urine samples were obtained from 50 school children from each village and % high urinary thiocyanate content (>350 µmol/L) determined. The experimental data relating % konzo prevalence (%K) to % children with high urinary thiocyanate content (%T) and % malnutrition (%M) for the six villages were fitted to an equation %K = 0.06%T + 0.035%M. This confirms that konzo is due to a combination of high cyanide intake and malnutrition. The village women used the wetting method to remove cyanogens from cassava flour. During the 9-month intervention there were no new cases of konzo; cyanide in flour had reduced to WHO safe levels and mean urinary thiocyanate levels were greatly reduced. To prevent konzo at least 60-70% of women should use the wetting method regularly. The wetting method is now accepted by the World Bank, FAO and WHO as a sensitive intervention. Four successful konzo interventions have involved nearly 10,000 people in 13 villages, the cost is now $16 per person and the methodology is well established.

Effectiveness of wetting method for control of konzo and reduction of cyanide poisoning by removal of cyanogens from cassava flour.

BACKGROUND: Konzo is an irreversible paralysis of the legs that occurs mainly among children and young women in remote villages in tropical Africa and is associated with a monotonous diet of bitter cassava. Konzo was discovered in 1938 by Dr. G. Trolli in the Democratic Republic of Congo (DRC). It also occurs in Mozambique, Tanzania, Cameroon, Central African Republic, and Angola. It was first controlled in Kay Kalenge village, DRC, in 2011 with the use of a wetting method to remove cyanogens from cassava flour. Fourteen months later, another visit was made to Kay Kalenge. OBJECTIVE: To determine whether Kay Kalenge women were still using the wetting method, whether there were new cases of konzo, and whether the wetting method had spread to other villages. METHODS: Meetings were held with chiefs, leaders, and heads of mothers' groups, women from 30 households were interviewed, and three nearby villages were visited. Total cyanide and thiocyanate were analyzed in cassava flour and urine samples, respectively. RESULTS: The women in Kay Kalenge village still used the wetting method. There were no new cases of konzo. The mean cyanide content of the flour samples was 9 ppm, and no child had a mean urinary thiocyanate content greater than 350 micromol/L. The use of the wetting method had spread naturally to three adjacent villages. CONCLUSIONS: The wetting method has been readily accepted by rural women as a simple and useful method to control konzo by removing cyanide from cassava flour, and its use has spread to nearby villages. The wetting method should be promoted by health authorities to control konzo and reduce cyanide poisoning from high-cyanide cassava flour.

Control of konzo by detoxification of cassava flour in three villages in the Democratic Republic of Congo.

Three villages in Boko Health Zone, Bandundu Province, Democratic Republic of Congo (DRC), had 61 konzo cases and konzo prevalences of 2.5%, 4.1% and 7.5% respectively. Konzo cases occurred every year for 10 years and every month, peaking in July. The high mean cyanide content of cassava flour of 50 ppm was due to short soaking of cassava roots for 1-2 days instead of 3-4 days. Konzo cases were examined and village women taught the wetting method that removes cyanogens from flour. The villages were visited every month for 1 year following previous methodology. No new konzo cases occurred during the intervention, mean flour cyanide levels reduced from 50 to 14 ppm and mean urinary thiocyanate levels of school children reduced from 930 to 150 µmole/L. The percentage of children with urinary thiocyanate levels of >350 µmole/L was reduced from a maximum of 80 in Ikialala before the intervention to 0 in Ikusama, Ikialala and 3 in Imboso Mwanga 1 year later. This is the second time that konzo has been controlled and success depends on regular use of the wetting method by village women. The methodology is now being used in other villages in DRC with financial support of AusAID.

Control of konzo in DRC using the wetting method on cassava flour.

Fifty konzo cases were identified in four villages in Popokabaka Health Zone, DRC. One third of people had only one meal per day, mainly of cassava flour consumed as a thick porridge (fufu) and pounded, boiled cassava leaves. Retention of cyanogens in flour resulted from short soaking of cassava roots. A 1.5 years intervention was made in the largest village Kay Kalenge, where the wetting method was taught to all women of the village, who accepted it willingly. The total cyanide content of cassava flour was reduced to below 10 ppm. Fufu from treated flour tasted and stored better than fufu from untreated flour. The mean urinary thiocyanate content of 100 school children reduced from 332 to 130 µmole/L and the number of samples exceeding 350 µmole/L decreased from 26 to 0 during the intervention. No new konzo cases occurred, which included two dry seasons when konzo peaks. Konzo was first identified by Dr. Trolli in 1938 in Popokabaka Health Zone and it has now been prevented for the first time in the same area. The methodology is now in use in Boko Health Zone and we believe it is the most effective way to control konzo in tropical Africa.