Working together to eliminate , konzo and tropical ataxic neuropathy (TAN).

Cassava Cyanide Diseases Network

Issue number 1, June 2003

Contents Cyanide and Thiocyanate Kits

Cyanide and thiocyanate kits...1 The total cyanide content of developing countries. The kits roots and flour may be are funded by the Australian Konzo Count……………………1 determined using a simple Centre for International picrate kit developed by Dr Agricultural Research (ACIAR) Cyanide poisoning…………… 2 Bradbury and coworkers at the and may also be purchased by Australian National University in workers in developed countries. Strategy to eliminate konzo …..2 1996. The kit contains all that is Nearly 250 kits have been needed to analyse 100 samples supplied to workers in 35 Impact of environmental factors of root or flour. A stepwise countries. on cyanide content in cassava 2 procedure (protocol) must be Kit A (cassava roots), Kit B2 followed, which is available in (cassava products-flour,gari etc), Konzo ………………………….3 English, French, Portuguese and Kit D1 (urinary thiocyanate) and Bahasa Indonesia. Kit E (cyanogenic leaves) are In the human body much of the available. ingested cyanide is converted to The kits have been used to thiocyanate which is removed in screen cassava collections and the urine. The urinary remove those of high cyanide thiocyanate content gives a content, to show the effect of measure of the recent cyanide drought on cyanide levels and to intake. In 1998 a simple picrate give warning of outbreaks of kit method with 100 analyses konzo, to check out cassava CCDN Coordinator: was developed for urinary leaves and roots for animal use Dr. J. Howard Bradbury thiocyanate. and to measure urinary School of Botany and Zoology These kits are available from Dr thiocyanate levels in children Australian National University Bradbury free of charge to health exposed to cyanide from Canberra ACT 0200, Australia and agricultural workers in cassava flour. Phone: +61-2-6125 0775 E-mail: [email protected] Coordinating Group: Konzo Count Julie Cliff, Paula Cardoso, Mario Ernesto (); Rezaul There are published reports of Mozambique and of its Haque (Australia) konzo occurring in Mozambique, occurrrence in three locations in Country Contacts: Tanzania, the D.R.Congo, Tanzania. D.R. Congo: D.D. Ngudi, India: Cameroon, Central African Bala Nambisan and K.T. Shenoy, We appeal to our readers to let Republic and anecdotal reports us know whether konzo Indonesia:A.Hidayat,Mozambique of konzo from Angola and :Anabela Zacarias. occurs at all in your region. If Website: Uganda. Currently, there are it is present could you, if www..anu.edu.au/BoZo/CCDN reports of 620 cases of konzo in possible, inform us of the Bandundu region of D.R.Congo, approximate number of cases. about 300 in Northern Cyanide Poisoning Strategy to Eliminate genetically controlled, but Konzo environmental and cultural conditions also influence its Consumption of cassava roots or level. Shade conditions increase cassava products (such as At a Workshop in Nampula, in the cyanogens content in the cassava flour, gari and fufu) that November 2000 a strategy was tuber, because of the metabolic contain large amounts of developed for the elimination of changes induced by low rates of cyanide compounds may cause konzo in Mozambique. This photosynthesis. Drought acute intoxication within 1-4 strategy should be applicable in conditions also increase the hour. Symptoms include all countries in which konzo tuber cyanogen content, vomiting, nausea, dizziness, occurs. The four points which presumably due to increased palpitation, weakness, stomach make up the strategy are given translocation of pains, headache and diarrhoea, below. For a more detailed linamarin/metabolites to the which all cleared within 24 account see Roots1. 1,2 tuber, as a result of leaf hourst . In some cases cyanide 1. Introduce other staples, senescence. Irrigation, on the poisoning causing death has vegetables, pulses and fruits to other hand, facilitates starch occurred after consumption of decrease the daily cyanide accumulation in the tuber, cassava roots or products such intake and broaden the diet of 1 prevents leaf senescence and as gari . the people. decreases the cyanogen content Cyanide inactivates the enzyme 2. Improve processing of in the tuber; a 40% decrease in cytochrome oxidase which cassava roots to produce flour cyanogens content is observed, catalyses one of the reactions that has less residual cyanide. as compared to non-irrigated. involved in respiration For example, in Mozambique the Application of nitrogen causes (oxidation of food). Respiration is heap fermentation method marginal increase in linamarin therefore stopped, key energy produces flour with about one content, due to higher free conversion processes are halted half the cyanide content of flour amino acid levels while and heart failure occurs rapidly. processed by sun drying. application of potassium Sodium thiosulphate or nitrites 3. Introduction of low cyanide, increases tuber starch and are effective antidotes for high yielding, well-adapted, lowers the cyanogen content. A cyanide poisoning. disease-resistant varieties of significant decrease in tuber In correspondence with many cassava, facilitated by IITA. and cyanogen is achieved by pruning workers in cassava–growing other Centres. or girdling the stem one or two countries, I have received 14 4. Improve early warning months before the tubers are reports of cases of acute systems. Warning of a possible harvested.Both these techniques intoxication and sometimes konzo epidemic may be obtained arrest the translocation of deaths. These reports are very by using picrate kits to monitor linamarin from leaves to tubers widespread from Zambia, cyanide levels in cassava roots and also induce increased Ghana, Nigeria, D.R.Congo, and cassava products and degradation of linamarin in Cameroon, Tanzania, Benin, amounts of urinary thiocyanate tubers. The cyanogen in tubers Malaysia, Cote D’Ivoire and in the population. is reduced by 40–50 % by these Ethiopia. processes. However, the tubers Since this problem results from Reference 1 Ernesto, Cardoso, Nicala, Mirione, also show decreased dry the cyanide toxicity of both matter/starch, (ca 5% decrease) cassava roots and processed Massaza, Cliff, Haque & Bradbury, Roots (Newsletter of SARRNET and which makes them unacceptable cassava it will not be solved, by EARRNET), 8, No 1, Dec. 2002, for cooking, but suitable for improvements in processing 8-11. preparation of drychips/ flour, methods. It can be eliminated which is the raw material for a altogether, as in the South Impact of Environmental number of food products. Pacific (PNG, Fiji etc), by using Thus high cyanogen sweet, low cyanide cassava Factors on Cyanide Content in Cassava potential tubers can be varieties. Broadening the diet of converted into lower cyanogen the people would also be potential tubers by manipulation beneficial. Cassava varieties show a large of cultural conditions. The References contribution of field cultural 1Akintonwa, Tunwashe & Onifade, variation in the cyanoglucoside Acta Hort. 375, 285-288, (1994). (linamarin) content of the edible practices in modulating tuber 2 Mlingi, Poulter & Rosling, Nutr. tuber, ranging from 15 to 450µg cyanogens level needs to be Res. 12, 677-687, (1992). cyanide equivalent/g fresh addressed. tissue. The concentration of References J. Howard Bradbury. cyanogen in the tuber is Ramanujam & Indira, Ind.J.Plant Physiol. 27, 355-360, (1985). 2 CCDN News Nambisan, (1996) Does transport of The first described cases of another compound. linamarin occur in cassava? In: konzo occurred in 1928, in the Konzo patients also have a diet Tropical tuber crops - Problems, then Belgian Congo (now D.R. that is very low in sulphur prospects and future strategies Congo). containing amino acids and (Kurup et al. Eds) p 21-26. Where does konzo occur sulphur amino acid deficiency Bala Nambisan. now? may be necessary for konzo to Konzo has been described in the occur. Konzo , D.R. The underlying cause of konzo is Congo,Cameroon, Mozambique, poverty, which forces people to What is konzo? and Tanzania. There are also subsist on a diet of insufficiently- Konzo is a disease anecdotal reports of konzo from processed bitter cassava. The characterized by the sudden Angola and Uganda. emergence of konzo in the past onset of of both legs. Who is affected by konzo? thirty years in many countries of The paralysis is called spastic Konzo affects mostly children of Africa reflects the increasing because the affected legs are both sexes above the age of two rural poverty of the continent. rigid, not floppy (as in a flaccid years and women of child- What is the treatment for paralysis), and the reflexes are bearing age. Adult men are also konzo? increased. Konzo patients walk affected, but not as often. There is no specific treatment. with a typical spastic gait. When does konzo occur? Konzo patients respond well to The paralysis is of varying Konzo occurs at times of physiotherapy. Even patients degrees of severity – in the most extreme agricultural crisis, for who cannot walk may be able to severe cases, the patient cannot example during drought and war. walk with physiotherapy and walk at all. In moderate cases, It usually shows a seasonal walking aids. Patients and carers the patient needs support (one distribution, coinciding with the should also be taught how to or two sticks or crutches). In mild dry season. In Mozambique, this prevent contractures. cases, the patient can walk is also the time of the cassava How can konzo be eliminated? without support, but still has the harvest. In times of crisis, it often The key to konzo elimination lies typical walk. appears in epidemics, with large in rural development. The Konzo patients may also have numbers of cases. However, poorest rural cassava-dependent weakness of the arms, difficulty konzo also occurs in less communities should be targets in talking, seeing and hearing. extreme circumstances in the for development assistance. The damage to the nervous poorest rural cassava-dependent Specifically, they need support system caused by konzo is communities of Africa, when to vary their diet and the crops permanent. It neither gets better cases may be sporadic. they grow. Breeding and nor worse, although patients What causes konzo? distribution of improved sweet may have further attacks, which Bitter cassava contains high cassava varieties is an option worsen their condition. They concentrations of cyanogenic when farmers desire them. This may also get functional glucosides (mostly linamarin), is not the easy solution it might improvement with physiotherapy, which are broken down to appear, as farmers may have or as they adapt to their release cyanide. Around the time chosen bitter cassava because condition. Also, if patients are of onset, konzo patients always of its drought- and theft-resistant not treated with physiotherapy, have cyanide poisoning. High properties. Improved cassava they may develop permanent concentrations of thiocyanate processing is another option. contractures – shrinkage and (the main product of cyanide Once again, it may not be an shortening of the muscles. metabolism in the body) are easy solution, as improved How is konzo different from found in blood and urine. methods may be more labour- other diseases that cause To make it safe for eating, bitter intensive and time-consuming. spastic paralysis? cassava needs processing to Building on local knowledge may Most other causes of spastic lower the cyanide levels. Konzo help, for example in paralysis do not begin suddenly is often associated with short- Mozambique we have found that and then stay stationary, as cuts in processing. For example, women use the more efficient konzo does. in areas where processing is by heap fermentation process in The main distinguishing feature sun-drying, people cannot wait preference to sun-drying at of konzo is that it has always to complete the process if they times of greater risk of konzo. been reported in association with are hungry. Finally, we need improved early a monotonous diet of bitter We do not know for certain what warning systems in konzo areas, cassava. directly causes konzo – cyanide, so that epidemics are detected When and where did konzo one of its metabolic products, and prevented well in advance. first occur? linamarin, or maybe even Julie Cliff CCDN News 3 CCDN News is the Newsletter of the Cassava Cyanide Diseases Network (CCDN). The CCDN is a free, worldwide network commenced in June 2001, which is working towards the elimination of konzo, TAN and other cassava cyanide diseases.

CCDN News will consider for publication short articles and letters (1-2 pages A 4 double spaced) written in English concerned with the following subjects: 1. Cyanide poisoning, konzo, TAN, goitre and cretinism facilitated by cyanide intake from cassava and any other cyanide diseases due to cassava. 2. Reduction of cyanide intake from cassava through agricultural and nutritional means such as by broadening the diet of cassava consumers through introduction of new crops, pulses, vegetables and fruits, and by reducing the cyanide content of cassava varieties through selection and breeding. The effect of environmental factors such as drought on cyanide levels in cassava. 3. Processing methods for conversion of cassava roots to stable food products of low cyanide content. 4. Chemical analysis to determine the total cyanide content in cassava roots and products and thiocyanate in urine. 5. Other relevant matters of interest. Because CCDN News is a newsletter, full-size original papers or reviews cannot be considered for publication.

Material published in CCDN News may be freely reproduced, but please always indicate that it comes from CCDN News. We wish to thank Miss Belinda Purdey for designing and setting up the front page. Please send all correspondence to the CCDN Coordinator, Dr J Howard Bradbury, see p. 1 for address.

4 CCDN News