Konzo and Ebola in Bandundu region of Zaire

Abstract

Outbreaks of konzo, an upper motor neuron disease, have been reported in rural African populations exposed to cyanide from eating cassava.1Tylleskär T Banea M Bikangi N Cooke R Poulter N Rosling H Cassava cyanogens and konzo, an upper motoneuron disease found in Africa.Lancet. 1992; 339: 208-211Summary PubMed Scopus (221) Google Scholar The prevalence of konzo is highest around Kikwit in the central Bandundu region of Zaire where bitter cassava roots that contain high concentrations of cyanogenic glucosides are the staple food. In the past, cassava was well soaked to remove cyanogens. However, in 1975, a new road from Kinshasa to Kikwit resulted in an intensive cassava trade during the dry season (May–September) that encouraged shortcuts to be taken in the soaking of cassava. Only insufficiently soaked cassava roots remained for household consumption, and poor families were consequently exposed to a high dietary intake of cyanide. After the promotion of safe processing, in 1990, there were no further outbreaks of konzo in Kikwit, though there was an outbreak around Popokabaka in western Bandundu in 1992. In November, 1992, the start of a health-education programme ensured that no further outbreaks occurred in the subsequent years. However, in 1995 and 1996, new cases were reported, and we set out in August to survey the catchment area of Masina health centre, one of many affected areas in Popokabaka health zone. Of 2723 inhabitants in 11 villages, 174 had gait disabilities and 69 met the diagnostic criteria for konzo.2WHOKonzo, a distinct type of upper motoneuron disease.Wkly Epidemiol Record. 1996; 71: 225-232PubMed Google Scholar A further 15 cases in individuals who had died were confirmed by information obtained from relatives and health staff; most had died from kwashiorkor. We interviewed 62 people with konzo and found that they had all eaten cassava daily in the months before disease onset. Some of the people we interviewed confirmed that before the outbreaks of konzo in the dry season, shortcuts were taken in the soaking of cassava because of increased sales, especially in 1992. The outbreak in 1995 was also preceded by such shortcuts, prompted by a sudden build-up of traders in Popokabaka after a military road block had been set up east of the road to Popokabaka; the road was blocked between May 12 and 23, because of an outbreak of Ebola in Kikwit.3WHOEbola haemorrhagic fever.Wkly Epidemiol Record. 1995; 70: 147-148PubMed Google Scholar Similarly, in 1996, there was intensive trading and shortcuts were taken in the soaking of cassava. We found that urine samples from 160 (75%) of 213 randomly selected villagers from the catchment area had urinary thiocyanate concentrations of 300 μmol/L or more, indicating increased high exposure to cyanide. Our findings suggest that intensive trading, shortcuts in the soaking of cassava, and subsequent exposure to cyanide have a causative role in konzo. We believe that the promotion of safe processing can prevent the disease.4Banea M, Tylleskär T, Gitebo N, et al. Geographical and seasonal association between linamarin and cyanide exposure from cassava and the upper motoneuron disease konzo in Zaire. Trop Med Int Health (in press).Google Scholar The recurrence of konzo in Popokabaka may reflect an increase in trading close to Kinshasa because of poor road maintenance in Zaire, but the temporal relation of the outbreak and the statements from the population suggest that the road block also contributed to this recurrence. This link between the road block and the outbreak of konzo constitutes an additional risk of such military action. We question whether such military action against impoverished people threatened by epidemics is at all effective. Medical advisers should defend the basic human rights of these people. Because securing essential medical care, preventive services, and food security can stop diseases such as Ebola,3WHOEbola haemorrhagic fever.Wkly Epidemiol Record. 1995; 70: 147-148PubMed Google Scholar trypanosomiasis,5Ekwanzala M Pépin J Khonde N Molisho S Bruneel H De Wals P In the heart of darkness: sleeping sickness in Zaire.Lancet. 1996; 348: 1427-1430Summary Full Text Full Text PDF PubMed Scopus (67) Google Scholar and konzo,1Tylleskär T Banea M Bikangi N Cooke R Poulter N Rosling H Cassava cyanogens and konzo, an upper motoneuron disease found in Africa.Lancet. 1992; 339: 208-211Summary PubMed Scopus (221) Google Scholar which are all increasing because of the social collapse in Bandundu, the poorest region in Zaire.