Recurrence of konzo in southern Tanzania: Rehabilitation and prevention using the wetting method

Mlingi, N.; Nkya, Siana; Tatala, Simon; Rashid, Seif; Bradbury, J. H.

doi:10.1016/j.fct.2010.09.017

Cited by 38 publications

(59 citation statements)

References 18 publications

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“…These illnesses include tropical ataxic neuropathy, epidemic spastic paraparesis, also known as konzo (Cliff, Muquingue, Nhassico, Nzwalo, & Bradbury, 2011;Rosling, 1988). These problems have been reported in the Democratic Republic of Congo, Nigeria, Tanzania and Mozambique (Ciglenecki et al, 2011;Mlingi, Nkya, Tatala, Rashid, & Bradbury, 2011;Nhassico, Muquingue, Cliff, Cumbana, & Bradbury, 2008).…”

Section: Introductionmentioning

confidence: 99%

Straightforward rapid spectrophotometric quantification of total cyanogenic glycosides in fresh and processed cassava products

Tivana¹,

Francisco²,

Zelder³

et al. 2014

Food Chemistry

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In this study, we extend pioneering studies and demonstrate straightforward applicability of the corrin-based chemosensor, aquacyanocobyrinic acid (ACCA), for the instantaneous detection and rapid quantification of endogenous cyanide in fresh and processed cassava roots. Hydrolytically liberated endogenous cyanide from cyanogenic glycosides (CNp) reacts with ACCA to form dicyanocobyrinic acid (DCCA), accompanied by a change of colour from orange to violet. The method was successfully tested on various cassava samples containing between 6 and 200 mg equiv. HCN/kg as verified with isonicotinate/1,3-dimethylbarbiturate as an independent method. The affinity of ACCA sensor to cyanide is high, coordination occurs fast and the colorimetric response can therefore be instantaneously monitored with spectrophotometric methods. Direct applications of the sensor without need of extensive and laborious extraction processes are demonstrated in water-extracted samples, in acid-extracted samples, and directly on juice drops. ACCA showed high precision with a standard deviation (STDV) between 0.03 and 0.06 and high accuracy (93-96%). Overall, the ACCA procedure is straightforward, safe and easily performed. In a proof-of-concept study, rapid screening of ten samples within 20 min has been tested. a b s t r a c tIn this study, we extend pioneering studies and demonstrate straightforward applicability of the corrinbased chemosensor, aquacyanocobyrinic acid (ACCA), for the instantaneous detection and rapid quantification of endogenous cyanide in fresh and processed cassava roots. Hydrolytically liberated endogenous cyanide from cyanogenic glycosides (CNp) reacts with ACCA to form dicyanocobyrinic acid (DCCA), accompanied by a change of colour from orange to violet. The method was successfully tested on various cassava samples containing between 6 and 200 mg equiv. HCN/kg as verified with isonicotinate/1,3-dimethylbarbiturate as an independent method. The affinity of ACCA sensor to cyanide is high, coordination occurs fast and the colorimetric response can therefore be instantaneously monitored with spectrophotometric methods. Direct applications of the sensor without need of extensive and laborious extraction processes are demonstrated in water-extracted samples, in acid-extracted samples, and directly on juice drops. ACCA showed high precision with a standard deviation (STDV) between 0.03 and 0.06 and high accuracy (93-96%). Overall, the ACCA procedure is straightforward, safe and easily performed. In a proof-of-concept study, rapid screening of ten samples within 20 min has been tested.

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Section: Introductionmentioning

confidence: 99%

Straightforward rapid spectrophotometric quantification of total cyanogenic glycosides in fresh and processed cassava products

Tivana¹,

Francisco²,

Zelder³

et al. 2014

Food Chemistry

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“…Konzo epidemics of the past century, from the late 1920s to late 1940s (Trolli, 1939;Vileu, 1942;Lucasse, 1952) and from the late 1970s to present time (World Health Organisation, 1982;Ministry of Health Mozambique, 1984;Howlett et al, 1992;Mlingi et al, 2011) occurred during warm climate regimes (Figure 1). Anomalies of the north Pacific Ocean surface temperature and pressure (PDO), which modulate global climate, persist in the same mode for two to three decades before shifting to another mode.…”

Section: Discussionmentioning

confidence: 99%

“…Studies of the strengths of El Niños (Quinn and Neal, 1987;Wolter and Timlin, 1998) have shown that high amplitude El Niños occurred in 1932, 1940-1941, 1982-1983, 1986-1987, and 1997-1998. All these strong El Niños were followed by konzo epidemics (Trolli, 1939;Vileu, 1942;Ministry of Health Mozambique, 1984;Howlett et al, 1990Howlett et al, , 1992Mlingi et al, 2011), Figure 1. High amplitude El Niños are associated with severe droughts and food shortages.…”

Section: Discussionmentioning

confidence: 99%

“…Years of occurrence of all konzo epidemics in the past century in DR Congo (Trolli, 1939;Vileu, 1942;Lucasse, 1952;World Health Organisation, 1982;Tylleskar et al, 1991;Bonmarin et al, 2002;Chabwine et al, 2011), Mozambique (Ministry of Health Mozambique, 1984Cliff, 1994;Ernesto et al, 2002;Cliff et al, 2011), Tanzania (Howlett et al, 1990(Howlett et al, , 1992Mlingi et al, 2011), and Central African Republic (Ciglenecki et al, 2011) were obtained from published studies. Cycle plots of ENSO and PDO timeseries from 1915 to 2014 were drawn to show the warm and cold phases.…”

Section: Konzo Epidemics Datamentioning

confidence: 99%

“…Disabling spastic paraparesis is the residual deficit in most subjects (Ministry of Health Mozambique, 1984). Major konzo epidemics occurred during severe droughts from the late 1920s to late 1940s (Trolli, 1939;Vileu, 1942;Lucasse, 1952), and from the late 1970s to early 2000s (World Health Organisation, 1982;Ministry of Health Mozambique, 1984;Tylleskar et al, 1991;Ciglenecki et al, 2011;Mlingi et al, 2011). Interannual konzo cases occurred, however, between epidemics (Tylleskar et al, 1991;Cliff, 1994).…”

Section: Introductionmentioning

confidence: 99%

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Climate regimes, El NiÃ±o-Southern oscillation and konzo epidemics

Oluwole

2015

Front. Environ. Sci.

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Epidemics of konzo have occurred during severe droughts in parts of east, central, and southern Africa since the 1920s. Occurrence is attributed to exposure to cyanide from poorly processed cassava foods, the sole source of calories when other food crops fail. El Niño, the warm phase of the El Niño-Southern Oscillation (ENSO), induces severe droughts in the geographical areas of Africa where epidemics of konzo occur. Climate regimes are determined by modes of Pacific Decadal Oscillation (PDO), which modulates the ENSO. Study was done to determine the relationship of konzo epidemics to climate regimes and phases of ENSO, and to propose a model to explain while konzo epidemics do not occur in all drought affected areas. Data of all konzo epidemics in the past century and in DR Congo from 1974 to 1996, and indices of ENSO and PDO from 1915 to 2014 were obtained. Konzo epidemics were mapped to phases of ENSO and PDO. Wavelet spectral and wavelet spectral coherence analysis of climate indices and konzo epidemics were done. All konzo epidemics of the past century occurred during warm climate regimes. Of 19 warm phases of ENSO from 1974 to 1996 in DR Congo, 17 were coupled to konzo epidemics, while of 4 cold phases of ENSO, 1 was coupled to konzo epidemic, odds ratio 26 (95% CI, 2-378). Global spectral of ENSO and konzo showed dominant periodicity of 5 years, while spectrograms showed significant periodicities and coherence between 3 and 6 years. Spatial distribution of konzo is restricted to the area of maximal impact of El Niño on precipitation in Africa. El Niño is the underlying cause of konzo epidemics. Control of konzo epidemics requires management of the impact of El Niño on agriculture in areas where the population depends on cassava as sole source of calories during droughts. There is the need to develop forecast models of changes in cassava production to predict likely periods of konzo epidemics.

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