Lathyrism and Socioeconomic Disparities: A Neglected Public Health Problem in Northeast Ethiopia.

Lathyrism is an incurable neurological disorder, resulting from excessive consumption of grass pea (Lathyrus sativus), which clinically manifests as paralysis of lower limbs. Because of the high production of grass peas, a large number of people are expected to be affected by the disease in Northeast Ethiopia. However, there is no comprehensive study that quantified the magnitude of the problem. Therefore, in this study, we determined the prevalence of lathyrism and socioeconomic disparities in Northeast Ethiopia. A community-based cross-sectional study was used which used a quantitative method of data collection from January to February 2019. Data were collected from a total of 2,307 inhabitants in the study area using structured questionnaires. Lathyrism cases were identified using a case definition of symmetrical spastic leg weakness, and subacute or insidious onset, with no sensory deficit, and with a history of grass pea consumption before and at the onset of paralysis. The majority (56.8%) of participants were male, and 34.7% were aged 45 years or older. Overall, the prevalence of lathyrism was 5.5%, and it was higher in males (7.9%) than in females (2.5%). Moreover, the prevalence was higher among farmers (7.0%) than merchants (0.3%), very poor economic status (7.2%) than very rich (1.1%), who produced (9.6%) grass pea than not produced (0.9%), and those who used clay pottery (6.2%) than metal (4.8%) for cooking. The prevalence of lathyrism in Northeast Ethiopia is remarkably high. Therefore, we recommend lathyrism to be among the list of reportable health problems and incorporated in the national routine surveillance system.

Neurolathyrism in goat (Capra hircus) kid: Model development.

The present study was undertaken to develop an animal model to study neurolathyrism. For this purpose 24 goat (Capra hircus) kids (new born, 15 days old) were divided into four groups. Group I Control, Group II Low toxin (0.17 g% ß-ODAP containing grass pea), Group III high toxin (0.96 g% ß-ODAP containing grass pea) and Group IV high toxin (0.96 g% ß-ODAP containing grass pea flour (powder) fortified with 5 mg% pure ß-ODAP). The experiment was continued for 3 months. Clinical examination was carried out weekly. Muscle conduction velocity (MCV), nerve conduction velocity (NCV), blood and urinary ß-ODAP, nitrite in blood and cerebrospinal fluid (CSF) examination were performed by standard methods. Clinical examination showed neurolathyrism symptoms in three kids. The abnormal MCV and NCV were observed in all the experimental animals. Blood nitrite, blood and urine ß-ODAP levels were significantly increased in experimental groups. Three kids were affected with neurolathyrism due to consumption of grass pea irrespective of its ß-ODAP content and kid may serve as a neurolathyrism model.

Historical setting and neuropathology of lathyrism: Insights from the neglected 1944 report by Oliveras de la Riva.

Lathyrism is a central motor system disorder recognized since antiquity resulting from prolonged dietary dependence on the grasspea (Lathyrus sativus). The neuropathology underlying the characteristic spastic paraparesis of lathyrism is sketchy. Described here is a landmark but little-known Spanish-language neuropathological study of two patients with lathyrism of recent onset. Due to erroneous interpretations of Filimonov's influential work in 1926, it was assumed that spastic paraparesis of lathyrism was explained by destruction of Betz's pyramidal cells in the motor cortex. Contrary to present understanding, Betz cells and anterior horn cells were preserved, and pathological findings dominated by myelin loss were largely limited to pyramidal tracts in the lumbar cord. Thickening of the adventitia of capillaries and arterioles, together with proliferation of perivascular astrocytes, was found along the length of the spinal cord. Oliveras de la Riva proposed that the segmental spinal pathology arose because distal regions of elongate pyramidal tract axons are distant from their trophic center in the motor cortex, a view not far from the current distal axonopathy concept of lathyrism. In addition, we review the historical circumstances of Filimonov's work in Russia, a summary of the epidemic of lathyrism in Spain following its Civil War (1936-1939), and some historical aspects of the Cajal Institute in Madrid, where Oliveras de la Riva's work was carried out under the supervision of Fernando de Castro, one of Cajal's favorite students.

Lathyrism: has the scenario changed in 2013?

Lathyrism is now rarely seen as a clinical disease in general, medical or neurology outpatient departments, throughout the world. Eating patterns of seeds of Lathyrus sativus are still prevalent focal points in parts of the world. Question arises, why are we not seeing cases of lathyrism? Is it that the disease has changed its profile, with the changing socioeconomic status of the poor or underdeveloped or moderately developed countries? Is it that the seeds of lathyrus are less toxic now? Is it that the body defence against toxins of lathyrus has genetically modified? To find out answers to these interesting questions, an extensive questionnaire-based sampling was done among 1000 subjects from northern India to identify the human behaviour regarding the knowledge, attitude, and practices (KAPs) for L. sativus. Four clinically suspected cases of Lathyrism were also fully worked up. It was concluded that many areas of India are still being fed with lathyrus seeds, but not many cases have appeared. Many questions have to be answered, as to what has reduced the incidence of lathyrism.

Brain glutathione as a target for aetiological factors in neurolathyrism and konzo.

Both neurolathyrism and konzo are associated with the nutritional dependence of human populations on a single plant food. These diseases express themselves as chronic disorders of upper motor neurones, leading to signs and symptoms that characterise amyotrophic lateral sclerosis (motor neurone disease). The plant food associated with neurolathyrism is grass pea, which contains the neurotoxic ß-N-oxalyl-α,ß-diaminopropionic acid (ß-ODAP). The plant food associated with konzo is cassava, which may contain significant concentrations of cyanogenic glycosides and their degradation products. A monotonous diet of grass pea is likely to generate nutritional deficiencies; it is proposed that one of these, plasma methionine deficiency, may predispose neurones to the neurotoxic effects of ß-ODAP. Subjects suffering from konzo also have low concentrations of plasma methionine as a result of a dietary deficiency of this amino acid. However, the plasma cystine concentration is also compromised because cyanide released from cyanogenic glycosides in cassava probably reacts with plasma cystine non-enzymatically. The product of this reaction is 2-imino-4-thiazolidine carboxylic acid. Since both plasma methionine and cystine are used for glutathione synthesis it seems likely that one common feature that leads to motor neurone death in neurolathyrism and konzo is the depletion of glutathione in the central nervous system.

Grass pea and neurolathyrism: farmers' perception on its consumption and protective measure in North Shewa, Ethiopia.

Neurolathyrism in Ethiopia is caused by food dependency on grass pea (Lathyrus sativus L.). In the study area, a large proportion of the farmers are growing grass pea since it can withstand harsh environments. Socio-economic factors (poverty; lack of money to buy other food legumes) and environmental problems (such as water logging and frost hazards) influence consumption of grass pea. Most of the respondents have the idea that some chemical contained in grass pea causes a health problem. Different processing and preparation methods are used to prepare grass pea into different food forms. The major processing methods include washing and soaking, as the farmers apply these methods mainly because they assume that the chemical that causes lathyrism, scientifically known as ß-ODAP (ß-N-oxalyl-L-α,ß-diaminopropionic acid) is reduced through washing and soaking. The farmers adopt different strategies to avoid the problem of lathyrism such as avoiding consumption of grass pea in the form that they suspect to cause the problem, blending/mixing with other crops, applying different processing/detoxification methods. Since grass pea is consumed with a fear of lathyrism, future research should concentrate either on developing grass pea varieties with safe level of ß-ODAP content or improving the traditional/indigenous processing methods.

Studies on neurolathyrism in Ethiopia: dietary habits, perception of risks and prevention.

This study describes the correlation of traditional perceptions and dietary habits with the incidence of neurolathyrism to propose preventive measures. Therefore, 118 households of South Wollo and North Gondar (Amhara Regional State, Ethiopia), of which one third had at least one neurolathyrism affected member, were interviewed. Most of the affected families in this study had one neurolathyrism victim, being predominantly male and of younger age. The incidence among youngsters (boys and girls) was significantly correlated with the consumption of green unripe seeds (eshet), confirming this as a risk factor for developing neurolathyrism. The consumption of other popular grass pea preparations was not age related. Neurolathyrism patients did not attempt any medication as most people knew that neurolathyrism is incurable, but the consumption of grass pea was abandoned after developing the disease. The minority 'Woito' tribe was virtually unaffected. They were the only people reporting to consume fish which is rich in amino acids such as methionine and using metallic kitchen utensils in addition to clay pots. This observation points to the correlation between low neurolathyrism incidence and a better balanced diet as well as metallic kitchen utensils, suggesting a new approach for neurolathyrism prevention.

Genetic improvement of grass pea for low neurotoxin (ß-ODAP) content.

Grass pea is a promising crop for adaptation under climate change because of its tolerance to drought, water-logging and salinity, and being almost free from insect-pests and diseases. In spite of such virtues, global area under its cultivation has decreased because of ban on its cultivation in many countries. The ban is imposed due to its association with neurolathyrism, a non-reversible neurological disorder in humans and animals due to presence of neurotoxin, ß-N-oxalyl-L-α,ß-diaminopropionic acid (ß-ODAP) in its seedlings and seeds. The traditional varieties of grass pea contain 0.5-2.5% ß-ODAP. Exploitable genetic variability for ß-ODAP has been observed for development of low ODAP varieties, which along with improved agronomic and detoxification practices can help reduce the risk of lathyrism. Collaborative efforts between ICARDA and NARS have resulted in development of improved varieties such as Wasie in Ethiopia, Ratan, Prateek and Mahateora in India, and BARI Khesari-1 and BARI Khesari-2 in Bangladesh with <0.10% ß-ODAP. Soil application of 15-20 kg ha(-1) zinc sulphate, early planting, and soaking seeds in water have shown significant effects on ß-ODAP. Because of the often cross-pollination nature, the current breeding procedures being followed in grass pea requires paradigm shift in its approach for a possible genetic breakthrough.

Neurolathyrism risk depends on type of grass pea preparation and on mixing with cereals and antioxidants.

OBJECTIVE: To study an array of household individual and dietary risk factors for neurolathyrism. METHOD: Case-control study using recent cases in a district highly affected by the recent neurolathyrism epidemic in Ethiopia: 108 households with cases and 104 households with no cases; 170 neurolathyrism cases, 370 intra-family controls and 170 community controls frequency matched for age and sex. RESULTS: A history of acute illness was associated with a two- and threefold increased risk of paralysis in community and intra-family controls, respectively. Soaking grass pea in water before cooking roughly halved the risk of neurolathyrism but cooking in clay utensils more than quadrupled it. Consumption of grass pea in the green unripe and boiled forms increased the risk 10 times or more. Mixing the food with gravy that contains condiments with antioxidant activity reduced it by a factor of 4. The consumption of grass pea mixed with cereals rich in sulphur amino acids was also highly protective, but the magnitude of the effect depended on the grass pea preparation consumed. CONCLUSION: Consumption of pure grass pea, especially in the green unripe and boiled forms, should be avoided. Communities at risk of neurolathyrism during famine crises should be encouraged to combine and use grass pea with cereals before the household cereal stock is fully depleted. Breeding programmes, alongside traditional attempts to reduce the toxin content, should enhance the content of sulphur amino acids and antioxidants in grass pea.

Neurolathyrism in Ethiopia: assessment and comparison of knowledge and attitude of health workers and rural inhabitants.

A cross sectional community based study was done in the Amhara Regional State of Ethiopia in 1999-2000 to assess and compare knowledge and attitude towards neurolathyrism among health workers and the rural community. A sample of 217 health workers selected by probability proportional to size and randomly selected 589 heads of household from a rural district were interviewed using pre-tested questionnaires. Neurolathyrism was widely known among the health workers and the community. More than half of community respondents associated the disorder with walking or lying on the straw and the stalks of grass pea. In a multivariate analysis. poor neurolathyrism knowledge among the community was associated with illiteracy and with presence of a neurolathyrism patient at home. Among health workers, contact with vapour or steam of grass pea foods was the commonest cause cited. In a multivariate analysis nurses had the poorest knowledge among the health workers. Depending on the subject, health workers and community respondents had more or less knowledge than the other. The prevailing recurrent adverse climatic conditions might promote grass pea as a 'friendly' crop to the poor peasants in marginal areas who otherwise rely on it only during times of food shortages and could increase the incidence of neurolathyrism. The poor knowledge among health workers and the community and the general neglect of neurolathyrism requires urgent intervention. Appropriate strategies for the dissemination of information education, and communication (IEC) are needed.

Pattern and associated factors of the neurolathyrism epidemic in Ethiopia.

OBJECTIVES: To describe the neurolathyrism epidemic in Ethiopia and to identify associated household factors. METHODS: We interviewed 589 randomly selected heads of household in Debre Sina district of Ethiopia, the area afflicted by the recent neurolathyrism epidemic. Disease information was obtained for 2987 family members. RESULTS: Neurolathyrism patients were detected in 56 (9.5%) households (prevalence rate 2.38%). The mean number of affected family members per household was 1.27 (SD 0.65, range 1-3). Most (77.5%) patients developed the disability during the epidemic (1995-1999). The median age at onset of paralysis was 11 years with a range of 41 (range 3-44). Younger people were more affected during the epidemic than during the non-epidemic period (P=0.01). The presence of a neurolathyrism patient in the family was associated with illiteracy [adjusted OR (95% CI)=2.23 (1.07-5.10)] of the head of household, with owning a grass pea farm [adjusted OR (95% CI)=2.01 (1.04-3.88)] and with the exclusive cooking of grass pea foods using handmade traditional clay pots [adjusted OR (95% CI=2.06 (1.08-3.90)]. CONCLUSION: Males aged 10-14 years were most affected by neurolathyrism. Increased household risk was associated with illiteracy of the head of the household and exclusive cooking of grass pea foods with handmade traditional clay pots.