Thursday, May 20, 2010

Whats is Lathyrism? Symptoms and Preventions of Lathyrism

Lathyrism, is a crippling disease characterized by paralysis of the leg muscles occurring mostly in adults consuming large quantities of the seeds of L-sativus(Lathyrus sativus) or other lathyrus species over long periods.  In India, the disease occurs in Madhya Pradesh, Bihar, and Uttar Pradesh.  The disease has also been reported to occur in Spain, Algeria and occasionally in certain parts of France and Italy where lathyrus peas are consumed by the people. 

Signs and Symptoms of Lathyrism
Acton has described four stages of the development of the disease in human beings.  The first stage is characterized by weakness of the lower limbs with spasticity of leg muscles so that movement at the ankle and knee joints is restricted and painful.  In the second stage, flexion of the knee is more marked and there is a certain amount of inversion of food with a tendency to talk on toes.  In the third stage, the symptoms described above become more marked and the subject can walk only with the help of crutches or sticks.  In the fourth stage, the knee becomes completely flexed and erect posture and walking becomes impossible.  There is atrophy of the thigh and leg muscles.

Identification of toxic factors in the lathyrus and the vicia species

Two types of lathyrism have been reported to occur in animals and human beings, viz., osteolathyrism where pathological changes occur in the bones resulting in skeletal deformities and neurolathyrism in which the muscles of the legs are paralyzed sometimes resulting in convulsions and death in severe cases.  Different species of lathyrus cause one or the other type of disease though sometimes both types may be caused by the same species.

Lathyrus sativus seeds have been implicated for a long time as responsible for lathyrism in some parts of India.  This disease is mainly of the neurological type.  The main neurotoxic substance was established as B-oxalylamino alanine.  This compound causes nervous derangement in young chicks but rats and mice are not appreciably affected.  This might be the reason for many of the earlier contradictory reports regarding the toxicity of the seeds of L-sativus when different test animals were employed.

There is now conclusive evidence that excessive consumption of L-sativus seeds is the cause of the high incidence of lathyrism in certain parts of India.  Although the harmful effects of L-sativus have been realized for some years, effective steps for the prevention of the disease have not so far been taken by the government.  There are three possible approaches for the eradication of the disease:

  • Treatment of the seed by leaching out the toxic factors in hot water both on home scale and factory scale.
  • Education of the public on the dangers of consuming untreated L-sativus and
  • Cultivation of other pulses in place of L-sativus.
Removal of toxic factors by leaching in water:  Acton was the first worker to point out that L-sativus seeds soaked in three changes of water are non-toxic.  Later workers have confirmed the above observation that the toxic factors present in L-sativus could be leached out in water.  It is evident that the toxic factors can be removed by
(1) Cooking the whole seed and decuticled seed in excess of water and draining the water and
(2) Steeping the whole seed or decuticled seed in hot water for 4 to 5 hours and rejecting the soak water.  The later process can be carried out on industrial scale and the resulting detoxified dhal could be sold to the people through ration shops and cooperative stores.

Public Awareness – There is urgent need for educating the public on the dangers of consuming of L-sativus seeds.  This should be done through leaflets distributed in schools, hospitals and municipality centers pointing out the dangers of consuming the untreated L-sativus seeds and the need for the removal of the toxin factors from the seed and dhal by steeping in hot water and rejecting the soak water.

Cultivation of other pulses in place of L-sativus – The governments of different states where lathyrism is prevalent should, if necessary, by enactment of law, enforce the cultivation of other pulses commonly grown in the region in place of L-sativus.

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