Home Page Link AgBioWorld Home Page
About AgBioWorld Donations Ag-Biotech News Declaration Supporting Agricultural Biotechnology Ag-biotech Info Experts on Agricultural Biotechnology Contact Links Subscribe to AgBioView Home Page

AgBioView Archives

A daily collection of news and commentaries on

Subscribe AgBioView Subscribe

Search AgBioWorld Search

AgBioView Archives





May 7, 2000


RE: An African Student Pleads for Biotechnology


- http://www.agbioworld.org, http://agbioview.listbot.com

A reply to Remmy W. Kasili:

Dear Remmy:

One of the issues that could be addressed by biotechnology and which could
benefit many persons in Central Africa is the human health danger posed by
improperly prepared cassava (Manihot esculenta Cranz).

This shub whose roots and leaves are a dietary staple for 300-400 million
people worldwide, mainly in tropical and subtropical areas, is quite
nutritious and is both flood and drought resistant. However, when improperly
prepared (proper preparation takes 3-5 days of significant labor), the natural
toxins linamarin and lotaustralin contained in the plant break down into
acetone cyanohydrin, hydrogen cyanide, cyanate, etc. which are associated with
the following 4 serious health conditions:

1) Acute Cassava Poisoning (similar in all respects to acute cyanide
poisoning and which can be successfully treated with cyanide antidotes);

2) Goiter and congenital cretinism (from the human cyanide metabolite,
thiocyanate which mimics iodine, is taken up by the thyroid, and decreases
production of thyroid hormones causing all aspects of thyroid deficiency);

3) Tropical Ataxic Neuropathy (TAN): A typical dying-back anonopathy which
results in decreased sensory ability, weakness, and a feeling of pain or
"pins-and-needles" in the extremities; associated with a high prevalance of
nerve deafness and vision decrements, among other adverse effects;

4) Konzo: An upper motor neuron paraparesis with sudden onset which causes
severe crippling and which is completely untreatable.

Note that all these are the effects of NATURAL TOXINS. Nature can and will do
it to us. It also does NOT seem that these toxins account form insect or
disease resistance, nor flood or drought resistance in this plant. If the
production of these natural toxins could be bioengineered OUT of the cassava
plant, then hundreds of millions of persons now at risk could comsume it
safely without the arduous preparation currently needed to allow its safe use
as a dietary staple.

Much work on the toxicity of cassava has been done at the International Child
Health Unit, Uppsala University, Sweden, and I've had a bit to do with it
myself (I presented the above information at the VIIIth International Congress
of Toxicology in Paris in 1998, under the auspices of "Natural toxins which
are also important industrial chemicals").

Yours truly,

Alan H. Hall, M.D.
Medical Toxicologist


> your press release. However, my stand on the issue of Biotechnology is
> firm as ever. People who have never been to this part of the world can
> never understand problems our people go through. In Sub-saharan Africa,
> for example, the problem of food insecurity, malnutrition and poverty is