人獣共通感染症連続講座(山内一也)(第154回 追加分) 2004.2.22
[米国のBSE:プルシナー博士の議会での発言]邦訳に対する
「読者からのコメントとそれに対する回答」
【読者からのコメント】
首記の邦訳全文拝読させて頂きました。全体として正確な翻訳であると
感じました が、この翻訳には 致命的な不親切さがあります。1996年以降
のBSEやプリオンの研究によってプリオン蛋白には、正常型 (以下正常プ
リオンと言います)と異常型(以下異常プリオンと言います)に分類されて、
食物連鎖としてBSEやTSEの媒体となるのは異常プリオンであることが報
告されてきています。しかるにこの翻訳では、何の注釈も補足もなく、『プ
リオンがBSEの原因』と言うちょっと信じ難い 翻訳になっています。
プルシナー博士はプリオンの概念を唱えた第1人者であるだけに、本当
にこの翻訳のような演説を行ったのか疑問を感じます。欧米の方々は、
言葉や概念を極めて正確に使用します。広義の概念なのか、狭義の概念
なのか、それを使い分ける必要がある場合は、必ず定義や注釈や補足
説明を入れます。講演や演説 、まして宣誓して議会証言するような場合
はそのような用意周到な配慮を欠かすと命取りとなります。 残念ながら、
この翻訳の英文原文が手元にありませんので何とも言えませんが、原文
には、何の注釈も補足もないのでしょうか?プルシナー博士がこの発言
で用いるターミノロジーとして「プリオンと言う場合、異常プリオンを意味す
る」とか「本日の講演では、異常プリオンによってひき起こされるBSE等の
感染症を簡単に『プリオン病』と表現し、この講演で簡単に『プリオン』と言
う場合、概して異常 プリオンを意味します」と言う断わりが、発言記録原
文のどこかになかったのでしょうか?!
小生は仕事柄重大な関心をもってプリオンの概念を見てまいりました。
小生を含めて素人や一般人にプリオン概念をできるだけ正しく科学的に
理解してもらうためには、プリオン概念の提唱者であり 第一人者である
プルシナー博士が、何の注釈もなくこの邦訳文のような大雑把な発言を
行ったとは信じられません。
先日、NHKの子供向けテレビサイエンス番組のHPにも、「プリオンがB
SEと言う狂牛病の原因だ」と記載されていることに気づきましたので、プ
リオンの概念をもう少し正確に解説し、正常プリオンと異常 プリオンのう
ち、食物連鎖の感染源と考えられているのは異常プリオンであると説明
するほうが、子供達にもプリオンの概念をより正確に伝えられるのでは、
と投書しました。
専門学会(注:日本獣医学会)のホームページで開示された翻訳に対し
て、小生のような専門外の者が意見を申し上げるのは勇気のいることで
す。常々海外資料や契約書や研究論文などを自分が翻訳してきた長年
の経験だけを 頼りに意見を申し上げさせていただいた次第です。
【回答】
プルシナーの米国議会での発言の翻訳について、読者から上記のコメ
ントが寄せられました。プリオンという用語についてです。私は著書や講
演会でいつも、マスコミ主導で行われている異常プリオン、正常プリオン
という表現が間違っていると指摘してきていました。しかし、ついに、その
間違った表現が今回のコメントに見られるような大きな誤解につながって
しまったことに愕然としています。紹介されているNHKの番組での表現は
正確で、読者のような解釈が子供に伝えられると、試験問題で正しい回
答が誤りにされてしまうおそれすらあります。
このコメントに対する回答として、私の著書「プリオン病の謎に迫る」
(NHKブックス)91ページの部分を転載します。
「プリオンとは病原体の種類をあらわす言葉として提唱されたもので、
ウイルス、細菌、寄生虫といった言葉に相当する。そして、プリオンの構
成成分は異常プリオンタンパク質であって、DNAのような核酸は含まれ
ていないと考えられている。
異常プリオンタンパク質は元来、身体の中に存在する正常プリオンタ
ンパク質の立体構造が変わったものである。日本ではいつのまにか、
正常プリオン、異常プリオンという言葉が定着してしまったが、正常ウイ
ルス、異常ウイルスという言葉が存在しないと同様に、この表現は正確
ではない。」
なお、プルシナーの発言は、ホームページ記事のように、議会下院の
食品安全委員会幹事会(Food Safety Caucus of the House of
Representatives of the United States)での発言(Statement)であって、
宣誓しての証言(Oath)ではないと思います。
今回の翻訳にあたっては、なるべくプルシナーの話の雰囲気を伝える
ために、あえて意訳は行いませんでした。
念のために、英文全文を添付します。
Statement from Stanley B. Prusiner, M.D., about 'Mad Cow'
disease in the United States - January 27, 2004
Thank you, I am pleased to be here to address the Food Safety Caucus
of The House of Representatives of the United States Congress about
Mad Cow disease. I appear here as a concerned citizen, a loving parent,
a Dedicated physician specializing in Neurology, an educator who is a
Professor of Neurology at the University of California, and scientist-
businessman who is the Founder of InPro Biotechnology. I am also an
expert on prion diseases, one of which is Mad Cow disease or bovine
spongiform encephalopathy, often-abbreviated BSE. Both Federal and
State Governments now find themselves embroiled over concerns over
Mad Cow disease after Secretary of Agriculture, Ann Veneman,
announced on December 23, 2003, that a 6.5-year-old cow from
Mabton, Washington, had been diagnosed with Mad Cow disease.
I would like to discuss five points concerning Mad Cow disease and
what I believe should be done in our country to combat this malady.
1. Prions cause Mad Cow disease: First, Mad Cow disease is caused by
an infectious agent that is so small that it cannot even be seen with the
most powerful microscopes. These small infectious agents are called
prions. Although large aggregates of prions can be studied with
electron microscopes, we still cannot see the individual prions.
For more than a century, viruses that can be seen in the electron
microscope were the smallest known microbes. But, prions are much
smaller than viruses and this extremely small size makes prions
extremely difficult to kill.
2. Prion disease is always fatal: Second, prions cause severe destruction
of the brain. The prion diseases of humans and animals are 100% fatal.
Indeed, everyone with prion disease eventually dies. A single prion is
sufficient to initiate the multiplication process that results in hundreds
of prions being made followed by thousands, then millions and finally
billions. It is well documented that billions of prions destroy the brain
and spinal cord.
From a wide variety of biomedical investigations, we know that prions
from cattle can infect humans and destroy their brains. More than
150 teenagers and young adults in Europe have died of prion disease
that they contracted after eating prion tainted beef or beef products.
3. Spontaneously induced prions: Third, prions arise spontaneously. This
is an extremely important concept; furthermore, the ability to arise
spontaneously is a feature that distinguishes prions from viruses.
Any mammal is capable of producing prions spontaneously.
In humans, the most common form of prion disease results from the
Spontaneous formation of prions. Despite decades of looking for prions
in the environment, there is no evidence for exposure to prions in
spontaneous cases of prion disease.
The initial event in an epidemic of human prion disease referred to as
kuru must have been a spontaneous case of prion disease. Once kuru
prions arose spontaneously, they were propagated by ritualistic
cannibalism that was practiced among New Guinea natives.
While halting cannibalism of dead relatives resulted in the
disappearance of kuru in a small population of natives, it did not
eliminate the spontaneous formation of human prions.
Similarly, stopping industrial cannibalism where cattle are fed the
rendered offal of other cattle has diminished the number of cattle
with BSE in Britain but will not prevent spontaneous prions from
being formed. Thus, while changing feeding practices for cattle will
stop the amplification of prions, it will not prevent the spontaneous
formation of bovine prions.
As I said, prions can develop spontaneously within any mammal.
We don't Know what triggers this process but there are several
reasonable hypotheses, one or more of which may eventually explain
the spontaneous formation of prions.
4. The Japanese solution: Fourth, I cannot understand as the father of
two daughters and the uncle of a niece and nephew why our country
remains unwilling to adopt the Japanese policy of testing every cow
and bull destined for consumption by humans. I have difficulty explaining
to these young people that the beef in Japan is safer than that in the
U.S. The United States has the same problem that the Japan has, but
the Japanese test all of the cattle that they slaughter. This issue
particularly troubles children when they learn that the time from
exposure to prions until the onset of neurological disease can exceed
50 years. Some New Guinea natives developed kuru more than 50
years after ingesting prions during cannibalistic feasts.
5. Prion science is new: Fifth, the science of prions is still very young.
Only 25 years ago, I discovered prions and named these unprecedented
infectious agents. Thus, the naysayers, who continue to deny the
existence of prions, should not surprise you. A chorus of naysayers
has always accompanied big changes in scientific thinking. When
Galileo wrote about the planets orbiting the sun, he was imprisoned.
How dare he think that the earth was not the center of universe?
From the time that Einstein proposed his special theory of relatively
in 1905 until his death 50 years later, the naysayers scorned him
almost daily. Each week, at least two or three letters arrived at his
Princeton office that declared him insane and his theories impossible.
Only his death terminated this non-sense! Philip Semelweiss, a
Viennese obstetrician, was eventually admitted to an insane asylum.
Semelweiss was ridiculed mercilessly for proposing that his 3 colleagues
could prevent deadly bacterial infections in mothers after childbirth
if they would only wash their hands between the deliveries of newborn
infants. And few believed Alfred Wagener when he proposed continental
drift as a mechanism to explain the shapes and positions of the
landmasses on our planet.
I recited a few instances of "scientific heresy" to place the discovery
of prions in some perspective for you. For much of my career, I faced
a legion of scientists who vehemently argued that prions couldn't exist!
They yelled, "prions are nonsense. They are impossible!" Twenty-five
years after my discovery of prions, there remain some people who are
still unable or unwilling to comprehend the novel concepts of prion
biology. The famous German physicist Max Planck encountered many
naysayers when he and others set forth the principles of quantum
mechanics. In frustration, Planck once remarked, "a new scientific
truth does not win out by convincing its opponents, rather they
eventually die off and a whole generation familiar with it grows up."
In non-scientific terms, prions must be considered new, strange
and scary microbes by any measure. Twenty-five years ago, there
were no prions - now the biology of prions is taught in every medical
school throughout the world. Prion biology is also taught in many
high schools and most colleges. Moreover, the word "prion" appears
in every dictionary. Because the discovery of prions ushered in major
changes in our thinking, your duties as Congresswomen and
Congressmen have and will continue to be subject to much
misinformation with respect to Mad Cow disease. But I hasten to
add that this is inevitable when an entirely new field of science
emerges. Despite the fact that prions were once branded scientific
heresy and are now considered orthodoxy by most scholars, the
naysayers still exist. This means that you and your staff will hear
some opinions that are not based on the body of scientific
knowledge that has been accumulated over the past quarter
century. Instead, you will hear views that ignore a constantly
enlarging body of scientific information that has been verified by
experimental studies.
Concluding remarks: In conclusion, from studies over the past
half-century, we know that people should not eat prions, particularly
prions of human or Bovine origin. I want to reiterate that the problem
of prion contamination in the food supply will not disappear. If we do
nothing, confidence in the safety of food supply will only continue to
erode. The sooner we face the problem of prion contamination, the
more easily we shall be able to contain it. Only the Japanese solution
of testing every slaughtered cow or bull will eliminate prions from the
food supply and restore consumer confidence. Certainly, the citizens
of the most prosperous and accomplished nation on our planet
deserve to eat meat that is devoid of prions...END
http://www.agobservatory.org/library/uploadedfiles/showfile.cfm? File name
=Statement_from_Stanley_B_Prusiner_MD_About_Mad.pdf
http://www.agobservatory.org/library/listcontent.cfm
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