Published Date: 2003-10-07 23:50:00
Subject: PRO/AH/EDR> BSE - Japan (04): atypical
Archive Number: 20031007.2511
BSE - JAPAN (04): ATYPICAL
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Tue, 7 Oct 2003
From: ProMED-mail <email@example.com>
Source: Japan Times, 7 Oct 2003 [edited]
Ibaraki bull confirmed as having mad cow disease
A Holstein bull slaughtered in Ibaraki Prefecture [in September 2003]
was confirmed Monday to have been infected with mad cow disease.
The 23-month-old bull is the 8th case of the brain-wasting illness
found in Japan and is believed to be the world's youngest carrier of
the disease, also known as bovine spongiform encephalopathy [BSE],
according to the Health, Labor and Welfare Ministry [MHLW].
The bull was brought to the slaughterhouse 29 Sep 2003; 2 separate
sets of tests carried out by Ibaraki health officials and the
National Institute of Infectious Diseases raised concerns about
possible mad cow contamination. On Monday evening, a panel of
experts at the health ministry positively diagnosed the bull as
having the disease. It also said the abnormal prions found in the
bull were of a different type from those of any of the mad cow
infection cases reported worldwide so far.
The bull was born in October 2001 and was younger than the 7 beasts
previously diagnosed with mad cow disease, the latest of which was
confirmed in late January 2003. Until now, the youngest infected cow
here was 64 months old. Since May 2002, the animal had lived at a
farm in Katsurao, Fukushima Prefecture. It was previously kept on a
farm in Otawara, Tochigi Prefecture, though it was not immediately
clear whether the bull was born there.
Prions -- protein particles lacking nucleic acid that are suspected
of transmitting the malady -- are believed to accumulate mainly in
older cattle. Cows examined in Europe for the disease are generally
older than 24 months.
Mad cow disease is believed to be caused by the consumption of
meat-and-bone meal contaminated with abnormal prions. It has been
linked to nervous system illnesses [in man] such as Creutzfeldt-Jakob
Japan's first case was confirmed in September 2001 in Chiba
Prefecture. The other cases turned up in Hokkaido, Gunma, Kanagawa
and Wakayama prefectures. Last month, a panel of the Agriculture,
Forestry and Fisheries Ministry said the source of the outbreak in
Japan was either cows imported from Britain in the 1980s or
Italian-made meat-and-bone meal imported before 1990, noting they
caused secondary infections through domestic cattle.
The panel had been probing the infection route since November 2002
but was unable to determine which of the 2 sources was responsible.
It said there could be over 30 additional animals in Japan with mad
cow disease, which first broke out in 1986 in Britain.
The fact that the bull, which was born after the first domestic case
came to light, was confirmed as having the disease indicates that
there may be another route of contamination, experts said.
[Unlike other countries, Japan has a BSE sche
me that prescribes the testing of all slaughtered animals, all ages --
including animals younger than 30 and 24 months, arriving at
slaughterhouses. During the current year (up to 27 Sep 2003), out of a total
887 261 bovines reportedly examined, the majority (529 795) were under the
age of 30 months. This may explain the enhanced odds for the detection of a
positive BSE case in a young, allegedly symptomless animal (see item 
below), compared to other countries. It may also justify Japan's decision to
include young animals in the testing scheme.
Regarding "another route of contamination", the reader may be
referred to previous postings in which the hypothetical contamination
of calf milk replacers was discussed. Other routes have been
discussed as well. - Mod.AS]
Date: Tue, 7 Oct 2003
From: Jun-ichi Ohnishi <firstname.lastname@example.org>
As you already know, Japan has detected the 8th case [of BSE], a
23-month-old bull. MHLW reports that this case is exceptional not
only in the animal's age but also in the points detailed below (dated
6 Oct 2003).
1. A western blot detected prions, while histopathology and
immunohistochemistry were negative. (The 3 methods are for the
2. In the western blot, glycosylation pattern and protease
sensitivity were different from the other cases.
I summarize below the details about the bull (shown in the upper part
of the said page)[In Japanese]:
The bull's (date of birth: 25 Oct, 2001) not shown on this page.
Date of slaughter: 29 Sep 2003.
23 months of age
Screened in the [North branch of the Ibaraki meat testing facility],
Confirmed at the National Institute of Infectious Diseases [Japan].
Although I [am not certain of] the full details of the explanation
for the blots, it seems that they are using 2 types of antiserum.
Lanes 1-3 and 9-11 are controls; lanes 5 and 6 show the protease
sensitivity. If so, the glycosylation pattern in lanes 7 and 8 is
surely different from the lanes 9-11: the lowest unglycosylated band
Tel: 048-858-3397 Fax: 048-858-3384
[Readers are referred to the Japanese web-site, where histochemistry
and western blots referred to above are displayed.
In view of the exceptional nature of this case -- especially the
negative histochemistry -- and its potential implications in a global
sense, one wonders whether the Japanese investigators might have
considered obtaining confirmation of the diagnosis from an
international reference laboratory. Authoritative commentary on the
displayed findings will be welcomed.- Mod.AS]