ProMED-mail |

Published Date: 2002-10-20 23:50:00
Subject: PRO/AH> BSE - update (12) October 2002
Archive Number: 20021020.5606

BSE - UPDATE (12) OCTOBER 2002
*******************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
In this update:
[1] Third BSE case in Poland - age unknown
[2] A new estimate of the extent of BSE infections
[3] BSE Infectivity in bovine tonsil
[4] Australia/New Zealand's precautions re tallow and gelatine
[5] Czech consumers in view of fourth BSE case

[1]
Date: Sat, 20 Oct 2002
From: ProMED-mail <promed@promedmail.org>
Source: OIE, Disease Information Vol. 15, No. 41, 11 Oct 2002 [edited]
<http://www.oie.int/eng/info/hebdo/AIS_50.HTM#Sec3>

Bovine Spongiform Encephalopathy in Poland
-------------------------------------------
Additional information on the third case.
Information received on 7 and 10 Oct 2002 from Dr Piotr Kolodziej,
Chief Veterinary Officer, Ministry of Agriculture and Rural
Development, Warsaw.
End of previous report period: 30 Sep 2002 (see Disease Information,
15 [40], 193, dated 4 Oct 2002).
End of this report period: 10 Oct 2002.
The cohort of the affected cow was defined as all animals born on the
farm up to one year before and one year after the affected cow. All
these cows were traced and were all on the farm. The cohort included
63 cows. A total of 32 cows were killed and destroyed; as the other
31 cows were in late pregnancy they will be killed and destroyed
after calving.
[The Polish authorities have not disclosed the age of the affected
cow. Reportedly, the first two positive cases in Poland were 12 and 8
years old. Should the age of the third case be lower (as might be
suspected -- while ProMED-mail welcomes corrective, authoritative
information -- from the relatively large size of the age cohorts),
this might be indicative for recent infection with worrying
consequences. For background, the reader is referred to predictions
on BSE infection rates in Greece, Italy, and Belgium in article [2]
of this update. Mod. AS].

******
[2]
Date: Sat, 20 Oct 2002
From: ProMED-mail <promed@promedmail.org>
Source: The Royal Society, press release, 08 Oct 2002 [edited]
<http://www.pubs.royalsoc.ac.uk/>

Implications of BSE infection screening data for the scale of the
British BSE epidemic and current European infection levels
------------------------------------------------------------------------------------------------
Researchers (CA Donnelly, NM Ferguson, AC Ghani and RM Anderson) from
Imperial College London have published new results that suggest that
over half of BSE cases went unrecognised or unreported during the
epidemic in Great Britain.
The new figures, to be published in a forthcoming Proceedings B, a
learned journal published by the Royal Society, estimate that the
total number of cattle infected during the epidemic was over two
million. However the paper highlights the need for additional
research to reduce the uncertainties in some key biological factors
underlying this estimate.
The researchers estimate that the new results will not have an effect
on the predicted size of the new variant Creutzfeldt-Jakob Disease
[abbreviated as vCJD or CJD (new var.) in ProMED-mail] epidemic in
humans as the results indicate that the probability of human
infection from eating BSE-infected meat from an individual infected
animal is lower than previously thought.
"Our results demonstrate the effectiveness of the additional control
measures implemented in Great Britain in 1996 after the
identification of vCJD," concludes Prof. Donnelly. "It also provides
a standardised framework for comparing BSE infection levels in
different EU countries. Furthermore it suggests that some countries
with few confirmed cases but relatively high recent infection risks,
such as Greece, Italy and Belgium, may warrant additional control and
enforcement measures. This will reduce future case numbers in these
countries and avoid prolonging the course of these epidemics."
Estimates are also made of the per-head incidence of infection in
cattle born between 1993 and 1997 in other European countries.
Comparative data for cattle born after mid 1996 indicates relatively
high infection in Greece, Italy and Belgium. Spain and the
Netherlands show intermediate levels, whilst the incidence in Great
Britain, Germany and France is comparably low. European data from
EU-wide testing of apparently healthy cattle over 30 months old
cattle and slaughtered for consumption were analysed to place the
British results in context. Although infection rates in other
countries are low relative to the peak of the epidemic in Britain,
there are significant variations.
The study used backcalculation methods adapted for analysis of BSE
from those originally developed in the early years of the HIV/AIDS
epidemic. Previous work was extended to allow integrated analysis of
available data on clinical case incidence and the results from
screening of apparently healthy cattle to obtain estimates of case
rates.
"Two possible mechanisms for underreporting were examined," says
Prof. Christl Donnelly of Imperial College London. "Underreporting of
clinical cases and differential slaughtering of BSE-infected animals
prior to clinical manifestation of the disease due to, for example,
possible productivity effects of the disease - for example reduced
milk yield."
In both models new estimates for the extent of infection in Great
Britain are markedly above previous figures. "The best fit to the
screening data is obtained with the differential slaughter model, and
shows 1.9 million cattle were infected during the epidemic. 1.6
million of these were slaughtered for consumption before onset of
clinical signs of disease," says Prof. Donnelly. "This compares with
estimates of 1.05 million infections and 0.87 million infected cattle
slaughtered for consumption if the possibility of differential
survivorship or ongoing under-reporting is not allowed for."

******
[3]
Date: Sat, 20 Oct 2002
From: ProMED-mail <promed@promedmail.org>
Source: Food standards Agency's BSE Review, 17 Oct 2002 [edited]
<http://www.bsereview.org.uk/templates/latest/item.cfm/164>
[Item on same subject has been received from Pablo Nart]
BSE Infectivity found in bovine tonsil
--------------------------------------
Preliminary results from research sponsored by the Food Standards
Agency have, for the first time, found BSE infectivity in cow tonsil.
Current controls require all cow tonsil to be removed from meat
intended for human consumption.
The new tests, which are considered to be several hundred times more
sensitive than those previously applied using mice, involve the
injection of a range of tissues from infected cattle into BSE-free
cows to determine if they carry infectivity.
One out of five cows has gone down with BSE, 45 months after they
were injected with tonsil tissue samples collected from the infected
cattle. The long incubation period indicates that the level of
infectivity in tonsil is relatively low.
Tonsil tissue from cattle previously tested using mice has not been
shown to carry infectivity. However as a precautionary measure, EU
wide legislation classifies bovine tonsil over a certain age as
specified risk material (SRM). It is banned from the food chain in
the UK and Portugal from cattle over six months of age, and from
cattle over 12 months of age in other EU countries. The same SRM
rules require tonsil to be stained and destroyed once removed.
Under separate EU wide hygiene regulations, tonsil from cattle of any
age cannot enter the food chain. Controls on bovine offal, including
tonsil, were first introduced in England and Wales in 1989.
It is known that tonsil tissue can be found at the root of the
tongue. A limited initial study of current practice has already
indicated that tonsil tissue does not appear to remain on tongues
prepared for human consumption. Tongue is not SRM and can enter the
food chain.
The Agency plans to assess the way in which tongue is extracted, in
particular to see whether any traces of tonsil tissue might be
inadvertently included with tongue.
The results from these further investigations into the way bovine
tongues are removed will form part of a risk assessment to be
considered by the Government's BSE advisory committee, SEAC.
Decisions on whether any further precautionary action might be
required will be taken following that assessment.
The risk of BSE entering the food chain from UK cattle is low. Only
cattle under 30 months can enter the UK food chain at present and no
BSE case has been diagnosed in animals under this age in the UK since
1997.
The latest report from Imperial College estimates that, in the year
2000, less than one animal close to developing disease would have
entered the food chain. In addition, SRM controls remove some 95
percent of potentially infected material from cattle, providing
important consumer protection.
The Agency has informed the European Commission of the finding and
its plans for further work.
[It will be interesting to note if and what precautionary action will
be recommended by the Scientific Steering Committee (SSC) of the EU,
in view of these observations, specifically concerning the use of
bovine tongues for human consumption. -Mod. AS].

******
[4]
Date: Sat, 20 Oct 2002
From: ProMED-mail <promed@promedmail.org>
Source: Just-food.Com, 03 Oct 2002 [edited]
<http://just-food.com/news_detail.asp?art=51840>

AUSTRALIA/NEW ZEALAND: Food watchdog calls for extension to beef ban
to tallow, gelatine
----------------------------------------------------------------------------------------
Food Standards Australia New Zealand (FSANZ) yesterday [Wed, 02 Oct
2002] called for further restrictions to beef imports to ramp up the
region's protection against BSE (bovine spongiform encephalopathy,
commonly known as mad cow disease). The agency said it wanted to
restrict shipments of tallow and gelatine derived from bone. The new
restrictions would come on top of those already in place, which
effectively ban meat imports from countries including EU member
states. The new restrictions would hit importers of ice cream, jelly
and confectionery products that use bulk tallow and bone-derived
gelatine.
[The European SSC is due to discuss the quantitative assessment of
the BSE risk of tallow and gelatine during a meeting on 7-8 Nov 2002.
- Mod. AS]

******
[5]
Date: Sat, 20 Oct 2002
From: ProMED-mail <promed@promedmail.org>
Source: Czech Radio Newsview, 15 Oct 2002 [edited]
<http://www.radio.cz/en/article/33368>

Public confident BSE is not a high-risk threat
----------------------------------------------
The sizzle has by no means not gone out of Czech beef - that despite
the fact that two new cases of BSE, or mad cow disease, were
confirmed in Czech cattle earlier this month. The State Veterinary
Office took immediate steps in monitoring the situation and had the
infected 7 years-old cow put down along with 25 other animals and
beef deliveries from the farm temporarily stopped as a precautionary
measure. Meanwhile, there has been no indication in a drop of in beef
sales, consumer confidence remains high.
Only 4 animals out of 250 000 have tested positive since 2001, and
tighter restrictions and regulations regarding meat inspections
testing as well as overall animal breeding, cattle-feed, and the sale
and import of meat products, make it unlikely an unsafe piece of
Czech beef could make it to the dinner table.
Josef Duben of the Czech Veterinary Office: "We have always informed
consumers that they could be confident in the quality of our
veterinary checks. All the meat that makes it to shopkeepers' shelves
has been tested. All cows 30 months or older are tested for BSE,
younger specimens are not, in keeping with EU regulations. No
infected product should be able to make it onto the shelves."
Josef Duben believes that while it is important to take the BSE
threat seriously it is not a high risk situation. He indicates that
the cows that tested positive in the Czech Republic were born in the
years 1995 - 1997, which he believes were part of a wider trend
throughout Europe when a wider range of animals on the continent were
infected because they were all fed infected bone-meal from Britain,
available on the European market at that time. Because regulations
were tightened since then, Mr Duben says it seems unlikely too many
new cases of mad cow disease should appear in the Czech Republic,
although obviously they can not be completely ruled out. Finally, Mr
Duben stresses that even though 4 cases of BSE have been confirmed in
cows in the Czech Republic, there has never been a confirmed case of
the related and fatal human illness known as Creuzfeld-Jacobs.

[Byline Jan Velinger]
--
ProMED-mail
<promed@promedmail.org>
[In another press item (The Prague Post, 16 Oct 2002) it has been
stated that "last year, Czech consumers quickly reacted to news of
the infections. Within weeks, beef sales plunged 30 percent below
normal levels, according to the Czech Meat Producers Union. However,
this year's outbreak has not had the same effect".
The fourth BSE case in the Czech republic seems not to have been
officially confirmed to the OIE, since it does not appear on their
BSE table. - Mod.AS]

See Also