- Do you like imported sheep's milk cheeses, for example,
a special type of Feta or other cheeses made with sheep's milk? How
about cheeses made with goat's milk? Not that Feta cheese has prions,
of course, but there could be, theoretically speaking only, a rare
possibility that any product, whether it be cheese, kefir, yogurt,
protein powders, or ice cream made from sheep's or goat's milk anywhere
and imported to the USA, or made in the USA could possibly be made
with milk that looks good to testing, but the sheep or goats might
20 months later develop symptoms of prion diseases without it showing
up before in tests.
-
- New evidence indicates that [scrapie] prions are secreted
in milk from clinically normal sheep that have been exposed to scrapie.
The important point is that it took 20 months for the scrapie symptoms
in the sheep to show up, but the prions were found in the milk long
before the scrapie symptoms appeared, according to a study reported
in the Journal of Virology, August, 2009. ["Prions Are Secreted in
Milk from Clinically Normal Scrapie-Exposed Sheep." B. C. Maddison,
C. A. Baker, H. C. Rees, L. A. Terry, L. Thorne, S. J. Bellworthy, G.
C. Whitelam, and K. C. Gough, Department of Biology, University of
Leicester, UK -- see full rference and Abstract of the paper below]
The authors of this study found that, "The potential spread of prion
infectivity in secreta is a crucial concern for prion disease transmission."
-
- According to the study, a "serial protein misfolding
cyclic amplification (sPMCA)" technique, allowed the detection
of prions in milk. These data indicate the secretion of prions within
milk during the early stages of disease progression and a role for
milk in prion transmission. So now it is possible, the study found,
to find prions in sheep's milk, if the sheep are affected with prions
but don't show symptoms yet. According to the sudy: "Furthermore,
the application of sPMCA to milk samples offers a noninvasive methodology
to detect scrapie during preclinical/subclinical disease."
-
- If scientists want a noninvasive methodology to find
scrapie prions in sheep before the sheep come down with symptoms,
what the medical world calls the preclinical or subclinical disease
stages, more milk samples need to be tested.
-
- For further information, also see the article based on
a study, "Prion Disease Spreads Through Sheep's Milk,"
published in the 16 April 2008 issue of New Scientist.
-
-
- http://www.newscientist.com/article/mg19826513.900-p
- rion-disease-spreads-through-sheep-milk.html
-
-
- According to the article, "Experiments on lambs
genetically predisposed to developing scrapie provided the proof."
Gut tissues from 2 out of 3 culled "scrapie-fed" lambs
were positive for scrapie, as were biopsies from the rectums of the
15 surviving scrapie-fed animals. The study noted, "Rectal samples
from controls were negative, implying that milk spread the disease."
However, numerous scientists still insist that prion diseases do
not spread to humans through animal's milk (1).
-
- Using the technology developed by Allprion to detect
(Allprion PrioMax) and to remove (Allprion PrioMin) prion protein
from body fluid, we are able to show that PrPC is present in milk
from humans, cows, sheep, and goats." The Prion Protein in Milk
article based on studies noted, "The absolute amount of PrPC
differs between the species, from mg/l range in sheep milk, to ng/l
range in human milk. Off-the-shelf milk contains significant amounts
of endogenous prion protein even after ultra-high temperature treatment."
-
- So, cooking won't kill the prions. The Prion Protein
in Milk article based on studies noted, "In view of a recent
study showing evidence of prion replication occurring in the mammary
gland of scrapie infected sheep suffering from mastitis (2)2, the
appearance of PrPC in milk implies the possibility that milk of TSE-infected
animals serves as a source for PrPSc. allprion PrioMax allows the
study of the biosafety of milk with regard to TSE risk. Such studies
were recently recommended by the European Commission and the European
Food Safety Authority (reference 3 below)."
-
- References
-
- 1. Ironside, J.W., et al. Variant Creutzfeldt-Jakob disease:
risk of transmission by blood and blood products. Haemophilia 10
Suppl. 4, 64 (2004). 2. Ligios C, et al. PrPSc in mammary glands of sheep
affected by scrapie and mastitis. Nature Med. 11, 1137 (2005). 3.
Statement of the European Food Safety Authority on the health risks
of the consumption of milk and milk derived products from goats (2004).
Last updated 15 March 2006.
-
-
- ______
-
- Communicated by ProMED-mail Rapporteur Susan Baekeland
-
- [The following is the abstract of the paper on which
the preceeding report is principally based.
-
- Ref: Prions Are Secreted in Milk from Clinically Normal
Scrapie-Exposed Sheep. Journal of Virology, August 2009, p. 8293-8296,
Vol. 83, No. 1 http://jvi.asm.org/cgi/content/abstract/83/16/8293
-
-
- ----------------------------------------------------
-
-
- Authors: B. C. Maddison,1 C. A. Baker,1 H. C. Rees,2
L. A. Terry,3 L. Thorne,3 S. J. Bellworthy,3 G. C. Whitelam,2 and
K. C. Gough4* At: ADAS UK, Department of Biology, University of Leicester,
University Road, Leicester LE1 7RH, United Kingdom,1 Department of
Biology, University of Leicester, University Road, Leicester LE1 7RH,
United Kingdom,2 Veterinary Laboratories Agency, Woodham Lane, New
Haw, Addlestone, Surrey KT15 3NB, United Kingdom,3 School of Veterinary
Medicine and Science, The University of Nottingham, Sutton Bonington
Campus, College Road, Sutton Bonington, Leicestershire LE12 5RD,
United Kingdom4
-
- Abstract: "The potential spread of prion infectivity
in secreta is a crucial concern for prion disease transmission. Here,
serial protein misfolding cyclic amplification (sPMCA) allowed the
detection of prions in milk from clinically affected animals as well
as scrapie-exposed sheep at least 20 months before clinical onset
of disease, irrespective of the immunohistochemical detection of
protease-resistant PrPSc within lymphoreticular and central nervous
system tissues. These data indicate the secretion of prions within
milk during the early stages of disease progression and a role for
milk in prion transmission. Furthermore, the application of sPMCA to
milk samples offers a noninvasive methodology to detect scrapie during
preclinical/subclinical disease."
-
- It should be stressed that irrespective of the presence
or absence of the scrapie prion in the milk of sheep, up to the present
there has been no evidence to suggest humans are susceptible to infection
by [an unmodified] scrapie agent. - Mod.CP]
-
- [The interactive HealthMap/ProMED map is available at:
<http://healthmap.org/promed/en>http://healthmap.org/promed/en -
CopyEd.EJP]
-
- Patricia A. Doyle DVM, PhD Bus Admin, Tropical Agricultural
Economics Univ of West Indies Please visit my "Emerging Diseases"
message board at: http://www.emergingdisease.org/phpbb/index.php Also my
new website: http://drpdoyle.tripod.com/ Zhan le Devlesa tai sastimasa
Go with God and in Good Health
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