PRION DISEASE UPDATE 2009 (07)
In this update:
1. UK: National CJD Surveillance Unit - monthly statistics as of 3 Aug 2009
2. France: Institut de Veille Sanitaire - monthly statistics as of 4 Aug 2009
3. US National Prion Disease Center - not updated (quarterly statistics as of 15 May 2009)
4. Risk assessment
5. Blood transmitted vCJD
6. Species barrier
7. Scrapie prions in sheep milk
1. UK: National CJD Surveillance Unit - monthly statistics as of 3 Aug 2009
Date: Tue 4 Aug 2009
Source: UK National CJD Surveillance Unit, monthly statistics [edited]
<http://www.cjd.ed.ac.uk/
The number of suspected cases of vCJD referred to the CJD
surveillance unit in Edinburgh, and the number of deaths of definite
and probable cases due to vCJD remain unchanged since the previous
monthly report; that is, the number of deaths due to definite or
probable vCJD cases remains 164. A total of 4 definite/probable
patients remain alive, bringing the total number of definite or
probable vCJD cases to 168. No cases of vCJE have been reccorded
during the 1st 7 months of 2009.
This situation is consistent with the view that the vCJD outbreak in
the UK is in decline. The 1st cases were observed in 1995, and the
peak number of deaths was 28 in the year 2000, followed by 20 in
2001, 17 in 2002, 18 in 2003, 9 in 2004, 5 in 2005, 5 in 2006, 5 in
2007, only one in 2008, and none so far in 2009.
Totals for all types of CJD cases in the UK in the year 2009
------------------------------
As of Tue 3 Aug 2009 in the UK so far this year [2009], there have
been 80 referrals, 32 cases of sporadic CJD, one case of familial
CJD, one case of iatrogenic CJD, two cases of GSS, and no cases of vCJD.
2. France: Institut de Veille Sanitaire - monthly statistics as of
Tue 4 Aug 2009
Date: Tue 4 Aug 2009
Source: IVS - Maladie de Creutzfeldt-Jakob et maladies apparentees
[in French, trans. & summ. Mod.CP]
<http://www.invs.sante.fr/
Since the update in the preceding month, the suspected case of vCJD
has been confirmed and a new suspected case is listed.
So far in the 1st 7 months of 2009 there have been 83 referrals,
34 cases of sporadic CJD, 6 cases of familial CJD and no case of
iatrogenic CJD. There is currently one case of suspected vCJD (no
details provided), and one previously unconfirmed case has now been confirmed.
A total of 25 cases of confirmed or probable cases of vCJD have now
been recorded in France since 1997. The 24 confirmed cases comprise
12 femaaales and 12 males. The median age is 36 (between 19 and 58).
6 are resident in the Ile-de-France and 18 in the provinces. All the
identified cases are Met-Met homozygotes. No risk factor has been
identified. One of the 24 had made frequent visit to the United Kingdom.
--
3.US National Prion Disease Center - not updated (quarterly
statistics as of 15 May 2009)
Date: Thu 6 Aug 2009
Source: US National Prion Disease Pathology Surveillance Center [edited]
<http://www.cjdsurveillance.
Not updated since 15 May 2009: During the period 1 Jan 2009 to 15 May
2009 there were 116 referrals, of which 66 were classified as Prion
disease, comprising 37 cases of sporadic CJD, 14 of familial CJD, and
no cases of iatrogenic CJD or vCJD. (N.B. The prion disease category
includes cases where the type determination is pending, but where
vCJD has ben excluded).
4. Risk assessment
Date: Fri 17 Jul 2009
Health Protection Report Volume 3 No 28 2009 [edited]
<http://www.hpa.org.uk/hpr/
Revision to pre-surgical assessment of risk for vCJD in neurosurgery
and eye surgery units
------------------------------
Patients are routinely assessed prior to undergoing surgical or
neuro-endoscopy procedures to determine whether they may have an
increased risk of CJD infection. If this is the case, special
infection control precautions should be followed [1].
This pre-surgical assessment process has been revised to fully take
account of the latest knowledge of variant CJD (vCJD). Now patients
undergoing high risk surgery [2] or neuro-endoscopy should be
assessed to identify those who have received transfusions from 80 or
more donors since 1980. Any patients so identified have an increased
risk of vCJD, and special infection control procedures should be
followed. It is estimated that around 50 patients will be identified
in this way in the UK each year.
Hospitals are being asked to collate blood transfusion histories for
these patients, and conduct risk assessments for patients with
uncertain or incomplete transfusion histories. Patients who are found
to have an increased risk of vCJD will need to be informed via the
HPA Centre for Infections CJD section, which is coordinating the
implementation of the revised guidance, and their GP (general
practitioner; physician).
The vCJD risk to these patients is uncertain, and depends on the
prevalence of subclinical vCJD infection among blood donors, the
infectivity in the blood of infected donors, and the number of donors
the patients have received blood from.
The HPA's CfI-CJD section should be informed of any patients who are
identified prior to high risk surgery or neuro-endoscopy as having
received blood from 80 or more donors. Health Protection Units have
been asked to ensure that infection control teams are aware of the
revised guidance.
Information for healthcare workers and patients is available at:
<http://www.hpa.org.uk/
References/notes
----------------
1. Department of Health. "Assessment to be carried out before
surgery and/or endoscopy to identify patients with, or at increased
risk of, CJD or vCJD" (Annex J of ACDP TSE Working Group guidance).
2. High risk surgery is defined as surgery involving any of the
following organs or tissues (high risk tissues): brain, spinal cord,
dura mater, cranial nerves (specifically the entire optic nerve and
only the intracranial components of the other cranial nerves),
cranial nerve ganglia, posterior eye (specifically the posterior
hyaloid face, retina, retinal pigment epithelium, choroid, subretinal
fluid, optic nerve) and pituitary gland.
5.Blood transmitted vCJD
[Health Protection Agency -- Variant CJD and blood
(<http://www.hpa.org.uk/webw/
There have been 4 cases of variant-CJD infection associated with
blood transfusion: 3 of the 4 recipients developed symptoms of vCJD.
All 4 cases had received transfusions of non-leucodepleted red blood
cells between 1996 and 1999.
The 1st case of vCJD disease associated with blood transfusion was
identified in December 2003. This individual developed vCJD 6.5 years
after a transfusion of red cells. This was donated by an individual
who developed symptoms of vCJD 3.5 years after donation.
A case of vCJD 'infection' was identified a few months later in a
recipient of red cells. The donor developed symptoms of vCJD 18
months after donation. This 2nd case died from causes unrelated to
vCJD 5 years after transfusion. Post-mortem investigations found
abnormal prion protein in the spleen and a cervical lymph node, but
not in the brain, and no pathological features of vCJD were found.
The 3rd case developed symptoms of vCJD after 6 years and died 8
years and 8 months after receiving a transfusion of red blood cells.
The donor developed vCJD about 20 months after this blood was donated.
The 4th case developed symptoms of vCJD 8.5 years after receiving a
transfusion of red blood cells. The donor developed vCJD about 17
months after this blood was donated. The same donor donated the
vCJD-implicated blood transfused to the 3rd and 4th cases.
On 16 Mar 2004 the Department of Health announced that people who had
received a blood transfusion in the UK since 1980 would no longer be
able to give blood. This change was implemented on 5 Apr 2004.
6. Species barrier
Date: Mon 3 Aug 2009
Source: Science Daily [edited]
<http://www.sciencedaily.com/
People Who Eat Deer And Elk With Chronic Wasting Disease May Avoid
Infection Because Of Species Barrier, Study in Monkeys Suggests
------------------------------
Data from an ongoing multi-year study suggest that people who consume
deer and elk with chronic wasting disease (CWD) may be protected from
infection by an inability of the CWD infectious agent to spread to
people. The results to date show that 14 cynomolgus macaques exposed
orally or intracerebrally to CWD remain healthy and symptom free
after more than 6 years of observation, though the direct relevance
to people is not definitive and remains under study.
Cynomolgus macaques often are used as research models of human
disease because they are very close genetically to humans and are
susceptible to several forms of human brain-damaging disease. Thus,
it was decided to see whether exposure to CWD could induce disease in
the macaques. The study appears online in the journal Emerging
Infectious Diseases. [Journal reference: Race B et al.
Susceptibilities of nonhuman primates to chronic wasting disease.
Emerging Infectious Diseases, DOI: 10.3201/eid1509.090253,
<http://www.cdc.gov/eid/
CWD is a type of brain-damaging disease known as a transmissible
spongiform encephalopathy (TSE) or prion disease. CWD primarily
affects deer, elk, and moose. Other TSE diseases include mad cow
disease, or bovine spongiform encephalopathy (BSE) in cattle, scrapie
in sheep, and sporadic Creutzfeldt-Jakob disease (CJD) in humans.
Humans are not susceptible to sheep scrapie, but BSE appears to have
infected about 200 people, primarily in Europe in the 1990s. Those
findings provided the rationale for the present CWD-macaque study,
which began in 2003.
"We plan to continue this study for at least several more years
because, although the risk to macaques so far appears to be low, we
know that these diseases can take more than 10 years to develop,"
says Bruce Chesebro, M.D., chief of the Laboratory of Persistent
Viral Diseases at Rocky Mountain Laboratories (RML) in Hamilton,
Montana. RML is part of the National Institute of Allergy and
Infectious Diseases (NIAID) of the National Institutes of Health
(NIH). The RML group is leading the study with collaborators from the
Colorado Division of Wildlife; State University of New York Downstate
Medical Center; New York State Institute for Basic Research in
Developmental Disabilities; American Red Cross; and the University of Wyoming.
The findings by the RML group support published field studies done by
others in regions of Colorado and Wyoming where CWD is endemic.
Between 1979 and 2001, there were no significant increases in human
TSE diseases despite the likelihood that hunters in those areas were
exposed to CWD through contact with infected animal tissue and
contaminated hunting tools such as knives and saws. Extensive
laboratory data also supports a human species barrier against CWD.
Notably, the RML study also included identical testing in squirrel
monkeys, which are genetically less similar to humans than macaques.
Of 15 squirrel monkeys exposed orally to CWD, 2 displayed disease
symptoms 69 months after infection. Of 13 squirrel monkeys exposed
intracerebrally to CWD, 11 displayed symptoms between 33 and 53
months after infection. In symptomatic animals, the presence of the
CWD agent was confirmed in brain, spleen and lymph nodes.
The results in squirrel monkeys were not surprising because a study
elsewhere in 2 squirrel monkeys yielded similar results. The study by
the RML group was different, however, in that it tested oral exposure
to CWD and also studied 8 CWD samples from different areas of the
country. The results in squirrel monkeys confirmed that disease
progression in that species appears consistent with disease
progression in deer and elk, where severe weight loss is nearly always present.
"The fact that the squirrel monkeys, like the deer and elk, suffered
severe weight loss suggests that chronic wasting disease might affect
a common region of the brain in different species," notes Dr. Chesebro.
7. Scrapie prions in sheep milk
Date: Mon 3 Aug 2009
Source: Sacramento Nutrition Examiner, Examiner.com [abbreviated, edited]
<http://www.examiner.com/x-
Prion diseases found in affected sheep's milk 20 months before
animals develop symptoms
------------------------------
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/
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.
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