From: TSS ()
Subject: Mad cow disease could spread naturally
Date: May 26, 2006 at 7:38 am PST
Fri May 26, 2006 09:55
Mad cow disease could spread naturally
Mad cow disease and similar infections may be spread naturally in the wild when animals lick each other, according to a study by US scientists. It raised what they said was a "remote" possibility the human form of BSE could be spread by kissing.
Case-to-case transmission in humans: case reports and series in which
spread through everyday human contact is suggested
There are six reports in which this possible mode of transmission is
considered. The most recent is that of a couple from the USA who had
been married for 30 years.47
died at age 53. He had no relevant family history, but had had a rotator
cuff repair one year before disease onset. His wife developed symptoms
four and half years after her husband's death. She was morbidly obese
and had had a previous hysterectomy, hernia repair and cholecystectomy.
Both occasionally ate brains in the form of ‘kizka’, a type of sausage.
Immunocytochemistry confirmed pathogenic prion protein deposition in
brain tissue from both husband and wife. Full sequencing of the open
reading frame of the PRNP failed to demonstrate any pathogenic
mutations. Another suspected conjugal case has recently been shown not
to be CJD. The histopathological specimens did not stain for prion
protein despite the microscopic appearance of spongiform change.48
Sporadic CJD has been described in two co-workers who shared a school
wing for 9 months.49
was a 48-year-old Californian-born man of Hispanic American descent who
had had a traumatic leg amputation at age 23, but was otherwise well.
The second was a 48-year-old Chilean-born male who had a blood
transfusion 6 months before onset of symptoms, and was known to eat
lambs' brains. The first patient developed symptoms 5 months after the
last contact with his colleague and was confirmed to have spCJD 2 months
after this. The second patient developed symptoms months later and died
9 months after the last contact with his colleague.
An English woman, who died of CJD, histologically confirmed at post
mortem, was known to have contact with several affected members of a
family with familial CJD and was related to them by marriage.39
known one of the family, who later died of CJD and had afternoon tea
with her at family gatherings, twice a year, for 20 years, as well as
visiting in her final illness. The woman herself died 12 years later.
There is another similar case of probable CJD, reported in a Chilean
woman who died 13 years after contact with a family with familial CJD.
No details of contact are given. A third case of death from CJD in
someone related in marriage to a family with familial CJD has been
reported in France, in a Tunisian family. No details are given with
regards to family history or contact.21
notable about these last three incidents of supposed infection by social
contact is that all have occurred in association with familial CJD.
Although these patients were not known to have been genetically related
to their spouses, the possibility that they came from the same gene pool
cannot be dismissed.
Iatrogenic case-to-case transmission in humans: case reports and series
in which iatrogenic transmission has been proposed
It is clear that CJD can be transmitted from person to person by
injecting or implanting CJD infected instruments, tissue extracts and
points relevant to a wider understanding of the epidemiology arise. (i)
The time from inoculation to disease onset is dependent on the route of
entry, the shortest incubation being approximately 16 months, in the
case of implantation of cerebral electrodes and recipients of corneal
grafts. By contrast, the longest incubation time is 30 years following
subcutaneous and intramuscular injection of growth hormone extract and
of gonadotrophins. These incubation times call into question some of the
proposed case-to-case transmission scenarios (above). (ii) The route of
transmission predicts the clinical appearance. Those infected directly
into the central nervous system develop a global dementia, whereas those
infected peripherally develop a progressive cerebellar syndrome. The
genotype of the prion gene does not explain this difference. That the
peripheral route of infection presents as a cerebellar syndrome would
support the view that vCJD is acquired peripherally by, for example,
diet, as cerebellar signs are an early prominent feature of vCJD but not
The infectivity of blood for TSEs in animals is well described.53,
experimental scrapie, serum from infected sheep has transmitted the
disease to mice following intracerebral inoculation. Rat-to-rat
transmission has been demonstrated, also following inoculation of serum
intracerebrally. Infected mouse whole blood has been used to infect
previously healthy mice via the intracerebral route. Experimental CJD in
a guinea pig has transmitted to other guinea pigs by inoculation of
buffy coat (leukocytes and platelets) by the intracerebral,
intramuscular, intraperitoneal and subcutaneous routes, and inoculation
of infected mouse buffy coat by the intraperitoneal route has caused
disease in healthy mice.
Nevertheless, attempts to transmit CJD by infusing units of blood from
patients with CJD to the chimpanzee have failed.55
experimentally difficult, transmission of spCJD and human
growth-hormone-related iatrogenic CJD to mouse, hamster and guinea pig,
by buffy coat and whole blood, has been demonstrated on four separate
after intracerebral injection. This suggests that transmission from
human to human, via blood and blood products, is difficult but
theoretically possible. A number of case reports have suggested that
transmission by the transfusion of blood or a blood product has occurred
reported on four patients who had died of CJD in the early 1990s. None
had a history of familial CJD or had received human pituitary growth
hormone (hGH) or gonadotropin (hPG), but each had received a blood
transfusion 5 years before onset of symptoms. Unlike other reported
cases of blood-transfusion-related CJD cases, all presented with
symptoms of CJD suggestive of infection by the peripheral route—a
cerebellar syndrome in the absence of early dementia. Concern was raised
that these patients may have received blood from 1500 women who had
received pituitary gonadtrophin for infertility, three of whom have
already died of CJD ascribed to CJD-contaminated hPG. Of these three
women, two are known to have been regular blood donors.
There is only a single confirmed case of spCJD who is known to have
received albumin from a donor with confirmed CJD.57
This was a
69-year-old Canadian man who received 3 units of albumin during surgery
for a triple-coronary-artery bypass graft. The patient became
symptomatic 8 to 10 months post transfusion, and died one year later.
One case-control study has examined blood transfusion in spCJD.
identified 202 definite and probable UK cases of spCJD between 1980–4
and 1990–2. Twenty-one patients had received blood, and 29 had donated
blood. This frequency of blood transfusion or donation did not differ
from that in age- and sex-matched controls. The clinical features in
patients with a history of blood transfusion were similar to those with
a history of classical spCJD and clearly distinct from CJD in recipients
of human growth hormone. However since spCJD is a rare disease and the
number of potentially infected units of blood is small, any difference
in the rate of receipt of transfusions between cases and controls will
be small. Thus a case-control study would have to be very large to
detect such a small difference.
Dietary factors: case reports and series compatible with the dietary
route of infection
Several case reports and series have reported an apparent increase in
the prevalence of CJD in populations of people who eat sheep or wild
animal brains. There has been one case report of definite CJD in a Dutch
man who ate occasional sheep brain and an annual feast of hog brain,59
and a case
series of four patients from North America who all ate squirrel and
other animal brains, including goat.60
recent case series obtained a history of eating squirrel brains in all
five patients with probable or definite CJD seen over 3.5 years in a
neurocognitive clinic in Western Kentucky, USA.61
however, two reports of CJD in vegetarians. Matthews described a case in
a 62-year-old lifelong vegetarian.62
she had never eaten meat, meat products or offal, she had handled raw
meat, preparing food for her husband. A study of seen patients from
revealed that two cases had been vegetarians, but no further details are
Zoonotic transmission: case reports and series compatible with infection
CJD and scrapie exist together in many countries, but the incidence of
CJD in countries where there is no scrapie, such as Australia, New
Zealand and Chile, (Table 2
) is no
different from that in scrapie-endemic countries.
In France, a detailed study looking at regional distribution of CJD and
scrapie infected flocks found no relationship.64
Nevertheless as CJD is rare, the incubation period may be very long, and
both human and animal populations may be very mobile, thus any
reassurance would have to be qualified.
A recent case of an Italian man and his cat65
interest. A 60-year-old man developed CJD in November 1993 and died 3
months later. His cat developed a neurological disease at the same time,
and was killed at the time of her owner's death. Strain typing suggested
that the man was a case of sporadic CJD. The cat had the same strain,
distinct from the feline spongiform encephalopathy (FSE) strain,
described in the UK in the early 1990s.66
transmission would require that the cat had infected her owner whilst
pre-symptomatic. A common source for both cat and man would seem more
probable. The circumstances would be hard to explain without an
exogenous source of disease.
described definite or probable CJD in four patients all of whom kept
ferrets for pets. One of the cases, who had also kept ferrets 30 years
previously, had definitely been bitten by a ferret 2 years before
disease onset. After his death, the ferret was killed and examined
histologically but no spongiform change was found. In addition the brain
of the ferret was inoculated into four species of monkey and one cat,
all of whom remained well. No such studies were performed with the other
two cases of CJD in patients who, a year before diagnosis, had hip
replacements from goats as well as a case who had been a member of the
French Foreign Legion and had had sexual relations with a goat.
Occupational exposure: observations from case reports and series
Case reports and series focus on two main occupational groups; health
professionals and those who are exposed to farm animals, in particular
sheep and cattle.
There are at least 26 reports of sporadic CJD in health-care workers
include seven physicians, including a neurologist and head of an
intensive care unit, two neurosurgeons, an orthopaedic surgeon and a
pathologist, three dentists, a dental surgeon, nine nurses, three
nursing assistants and two histopathology technicians. Clinical details
are available for six of the cases.
describes a 58-year-old physician who died of definite CJD and who, 20
years previously, had frequently performed autopsies. Weber71
case in a 55-year-old orthopaedic surgeon who died of definite CJD. The
clinical picture was suggestive of a peripheral route of infection.
Twenty years previously, he had handled both sheep and human dura mater.
The specimens of dura mater were later sent to a company that sold dura
mater preparations that subsequently transmitted CJD on six occasions.
His wife did not remember any definite injury during the time he was
working with dura mater. Schoene72
case with an atypical clinical presentation including necrotizing
cutaneous lesions with vasculitis in a 54-year-old neurosurgeon, which
was later confirmed, as CJD, by experimental transmission. There was no
definite history of exposure to any case of CJD. In a case in a
he is known
to have performed over 14 000 autopsies, but it is not known if any of
them were cases of CJD. There is no information on the dentists or
nurses. One of the two histopathology technicians had been a
neuropathology technician for 22 years74
come into contact with two cases of CJD, 16 and 11 years before the
onset of her disease. The other technician75
exposed to animal and human brain.
A wide range of occupations have been reported among cases of sporadic
case series quote an excess number of farmers and farmers' wives.24,
incidence was three times the expected. An analysis of epidemiological
surveillance data in the UK from 1970–9616
statistically significant excess of cases among dairy farm workers and
their spouses and among people with greater degrees of contact with live
cattle infected with BSE. No such excess was found in abattoir workers
butchers or meat cutters.
Case control studies are the time-honoured way of studying rare
diseases. To date there have been seven case-control studies of spCJD in
Man's Sister and Wife Die of CJD Disease
By Helen Morgan, PA News
A man today described the deaths of his wife and sister from
Creutzfeldt-Jakob Disease (CJD) as a horrific coincidence.
Barry Harpers wife Phyllis, from Walham Green, Sandhurst,
Gloucestershire, died last month after battling with the sporadic form
of the brain disease for nine months.
His sister Nancy Womack died two years ago after contracting the same
form of the disease. Both women were 67 when they died. They were both
treated at the same ward in the Gloucestershire Royal Hospital.
Mrs Harpers walking was first affected before her memory started to go.
Her husband said latterly she got very angry and violent due to her
frustration at the disease.
Mr Harper, a retired fitter who is 70, said: I feel terrible. I cant
believe it. I feel completely in the dark and have no idea whatsoever
why they died.
He said he is depressed by what has happened and is having trouble sleeping.
CJD Support Network co-ordinator Gill Turner said there was one in a
million cases of this form of the disease.
She said every case of the disease is looked at by the CJD incident
panel and believed the findings of these deaths would be very interesting.
The likelihood of such close non-blood relatives getting CJD would be
very unusual, she added.
The very word sporadic means random.
According to the CJD Surveillance Unit in Edinburgh, 993 people have
died of all forms of CJD in Britain between 1990 and 2004.
Some 740 of those deaths were attributed to sporadic CJD, the most
common form of the disease.
UK- Wife And Sister Of Man Die Of Sporadic CJD
By Helen Morgan
A man today described the deaths of his wife and sister from Creutzfeldt-Jakob Disease (CJD) as a "horrific coincidence". The man's wife, from Walham Green, Sandhurst, Gloucestershire, died last month after battling the sporadic form of the brain disease for 9 months.
The man's sister died 2 years ago after contracting the same form of the disease. Both women were 67 when they died. They were both treated in the same ward in the Gloucestershire Royal Hospital. His wife's walking was first affected before her memory started to go. He said latterly she got very angry and violent due to her frustration at the disease.
Her husband, a retired fitter who is 70, said: "I feel terrible. I can't believe it. I feel completely in the dark and have no idea whatsoever why they died." CJD Support Network co-ordinator Gill Turner said there was one in a million cases of this form of the disease. She said every case of the disease is looked at by the CJD incident panel and believed the findings of these deaths would be "very interesting". "The likelihood of such close non-blood relatives getting CJD would be very unusual," she added.
According to the CJD Surveillance Unit in Edinburgh, 993 people have died of all forms of CJD in Britain between 1990 and 2004. Some 740 of those deaths were attributed to sporadic CJD, the most common form of the disease.