- A ProMED-mail post ProMED-mail is a program of the International
Society for Infectious Diseases
-
- [1] Date: Tue 29 Jun 2004
- From: ProMED-mail
- Source: News-medical.net, 29 Jun 2004 [edited]
-
-
- Unexplained neurological illness in cattle and sheep
- assessing the potential risks to human health
- ----------------------------------------------------
- Following a recent announcement by the Department of
the Environment Food and Rural Affairs (DEFRA) concerning cattle and sheep
with an undiagnosed encephalitic illness, the Health Protection Agency
were tasked with convening a group of experts to assess the potential risk
to human health.
-
- At the meeting, which was held on 21 Jun 2004, experts
reviewed information about the original case in a heifer, another unrelated
case in a bull, and 20 cases in sheep which had occurred over a 10 year
period. They were also informed of a further 7 adult cattle submitted under
BSE Orders between 2000 and 2003. Recent laboratory investigations from
the original case in a heifer identified an enterovirus as the most likely
cause of infection, which is unlikely to pose a threat to human health.
Samples from the other cases will now also be tested for enteroviruses.
-
- Dr Dilys Morgan, who led the group on behalf of the Agency,
said; "It is reassuring that the cause of illness in the heifer has
been identified. Enteroviruses are a common cause of illness in both animals
and humans, however they do not usually cross between species. This combined
with the fact that animals are examined prior to slaughter by a veterinary
surgeon and any with symptoms of acute viral disease are prevented from
entering the food chain, and that enteroviruses are killed by heat, means
that this case is thought unlikely to pose any risk to human health".
-
- In considering the available data on all the cases, the
group of experts agreed that for a variety of reasons they also didn't
pose a significant risk to human health. These reasons included the fact
that there was no increasing trend in the low number of samples being submitted
for testing from cows and sheep with neurological illness over the last
10 years, and that no apparent link has been identified between these cases
and the cases represented a variety of clinical and pathological findings.
-
- Dr Morgan concluded, "As more evidence becomes available
we will continue to assess the risk, but the information we have so far
suggests that these cases are unlikely to pose a significant risk to human
health."
-
- ******
-
- [2] Date: Tue 29 Jun 2004 From: Tom Barrett (IAH-P)
-
- The recent case of what is described as a type of cattle
poliomyelitis in a young cow in Britain is reminiscent of similar cases
reported in the 1970s in the USA and in Germany. In 1995 a paper (1) by
a German group described the isolation of a viral agent from brain explants
of a 15 month old heifer with clinical signs of sporadic encephalomyelitis.
The nucleocapsid structures were reminiscent of those of paramyxoviruses,
and positive fluorescence reactions were obtained with sera obtained from
sub-acute sclerosing panencephalitis (SSPE) patients and with rabbit hyperimmune
anti-rinderpest virus antiserum.
-
- In 1979 a similar paper was published detailing a case
from the USA(2). The virus was found in an animal experimentally infected
with malignant catarrhal fever virus. Again in indirect fluorescence tests,
the agent reacted with both measles and rinderpest virus antisera, and
the authors stated that this was the 1st report of a morbillivirus isolation
from North American cattle.
-
- In 1994, during the course of a project to complete the
sequence of the rinderpest virus genome (3), we found very major differences
in the sequence of the matrix (M) protein gene derived from our virus isolate
from that which had been published by an American group (4). The difference
in isolates was that Limo & Yilma had sequenced the purported wild
type virus and we had sequenced the vaccine strain derived from this virus.
Curiously all the other genes of the 2 viruses showed >97 per cent identity.
We independently sequenced the wild type strain derived from a different
source and found it to be almost identical to our vaccine strain sequence.
The conclusion we came to was that the American sequence was derived from
a contaminating virus present in the primary bovine cells used to culture
the virus for sequencing, which was most likely related to the unknown
morbillivirus-like viruses found in the previous bovine cases. In addition,
it was noted that one of the unvaccinated control animals used in a vaccine
trial to test vaccinia recombinant viruses at the Plum Island laboratory
in New York (5), had cross-neutralizing antibodies to rinderpest virus
prior to challenge, indicating exposure to another morbillivirus. The animal
was not protected from rinderpest, however. A similar virus could be the
causative agent of the current meningoencephalitis case.
-
- References 1. Bachmann, et al. Sporadic bovine-meningo-encephalitis
- isolation of a paramyxovirus. Arch Virol 1995; 48: 107-20. 2. Coulter
& Storz. Identification of a cell-associated morbillivirus from cattle
affected with malignant catarrhal fever: antigenic differentiation and
cytologic characterisation. Am J Vet Res 1979; 40: 1671-7. 3. Baron, et
al. Cloning and sequence analysis of the matrix (M) protein gene of rinderpest
virus and evidence for another bovine morbillivirus. Virology 1994; 200:
121-9. 4. Limo & Yilma. Molecular cloning of the rinderpest virus matrix
protein gene:Comparative sequence analysis with other paramyxoviruses.
Virology 1990; 175: 323-7. 5. Giaredoni, et al. A vaccinia virus double
recombinant expressing the F and H genes of rinderpest protects cattle
against rinderpest and causes no pock lesions. Proc Natl Acad Sci USA 1991;
88: 8011-5.
-
- -- Tom Barrett, Institute for Animal Health, Pirbright
Laboratory, UK email:
-
- -- ProMED-mail
-
- [The DEFRA announcement, and Dr Barrett's comment, taken
together, suggest that the identity of the causative agent remains uncertain,
and it cannot be assumed that the same agent is responsible for these rare
cases of poliomyelitis-like illness in cattle and sheep.
-
- Enteroviruses are ubiquitous small RNA viruses that multiply
in the gastrointestinal tract of humans and animals but can also multiply
in other tissues, including neural tissue. In humans, clinical manifestations
include mild meningitis, encephalitis, myelitis, myocarditis, and conjunctivitis.
However, infection may frequently be asymptomatic: currently, more than
30 different human echoviruses are recognized that have no association
with any known disease. Less is known about the diversity of animal enteroviruses,
the foot and mouth disease viruses apart. Consequently, the detection of
an uncharacterized enterovirus in a single case is difficult to evaluate
in the absence of other corroborating evidence.
-
- Tom Barrett has drawn together some disparate observations,
well-supported by experimental data, which suggest that a previously unsuspected
morbillivirus-like paramyxovirus may be prevalent in some domestic animals.
The morbilliviruses -- which include the distemper viruses of carnivores,
rinderpest of bovines, and the human measles viruses -- are all associated
with neurological disease. The final diagnosis is still some way off. On
the other hand, DEFRA's interim conclusion, that these cases are unlikely
to pose a significant risk to human health, seems reasonable on the basis
of the information available so far. - Mod.CP]
-
- _____
-
- Hello, Jeff - I need more time to thoroughly analyze
the information given in the Promed post. First of all, I still question
why, and how is the "white" matter of the brain affected. The
Promed post has not sufficiently answered that question. The swift destruction
of the white matter indicates something else going on.
-
- I would also like more information on the background
of the cattle. Were they recently vaccinated? Are they pastured near a
lab? etc etc.
-
- Were the cattle part of some new vaccination trial?
-
- Quite possibly, we have another vaccine trial or lab
involvement. ...or something more sinister. If the US has upgrades its
labs to re-enter the bioweapons business (defensively...of course) it
is quite possible that the UK is doing the same.
-
- Developing human and livestock illnesses, recombinations
of illnesses etc in attempt to find vaccines, etc could really lead to
some of the vialest bioweapons on the face of the earth. Plum Island was
opened in 1954 with a mandate to find efficient ways of "taking out"
soviet livestock. Not much change since 54, only the face of the enemy.
-
- Obvioulsy this new bovine "polio" is an efficient
and speedy killer of cattle.
-
- Patricia A. Doyle, PhD Please visit my "Emerging
Diseases" message board at: http://www.clickitnews.com/ubbthreads/postlist.php?
Cat=&Board=emergingdiseases Zhan le Devlesa tai sastimasa
- Go with God and in Good Health
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