- Prompted by reports of neurological symptoms among workers
at 2 pork processing plants in the USA, CDC [US Centers for Disease Control
and Prevention] has dispatched an urgent bulletin to all US neurologists
requesting information about any similar cases they may come across. The
CDC sent the bulletin to American Academy of Neurology (AAN) 17 Jan 2008;
it reports that clinicians at the Mayo Clinic in Rochester, Minnesota notified
the Minnesota Department of Health in the fall of 2007 about an unusual
cluster of 12 patients who developed inflammatory neuropathy between November
2006 and November 2007.
-
- All of the subjects worked in a pork processing plant
in Austin, Minnesota, in an area of the facility where the pigs' heads
are processed. In mid-January of 2008, there were reports of an additional
cluster of patients with similar symptoms among individuals working in
a pig processing plant in Indiana.
-
- "In particular, neurologists who have diagnosed
patients with peripheral neuropathy, myelopathy, or a mixed clinical presentation
of peripheral/central (and, more specifically, myelopathic) involvement
in persons with exposure to pig butchering or processing during the past
year are asked to report this information to their state health department
and contact the CDC at (770) 488-7100."
-
- http://www.medscape.com/viewarticle/569320
-
-
- communicated by:
- ProMED-mail
- <mailto:promed@promedmail.org>promed@promedmail.org
-
- ******
- [2] CDC: letter to American Academy of Neurology (AAN)
- Date: Thu 17 Jan 2008
- Source: American Academy of Neurology (AAN) website
- http://www.aan.com/globals/axon/assets/3459.pdf
-
-
- In the fall of 2007, clinicians at the Mayo Clinic in
Rochester, Minnesota, notified the Minnesota Department of Health of an
unusual cluster of 12 patients with inflammatory neuropathy occurring between
November 2006 and November 2007 among workers at a pork processing plant
in Minnesota. An initial investigation has revealed that they all have
worked in the same area of the plant where the heads of the pig are processed.
The investigation in Minnesota is ongoing and additional patients have
been identified in Indiana, among workers in a similar plant. At this point
an etiologic agent has not been identified.
-
- These patients have frequently had illness onset with
pain, numbness, and tingling in the extremities. The illness typically
progressed with development of relatively symmetric mild to moderate weakness
involving predominantly the distal lower limbs. Occasionally, facial weakness
has also been observed. They often complain of difficulty with balance
(ataxia). Electrodiagnostic testing showed prolonged motor distal latencies
and F-wave latencies, minimal sensory nerve conduction abnormality, and
evidence of mild denervation of distal muscles on EMG (electromyography).
-
- Of the cases in which cerebrospinal fluid (CSF) has been
obtained, all have had elevated CSF protein, with minimal if any pleocytosis
(such as, cytoalbuminologic dissociation). Thoracic and lumbar magnetic
resonance imaging has demonstrated mildly thickened nerve roots and contrast
enhancement. Time of illness progression ranged from several days to months
with severity of illness ranging from mild weakness in most cases to paraplegia
in one. Most have had some level of recovery.
-
- Given the apparent close association of these patients
with participation in the processing of pig head material, it is possible
that similar illnesses are occurring at other pork processing plants. The
CDC is requesting neurologists to provide information about patients who
may have developed illnesses similar to that reported by the Mayo Clinic.
In particular, neurologists who have diagnosed patients with peripheral
neuropathy, myelopathy, or a mixed clinical presentation of peripheral/central
(and, more specifically, myelopathic) involvement in persons with exposure
to pig butchering or processing during the past year are asked to report
this information to their state health department, and contact the CDC
at 770-488-7100.
- --
- communicated by:
- ProMED-mail
- <mailto:promed@promedmail.org>promed@promedmail.org
-
- More clinical information is given here but the issues
of using air pressure to extract the porcine brain in the plants where
cases occurred is not mentioned and what kind of personal protective equipment
was used is also not stated. - Mod.LL
-
- *****
-
- [3] Neurology Today: upcoming article [7 Feb 2008]
- Date: Mon 28 Jan 2008
- Source: American Academy of Neurology (AAN) website
- http://www.aan.com/globals/axon/assets/3462.pdf
-
-
- An unusual illness in a dozen workers at a Minnesota
pork processing plant has state health officials concerned that the cluster
could be an unknown animal-borne nervous system disease.
-
- All of the employees worked in an area where compressed
air was used to cleanse brain cavities, giving rise to speculation that
the illness, health officials are calling it an unknown inflammatory polyneuropathy,
may have been caused by exposure to an infectious agent in airborne brain
particulate matter.
-
- Early reports suggested chronic inflammatory demyelinating
polyneuropathy (CIDP), which damages the myelin sheath surrounding nerves
and typically progresses for months. However, CIDP, as a specific diagnosis,
was ruled out after workers were examined by neurologists and had nerve
conduction studies.
-
- According to Daniel Lachance MD, the Mayo Clinic neurologist
who is caring for many of the workers, "an astute nurse" at the
plant brought the symptoms to the attention of local Austin physicians,
who in turn notified the Mayo Clinic. Dr Lachance recognized the symptoms
as being unusual. He told Neurology Today in a telephone interview that
while the illness shares many similarities with CIDP, tests have shown
it has a different signature. Unlike CIDP, which is characterized by slowing
or blocking of nerve conduction, the workers' illness can be categorized
only as an inflammatory response that is attacking nerve roots proximally,
and peripheral motor nerves distally, he explained.
-
- "While they do have electrophysiological evidence
for peripheral nerve involvement and the disorder appears associated with
a remarkable activation of the immune system, the clinical picture is different
from CIDP," he said...."the syndrome is best characterized as
an inflammatory polyradiculopathy."
-
- "All of the information we have to date indicates
that the general public is not at increased risk for developing this type
of illness," said Minnesota commissioner of health Sanne Magnan MD
PhD, in a news release. "Also, there is no evidence that the foot
supply has been affected."
-
- Symptoms appeared over several weeks to months, characterized
by muscle weakness, paresthesias, especially in the legs, and chronic fatigue
with a sudden onset. In most patients, symptoms have been severe enough
to limit many daily activities, according to Dr Lachance, noting, for example,
that many have difficulty managing stairs. Symptoms were first noted in
a worker in a local soccer league when he could not continue playing. In
some patients, sensory symptoms and discomfort in the neck, lower back,
and limbs dominate the clinical picture, while in others, mild to moderate
weakness can be demonstrated on the neurological examination. Treatment
has generally consisted of observation in milder cases, while the more
severely affected have been treatment with steroids or intravenous immunoglobulins.
-
- At press time, the Minnesota state health department
had not identified a cause of the illnesses. Investigators had interviewed
all 12 patients, as well as workers who worked in the same area and those
who did not, collecting information on work history, medical history, potential
exposures, and other topics. Clinical specimens, including throat swabs
and blood, were obtained from 90 per cent of those interviewed and evaluation
for possible infectious agents is ongoing.
-
- All cases of the cases involved people who worked in
an area where swine heads are processed and brains removed. A compressed
air system for cleaning out the brain cavities of processed swine was introduced
at the plant shortly before the 1st worker complained of symptoms, and
there has been concern that the illness might have been caused by inhalation
of aerosolized brain tissue or a microorganism associated with this mode
of exposure.
-
- The plant quickly stopped using the compressed air system
and implemented other measures to protect workers in early December 2007,
and as of press time, no new cases with symptom onset since the changes
were made have been reported, according to Dr Lachance.
-
- Aerosolized blood and organ particulate in slaughterhouses
and meat processing plants, referred to as "blood mist" in occupational
safety circles, has long been recognized as a potential health risk and
there are regulations for worker exposure in the Occupational Health Act.
Even so, the symptoms do not match any known neurological illness that
can be transmitted from animals to humans.
-
- Exposure to chemical toxins at the plant has been ruled
out as a cause. To date, no similar cases have been found in other states
[as noted earlier in the posting, there appears to be cases in an Indiana
plant using the same compressed air technique - Mod.LL] or elsewhere in
Minnesota.
-
- Because the workers were close to the brain removal area,
concern was raised that the pig CNS might be the infectious vehicle. "But
we did not know of any specific infectious or autoimmune disorder like
this that is caused by exposure to animal tissue," Dr Lachance said,
adding the disorder could be an autoimmune response to an infection. "Transverse
myelitis or a brachial plexopathy after a viral syndrome, Guillian-Barre
syndrome associated with _Campylobacter_ infection are the most likely
models, but to our knowledge, nothing like this has even been encountered
before."
-
- Byline: Kurt Samson
-
- --
- communicated by:
- ProMED-mail
- <mailto:promed@promedmail.org>promed@promedmail.org
-
- This piece states, of note, that the use of the compressed
air technique was started only shortly before cases began. The cause here
may or may not be an infectious agent but could be an immunologically reactive
moiety such as myelin.
-
- More information is clearly needed here to better define
this entity. - Mod.LL
-
- In a telephone call the MN epidemiologist reported that
there is no respiratory protection although full face shields are in use.-
Mod.TG 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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