NEWSLETTER
Issue 43 November 1999
Archives
Contents
Vampires
and Rabies
Did Count Dracula
need a rabies vaccination rather than a stake through the heart.
In many parts of the world
the vampire bat is a source of rabies infection. In Europe the connection
between vampires and rabies has more to do with Count Dracula than bats.
A Spanish scientist has claimed
that the legends of vampires may have originated from the bizarre behaviour
of men infected with rabies virus.
The symptoms of rabies match
many of the attributes ascribed to vampires. Stories of vampires became
common in eastern Europe in the early eighteenth century, a time when rabies
was sweeping through the region.
Vampires are said to roam
at night, sometimes appearing in the form of a dog, wolf or bat. They attack
people and animals and often drink their victims blood. They are reputed
to shun light and mirrors and have an insatiable sexual appetite.
Juan Gomez-Alonso (Neurology
vol 51, p 856) says that shortly after seeing a film about vampires he
read an article about rabies. He was shocked by the similarity between
the behaviour of vampires and rabies victims. He felt the similarities
are too similar to be coincidental.
In severe cases of rabies
the victims can become violent and animal-like. In particular, muscle spasms
in the face and neck can give the victim the look of an angry dog. During
these attacks the victim cannot swallow and sometimes vomits blood. Exposure
to bright light or specular reflections from water or mirrors may trigger
the spasms. There may be an overwhelming impulse to attack and bite people.
Men with the disease may engage in extensive sexual activity and may have
a painful erection that lasts for days.
There is evidence to suggest
that between 1721 and 1728 in Hungary there was a massive epidemic of rabies,
roughly the time and place that many of the vampire legends became established.
The presence of animals and
people exhibiting the same symptoms would explain the stories of vampires
changing their form and the legend that once bitten by a vampire you become
one as well.
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Veterinary
Nursing - BASICS
What
are bacteria?
Bacteria are classified as
prokaryotes, cells that lack internal membranes. They contain their own
genetic material deoxyribonucleic acid (DNA) which is not contained in
a nucleus like other cells. Additional genetic material may be present
in the form of plasmids.
Bacteria may take on a variety
of shapes and forms. The most common are cocci, (spheroid), bacillus (rod
shaped), filamentous (thread like), spirilla (corkscrew shaped), vibrio
(comma shaped). There are a wide variety of variations on these shapes
and some bacteria can exist in more than one form, pleomorphism. They may
have additional exterior features such as flagella, one or more filamentous
appendages which enables a bacteria to propel itself along. Protrusions
of the cell membrane, pili enable bacteria to attach themselves to other
cells.
Reproduction
Bacteria reproduce by a
process of binary fission. First the bacteria makes a copy of its DNA (mitosis)
and then divides into two identical cells. Bacteria can live and multiply
in a variety of environments. From the high temperatures of a thermal spring
to the low temperatures of a refrigerator. Disease causing organisms usually
have an optimum growth temperature close to normal body temperature. When
grown in the laboratory situation the growth temperature requirements of
a bacteria can be used as a distinguishing feature.
Atmosphere
Organisms can also be classified
by their atmospheric requirements. Aerobes require oxygen, anaerobes die
in the presence of oxygen, facultative anaerobes can grow with or without
oxygen, microaerophilic organisms require a reduced oxygen environment.
Nutrition
Although bacteria can synthesise
and metabolise a wide variety of food sources from sunlight (photosynthesis)
to sugars (fermentation) their nutritional requirements can be very precise.
This property is used in the laboratory to isolate bacteria from mixed
cultures. For example Salmonella can be isolated from other enteric organisms
such as E.coli by adding selenium to the culture medium. Even a small change
to the pH (acidity or alkalinity) of a growth medium can encourage or discourage
growth. This feature is used to isolate yeasts which can usually withstand
an acid (low pH) environment.
History
It is believed that the
17th century Dutch naturalist Antoni van Leeuwenhoek first recognised bacteria
when he was developing the first microscope. It was Frenchman Louis Pasteur
and the German Robert Koch who showed that bacteria were associated with
disease.
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Clin
Path Club
First
Meeting Hailed a Success
Introduction
The first meeting of the
NWL Clin Path Club took place on Thursday 14th October at North Western
Laboratories. The meeting was attended by 21 Veterinary Surgeons from as
far away as Rochdale and the Wirral. This was despite a clash with a LVA
meeting. Apologies were received from 9 others. Alistair Parker opened
the meeting and welcomed all those present . He outlined the objectives
behind the meeting. NWL wanted to provide a opportunity for those Veterinary
Surgeons with an interest in any aspect of pathology to meet with colleagues
with a similar interest. To provide the opportunity to discuss cases, exchange
ideas and information and call upon the expertise of the NWL pathologists.
There would also be seminars and workshops presented by experts.
FNA's Are they worth
the effort ?
Jane Miller gave a short
illustrated talk entitled " FNA's are they worth the effort". She demonstrated
a variety of methods for taking and preparing samples for examination and
illustrated examples of good and bad sampling and preparation technique.
Clinical Case Book
Three clinical case presentations
were made members of the audience. One from Austin Kirwan from Ormskirk
and two from Stuart Ellis from Preston.
Case 1
Austin Kirwan from Ormskirk
presented an interesting case of a coagulopathy in an adult female GSD.
The animal was presented with a haematoma and petechiation of the mucus
membranes. The animal had an extended bleeding time, one step prothrombin
time and activated partial thromboplastin time. As there was response to
vitamin K initially the problem was thought to relate to a rodenticide
toxicosis. However the coagulopathy persisted and further biochemical tests
indicated end stage liver disease. Unfortunately due to cost restrictions
no further investigations were undertaken.
Case 2
Stuart Ellis from Preston
presented two cases. The first involved a lymphadenopathy in a 11 year
old female Doberman. The case served to demonstrate the value of a simple
haematological and biochemical work up as an initial approach to investigation.
Because the principle presenting sign was a lymphadenopathy Stuart confessed
that he had decided to go for a FNA. This unfortunately revealed little
of diagnostic value only reactive changes being reported. Subsequent haematology
however revealed a very high white cell count with lymphocyte morphology
which allowed the pathologist to provide a categorical diagnosis of a chronic
lymphocytic leukaemia, which of course does not produce neoplastic changes
in the lymph nodes. The patient was placed on chemotherapy and has responded
well.
Case 3
Stuart's second case involved
a 4yr old British Blue male cat with hind limb weakness bladder stasis/incontinence
and a bite wound at the base of the tail.. General examination revealed
an enlarged L kidney, which was confirmed by radiography. Routine biochemistry
and haematology had proved unremarkable. The patient was FeLV and FIV negative.
Microbiological examination of the wound recovered an atypical Actinomyces.
This organism has the characteristic of forming walled off granulomatous
lesions. Although there was some response to initial antibiotic therapy
the problem proved poorly responsive to treatment with a variety of antibiotics.
One of the principle mysteries was the failure to identify any reason for
the hind limb weakness. This aspect of the case generated considerable
discussion. A recommendation for euthanasia on humane grounds was not accepted
by the owners and the patient was taken to another practice. The outcome
is unknown. All three presentations generated a lively and informed discussion.
The meeting ended with an open discussion.
Next Meeting
There was a general agreement
that the evening had been a success and that it should be repeated. Those
present had welcomed the opportunity to meet with colleagues for a professional
and social exchange. The next meeting will be on Thursday 13th January
2000. Details will be circulated. Watch this space for further information
or visit the web site at www.nwlabs.co.uk .
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Bats
in the Boot Room
The rare Daubenton's bat
delays plans to demolish and rebuild Wembley stadium, the home of English
soccer.
Bat experts from English
Nature are investigating reports that bats are roosting in or near the
site. Daubenton's bat is more likely to roost in newer buildings, such
as Wembley, unlike its common cousin the Pipistrelle, which prefers church
belfries and such.
Only fourteen bat species
remain in Britain after the Mouse-Eared bat disappeared in 1990.
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Tail
End
Cough it up!
A letter in the Veterinary
Record a couple of years ago by R.G. Allpress recalled some of the surprising
objects that have been retrieved from dead animals.
In 1881 a horse which had
suffered for some time with persistent respiratory problems eventually
ended up in the "Knackers". It was found to have a toad at the bottom of
its trachea. The toad was apparently still alive and had changed its colour
to blend in with its new environment.
Was this, Allpress wondered
the origin of the expression "a frog in the throat".
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