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Virginia Cooperative Extension Service
I W VIRGINIA VE I ERINARY NOTES ~
VIRGINIA-MARYLAND REGIONAL COLLEGE OF VETERINARY MEDICINE
September-October 1993 No.65
WHAT'S INSIDE!
PATHOGENIC ESCHERICHIA COLI: A PATHOGEN OF ANIMALS AS WELL AS
HUMANS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . Page 2
PARVOVIRUS VACCINATION
.............................................. Page 3
FISH MEDICINE SHORT COURSE . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . Page 3
FIELD SAFETY AND EFFICACY OF A COMMERCIALLY AVAILABLE LYME
DISEASE v ACCINE . . . . • . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . Page 4
ALBENDAZOLE EFFICACY AGAINST CANINE GIARDIASIS . . . . . . . . .
. . . . . . . . . . . . . . Page 4
NEW RADIOLOGY SERVICES AVAILABLE
.................................... Page 5
PRODUCER/DISTRIBUTOR TO LIMIT ANIMAL SOURCE INSULIN LINE . . . .
. . . . . . . . . . . Page 5
CONTINUING EDUCATION OPPORTUNITIES . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . Page 6
BOVINE PRACTITIONERS FALL CONFERENCE . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . Page 6
SOUTHERN FEDERATION MEETING . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . Page 6
MAILING LIST UPDATE
K~ oberts, DVM Extension Veterinarian
THOUGHT FOR THE MONTH
Page 7
Trust is the essence of all satisfying interpersonal
relationships. Trust can only be earned--without it , there is no
unity. In an environment or relationship which lacks trust , there
is a lack of unity of purpose.
Virginia II Tech IRGINIA POl.YIBOINIC INSTTlUTE
AND STA"IB UNJVERSITY
Virginia Cooperative Extension programs and employment are open
to all, r~ardless ol race, color, religion, sex, age, national
origin . handicap, or political affiliation. An equal
opportunity/affirmative
ac;tion employer. Issued in furtherance of Cooperative Extension
work, Virginia Polytechnic Institute and State University, Virginia
State University , and the U.S. Department of Agriculture
cooperating.
William A. Allen . Interim Director , Virginia Cooperative
Extension , Virginia Tech , Blacksburg; Lorenza W . Lyons. Interim
Administrator . 1890 Extension Program. Virginia State , Petersburg
. VIRGINIA ST A TE UNIVERSITY
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2
PATHOGENIC ESCHERICHIA COLI: A PATHOGEN OF ANIMALS AS WELL AS
HUMANS?
Most veterinarians know that enterotoxigenic Escherichia coli
may cause serious enteric disease, such as calf scours, in newborn
animals. These pathogenic E.coli strains produce heat-stable and
heat-labile exotoxins that cause the release of fluid into the
intestinal lumen. The heat-labile toxin is detected by Chinese
hamster ovary cell assay, and heat-stable toxin is detected by an
infant mouse model. In order to be pathogenic, these strains also
require pili or adhesion antigens to attach to and colonize the
intestine. Most clinical laboratories identify such pathogenic
strains by agglutination or other serologic tests with antisera to
the pilus antigens (eg. K88 in pigs and K99 in calves), which is
suggestive for enterotoxigenic E. coli. These strains have also
been long recognized as the cause of "traveler's diarrhea" in
humans. In addition, enteropathogenic, enteroinvasive, Shiga-like
toxin-producing, and enterohemorrhagic £.coli are also well
recognized pathogens of humans, and are identified by production of
specific toxins or toxicity in cell culture. Enteropathogenic E.
coli are important agents of infant and childhood diarrhea in
developing countries, and produce characteristic histopathologic
lesions. Many of these strains produce a toxin similar or identical
to the Shiga toxin of Shigella dvsenteriae. Enteroinvasive E.coli
strains penetrate the intestinal epithelium, producing a
Shigella-like dysentery. These strains are relatively rare.
Shiga-like toxin (verotoxin) producing E. coli produce one or both
of two antigenically distinct toxins, which are identified by
toxicity for HeLa or Vero cells in tissue culture. These isolates
cause keratoconjunctivitis in the eye of a guinea pig (Sereny
test), and are usually identified in reference labs. Each of these
pathogenic types belong to specific serotypes and can therefore be
distinguished by serotyping. Whether enteropathogenic,
enteroinvasive, and Shiga-like producers cause disease in animals
is not known, due to the difficulty in identifying these strains,
but the occurrence in animals should not be ruled out.
Enterohemorrhagic £. coli (particularly serotype 0157:H7)
produce a toxin that causes a hemorrhagic colitis, characterized by
abdominal. pain, and watery diarrhea followed by bloody diarrhea.
In young children, this strain is particularly virulent and may
cause mortality and hemolytic-uremic syndrome, characterized by
blood in the urine due to kidney infection. Several outbreaks of
enteric disease due to enterohemorrhagic E. coli have been reported
in this country. The most recent outbreak occurred in the Northwest
as a result of improperly cooked hamburger served at
Jack-in-the-box restaurants. Since 0157:H7 infections in humans are
of animal origin, one would think that infections in animals may
also occur. A paper presented at the recent American Association of
Veterinary Laboratory Diagnosticians (AAVLD) Meeting in Louisville,
KY, reported that 16 of 913 bovine herds tested had positive fecal
samples for serotype 0157:H7. It was not clear if disease was
present in the positive herds. Serotype 0157:H7 can easily be
distinguished from other E. coli serotypes by their ability to
ferment sorbitol, and can therefore be screened on MacConkey agar
containing sorbitol. Identification can be confirmed by
commercially available serologic agglutination tests. Although
serotypes other than 0157:H7 can also be enterohemorrhagic, they
are not easily identified and are not as common.
A separate paper from the AA VLD meeting reported that two E.
coli isolates from calves with fat al diarrhea were identified as
adhering and effacing strains, which are identified by attachment
to Hep-2 and other tissue cell types. These strains may cause
cellular necrosis and detachment. It is not known how common these
strains may be, but it was emphasized that the strains would have
been missed without the use of proper cell culture techniques.
In summary, it is highly likely that there are many types of ..
~ .. coli strains that can cause disease in animals. Other than
enterotoxigenic and enterohemorrhagic strains, identification of
these pathogens in most clinical laboratories is difficult or not
possible. Although there is not an established correlation between
hemolysin-producing E. coli and the pathogenic serotypes, our
laboratory screens all fecal samples on a blood agar plate for
normal flora. Normal flora is considered predominately nonhemolytic
E. coli. Occasionally, pure or predominant cultures of hemolytic E.
coli are found and a susceptibility test is done and reported on
these isolates. Clinicians should keep in mind the variety of
pathogenic£. coli strains that may exist and be significant causes
of enteric disease in both young and adult animals. -Thomas J.
Inzana, PhD, Director, Clinical Microbiology, VA-MD Regional
College of Veterinary Medicine, Blacksburg, VA.
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3
PARVOVIRUS VACCINATION
Canine parvovirus was first isolated and identified in this
country in 1978. It was the second parvovirus described in dogs and
is known as CPV-2. There is speculation that CPV-2 mutated from
another virus, possibly the feline parvovirus that causes feline
distemper.
In recent months there has been talk of the need for a new
canine parvovirus vaccine because vaccinated dogs are being
infected with the disease. Here is the most authoritative
explanation available. It comes from the highly respected Canine
Infectious Diseases Laboratory of the James A. Baker Institute for
Animal Health at Cornell University.
The apparent vaccination "breaks" are the result of certain
commercially available vaccines having lost their ability to
stimulate high enough levels of protective immunity in dogs
vaccinated with these vaccines. It is also known that there is
normal parvovirus "evolution" over time. This has been documented
at the Baker Institute where three distinct antigenic types of the
parvovirus CPV-2 have been isolated since the identification of the
original canine virus in 1978.
Another important point for owners and breeders t'o remember is
the potentially dangerous period from birth to four months of age
when maternal antibodies transferred from the bitch to the puppy
can interiere with the pup's ability to produce effective immunity
against parvovirus. So called vaccination "breaks" may occur at
this time even though the puppy has been vaccinated with an
antigenically good vaccine. The only sure protection during this
period is to protect the pups against virus exposure by means of
isolation and strict hygiene. Because of vaccination and the
prevalence of adult immunity, clinical cases of parvovirus are
limited primarily to the six weeks to six months age group.
Subclinical cases apparently occur in adult dogs rather
commonly.
Studies at the Baker Institute indicate that almost all
available vaccines produce effective immunity in healthy dogs when
properly handled. Some vaccines have had periods of inadequate
potency (and the resulting inability to effectively immunize dogs)
because of mutations in the cell lines used to produce these
vaccines.
The Baker Institute at Cornell is testing new strains of
parvovirus to see if they can develop a vaccine with an improved
ability to produce immunity in dogs against the disease.
It would seem that subtle problems in vaccine production may
account for occasional breaks in a dog's immunity against
parvovirus. Evolutionary virus mutations are difficult to detect,
predict and make adjustments for in producing effective vaccines.
New parvovirus vaccines may be available in the future and it is
comforting to know that the problem is receiving careful attention.
--Kent Roberts, DVM, Extension Veterinarian, Virginia-Maryland
Regional College of Veterinary Medicine, Blacksburg, VA.
FISH MEDICINE SHORT COURSE
A College-sponsored short course for veterinarians on clinical
fish medicine is scheduled for November 5-6 in Blacksburg. Featured
speakers are Dr. Brent Whitaker, Director of Animal Health at the
National Aquarium in Baltimore and Dr. Stephen Smith, Aquatic
Medicine, VMRCVM, Blacksburg.
Program topics include common aquarium diseases, environmental
problems affecting fish, preventative medicine programs, and case
discussions. Course participants will have the opportunity for
hands-on experience in water quality testing, anesthesia, biopsy,
and necropsy techniques. This interesting and practical course will
provide ten hours of CE credit.
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FIELD SAFETY AND EFFICACY OF A COMMERCIALLY AVAILABLE LYME
DISEASE VACCINE
A recently published study reports that vaccination of dogs with
Borrelia burgdorferi bacterin (Ft. Dodge Laboratories) is both safe
and effective. Minor reactions were observed in 38 of 1,969
vaccinated dogs (1 .9 percent). Thirty-two dogs had delayed
reactions such as fever, lethargy, soreness, signs of depression or
anorexia within 1 to 3 days of vaccination. One of these dogs
experienced reactions after the first and second vaccinations.
Another dog had one seizure. Six dogs had immediate reactions
associated with pain at the injection site. All 38 dogs having
reactions recovered within 72 hours. No immune-mediated disease was
observed in any dog after vaccination.
Protective effects of immunization were suggested by a 1.0
percent incidence (20 of 1,969) of clinical borreliosis in
vaccinated dogs compared to a 4.7 percent incidence (211 of 4,498)
in nonvaccinated dogs. Vaccination seemed to prevent disease better
in unexposed dogs than in previously exposed animals. The authors
concluded that vaccination against borreliosis is more efficacious
when dogs are young and have not been exposed to infected ticks.
··Abstracted from S.A. Levy, B.A. Lissman, and C.M. Ficke.
"Performance of a Borrelia burgdorferi Bacterin in
Borreliosis-endemic Areas." Journal of the American Veterinary
Medical Association, Vol. 202, No. 11, June 1, 1993, pp. 1834-1838,
as reported in Veterinary Quarterly Review, Vol. 9, No. 2,
April-June 1993, Texas A&M University, College Station, TX.
ALBENDAZOLE EFFICACY AGAINST CANINE GIARDIASIS
A recently published study has demonstrated that four
consecutive doses of 25 mg/kg albendazole administered orally every
12 hours was highly effective in eliminative Giardia cysts from
experimentally infected dogs. This treatment regimen removed
Giardia cysts from 5 of 5 and 18 of 20 infected dogs, while only 1
of 5 and O of 20 infected, nontreated dogs (controls) became clear
of Giardia cysts..
Results were tested with the zinc sulfate concentration
technique (ZSCT) for detecting Giardia cysts in feces . Three fecal
samples were examined within 5 days of the last albendazole
treatment (at least 24 hours elapsed between the three samples). If
one or more of the three tests demonstrated Giardia cysts, the dog
was scored positive. With the use of the ZSCT, there is a
possibility that not all positives were detected because cysts are
intermittently shed in feces. Also, conducting two tests on the
same dog makes the results only 93 percent accurate in detecting
infected dogs. Another unknown was the length of time treated dogs
remained clear of cysts. Treatment by albendazole may have only
temporarily stopped cyst production through the observation period;
cysts may have been shed again later. Because dogs also may become
reinfected after treatment, it could not be determined whether or
not albendazole only interrupted cyst production or killed
Giardia.
None of the 25 treated dogs experience side effects. The authors
stated that these results were important for several reasons:
Giardiasis is a highly prevalent and serious canine disease; it is
a zoonotic disease and drugs currently used for giardiasis
treatment have poor efficacy or severe side effects. •• Abstracted
from S.C. Barr, D.D. Bowman, R.L. Heller and H.N. Erb. "Efficacy of
albendazole against giardiasis in dogs," American Journal of
Veterinary Research, Vol. 54, No. 6, June 1993, pp. 926-928, as
reported in Veterinary Quarterly Review, Vol. 9, No. 2, April-June
1993, Texas A&M University, College Station, TX.
ANOTHER THOUGHT
You are remembered and respected for the good you do for
others.
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NEW RADIOLOGY SERVICES AVAILABLE
Computed tomography (CT) has recently been added to the
diagnostic services offered by the VMRCVM. While CT does not
replace conventional X-ray equipment, it does offer several
advantages. Computed tomography is the process of production of
cross-sectional images using X-rays and computers. The CT scan
consists of a number of continuous "slices" or images (usually 2-1
Omm in width) through a selected body part or area of interest. The
slices are made as the patient is slowly passed through the CT
gantry (where the X-rays are emitted) by a moving table. In the
gantry, the X-ray tube circles the patient and collects data from
all angles for each particular slice. A computer then collates all
the information from all the different angles and puts it together
to form a visual image of each cross-sectional slice. The biggest
advantage of CT over conventional X-ray images is that CT can image
one thin slice at a time ; there is no superimposition of overlying
or adjacent structures as there is in regular X-ray images. In
addition, CT offers enhanced radiographic contrast and object
clarity. On regular X-ray images, all organs, blood vessels, and
muscles are the same soft tissue density, and cannot be
differentiated. On CT scans, however, the different soft tissues
are easily differentiated. This is especially helpful in imaging
the brain for tumors . On conventional X-ray images, the brain is
not clearly visualized due to the overlying bony skull , and if a
mass were present, it could not be separated from other brain
density. With CT, the brain is seen clearly , without the overlying
skull. Mass lesions within the brain can often be seen, especially
with the administration of intravenous contrast. These same
advantages are present in CT scans of the spine, thorax , and
abdomen. While the skull is most commonly imaged with CT for the
detection of brain tumors, CT can also detect tumors of the spine,
as well as herniated disks. Abdominal and thoracic CT scans can
also detect tumors which are not visible on regular X-ray images.
Despite the economic considerations CT scans are more expensive
than conventional X-ray images, the diagnostic advantages of CT for
certain patients makes it an invaluable imaging modality.
The radiology section at the VMRCVM has also added new digital
fluoroscopic equipment. This equipment allows acquisition of rapid
serial images of motion studies such as esophagrams,
angiocardiograms, and portograms. Each individual image can be
enhanced or manipulated to increase diagnostic information. Using
the new laser camera, these enhanced images can then be printed
onto X-ray film for permanent storage. Digital fluoroscopy offers
several advantages over conventional fluoroscopy, including
enhanced imag9 quality and the ability to manipulate the image
after the study is complete . --Martha Moon, DVM, MS, Diplomate
ACVR, VA-MD Regional College of Veterinary Medicine, Blacksburg,
VA.
PRODUCER/DISTRIBUTOR TO LIMIT ANIMAL SOURCE INSULIN LINE
Effective September 1, 1993, Eli Lilly and Company will
discontinue production and distribution of its Ultralente lletin I
(Extended Insulin Zinc Suspension, USP, beef-pork) insulin.
The absence of this insulin will affect the procedure used by
the practicing veterinarian when treating diabetes mellitus in dogs
and cats . Reported experiences by practicing and research
veterinarians indicate that Humulin U (ultralente Human Insulin
[rDNA origin] Extension Zinc Suspension) supplied by Eli Lilly and
Company, Indianapolis, Indiana, and Ultralente (beef) supplied by
Novo Nordisk Pharmaceutical, Inc., Princeton, NJ, are acceptable,
available long-acting alternative insulins for the dog and cat.
Contact your pharmacist for the appropriate insulin diluting fluid
, if required . --As reported in Veterinary Medicine Extension
Communications, Newsletter #395-V743, July 1993, Iowa State
University, Ames, Iowa.
AND FURTHERMORE --
When negotiating, think of creative solutions for mutual
gain.
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Date
September 30
*October 1-2
*October 8-9
*November 5-6
November 11
*November 19-20
*December 10-11
*December 17-18
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VIRGINIA-MARYLAND REGIONAL COLLEGE OF VETERINARY MEDICINE
BLACKSBURG, VIRGINIA
CONTINUING EDUCATION OPPORTUNITIES FALL 1993
Sublect Location
Small Animal Medicine Update Charlottesville
Gastrointestinal Endoscopy Intermediate Course Blacksburg
Orthopedic Surgery Canine Hindlimb Blacksburg
Clinical Fish Medicine Blacksburg
Small Animal Behavior Problems Charlottesville
Practical Eye Surgery Blacksburg
Wound Management & Reconstructive Surgery Blacksburg
Small Animal Dentistry Blacksburg
*Limited enrollment course which features hands-on
experience.
Contact Hours
4
10
10
10
6
10
10
10
Note: The Clinical Hematology short course scheduled for
December 3-4 has been postponed until March 1994.
Note: Program brochures are mailed out six-eight weeks prior to
the course date. No registrations accepted until course brochures
go out. For further information, please contact: Kent Roberts, DVM,
VMRCVM - Virginia Tech, Blacksburg, VA 24061-0442, (703)
231-7181.
BOVINE PRACTITIONERS FALL CONFERENCE
The annual conference for bovine practitioners is scheduled for
October 28-29, 1993, at the Holiday Inn, Fracis Scott Key Mall,
Route 85, Frederick, MD. Starting at noon on Thursday, October 28,
with sessions on practice tips and dairy farm case studies, the
conference continues on Friday with sessions on production
management, cow comfort, environmental management, and trouble
shooting silage based rations.
Registration is $100 for both days and $60 for one day
(including meals) with half price for veterinary students and
animal health technicians. For more information, please contact:
Dr. Douglas Carmel, VMRCVM University of Maryland, College Park, MD
20742, (301) 935-6083.
SOUTHERN FEDERATION MEETING
The 76th annual convention of the Southern Veterinary Medical
Federation, Inc. will be held at the Perdido Beach Resort, Orange
Beach, Alabama, October 17-20, 1993. The program will include
sessions on clinical pathology, radiology, oncology, behavior,
marketing, and OSHA requirements. Also, speakers on dentistry,
cardiology, endocrinology, and urology are part of the varied
program. There is a separate program for technicians and support
staff. For convention information, write SVMF, P.O. Box 1695,
Cashiers, NC 28717.
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MAILING LIST UPDATE
Dear Colleagues:
In our continuing efforts at maintaining a current and accurate
mailing list for this newsletter, I request that you take a minute
to update us on any changes in address, name, practice, etc.
If you no longer wish to receive the newsletter or know of a
colleague who would like to be added to our mailing list, please
fill out and return the form below at your earliest
convenience.
We appreciate your interest in the College and the newsletter,
and welcome your constructive comments.
Sincerely,
J/hrf-IVM ~be~M, Ed~or
New Address Old Address
Please discontinue mailings ___ _
It is a great help to us if you include Virginia Veterinary
Notes when notifying people of an address change.
Please mail to: Dr. Kent Roberts
College of Veterinary Medicine Virginia Tech
Blacksburg, VA 24061 -0442
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Virginia-Maryland Regional College of Veterinary Medicine
Extension Staff:
Dr. J.M. Bowen- Extension Specialist - Equine Dr. C.T. Larsen -
Extension Specialist - Avians Dr. K.C. Roberts - Extension
Specialist - Companion Animals Dr. W. Dee Whittier - Extension
Specialist - Cattle
K.C. Roberts, Editor Maura M. Wood, Production Manager of
VIRGINIA VETERINARY NOTES
VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY
VIRGINIA COOPERATIVE EXTENSION BLACKSBURG, VIRGINIA
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