ISRAEL JOURNAL OF
VETERINARY MEDICINE
Vol. 57 (2) 2002
ABSTRACTS OF PAPERS
PRESENTED AT THE 26th ANNUAL
ISRAEL VETERINARY
SYMPOSIUM, MARCH 26, 2002
Symposium chairperson: K. Perk
Honorary director, Koret School of Veterinary Medicine
DIROFILARIA REPENS - A ZOONOTIC AND ENDEMIC DISEASE
AGENT IN ISRAEL
G. Baneth1, Y. Anug2, Z. Volansky3, G. Favia4 and S. Harrus1
1. Koret School of Veterinary Medicine, Hebrew University, Rehovot
2. Pathovet laboratories, Kfar Bilu
3. Nahariya clinic for companion animals, Nahariya
4. University of Camerino, Camerino, Italy
Zoonotic filariasis caused by Dirofilaria repens is prevalent in several regions of the world,
including southern Europe, Africa and southern Asia. Due to the recent rise in the number of
human infections in Spain and Italy, it is considered an emerging zoonoses in these countries.
Dogs, foxes and cats are the reservoir for this infection and people are accidental “dead end”
hosts in which the life cycle is not completed. The mosquito vector of D. repens include
species belonging to the genera Culex and Aedes. Human dirofilariasis was first reported in
Israel by Romano (1976) and has since been sporadically detected with an increased
frequency since 1995.
During 1998 to 2001, eight cases of canine dirofilariasis with D. repens were diagnosed in
dogs at the Hebrew University veterinary teaching hospital or at a veterinary diagnostic
laboratory. The geographic locations from which canine D. repens were detected were
compared to the locations from which human infections with this filaria were reported in Israel
since 1995. All 6 human patients and the majority of the canine cases (6/8) were from the
north of Israel. The two dogs from central Israel had a history of living previously in the north
of the country, until 1-2 years prior to the diagnosis. The region of the northwestern Galil
appears to be the most severely infected, with most cases diagnosed in the vicinity of
Nahariya and Acre.
In conclusion, human and canine dirofilariasis caused by D. repens appears to be endemic
in the Galil region of Israel. Further research is warranted to shed light on the epidemiology of
this infection and to detect the identity of the mosquito vector of D. repens infection in Israel.
DETECTION OF SHEEP-ASSOCIATED MALIGNANT
CATARRHAL
FEVER (SA-MCF) FROM INFECTED CATTLE USING
HEMINESTED PCR
D. David1, J. Brenner2, O. Fridgut2 and S. Perl3
1. Rabies Laboratory, 2. Department of Virology, and 3. Department of Pathology,
Kimron Veterinary Institute, 50250 Bet Dagan, Israel.
An unusual MCF outbreak occurred in a feedlot family farm in Israel. Thirty-four calves out of
100 died over a period of 4 months. Malignant catarrhal fever (MCF) disease was suspected
based on the clinical signs, pathological and histopathological findings. The MCF is a fatal
disease of domestic cattle and a variety of other species of ruminants. There are at least two
gammaherpesviruses responsible for the etiology of MCF. A) The alcelaphine herpes virus-1
(AlHV-1), wildebeest associated MCF in Africa and B) The ovine Herpes virus-2 (OvHV-2). A)
The AlHV-1 wildebeest represents the natural asymptomatic host which transmits the virus in
susceptible ruminants. B) OvHV-2 is the cause of SA-MCF in most regions of the world where
cattle and bison are infected by contact with sheep.
We used the heminested PCR method to detect SA-MCF virus in brain tissue of two dead
calves. The nucleotide sequence analysis revealed a 100% similarity between the
heminested PCR product and the OvHV-2 sequence, and only a 68.8% similarity with
AlHV-1.
In summary: The heminested PCR method was found useful for the diagnosis of SA-MCF in
infected cattle and for epidemiological studies of OvHV-2 in sheep.
RECOMBINANT MAMMALIAN GROWTH HORMONES AND
THEIR PHYSIOLOGICAL EFFECTS
A. Levanon
Bio-Technology General (Israel) Ltd., Kiryat Weizmann, 76326 Rehovot, Israel
The use of molecular biology methods in combination with genetic engineering technologies
facilitated the production of large quantities of highly purified recombinant proteins, such as
hormones. The availability of sufficient amounts of authentic recombinant mammalian growth
hormones with biochemical structure identical to that of natural pituitary-derived growth
hormone enabled the performance of various comparative studies in which recombinant
growth hormones were administered to different animal species. Studies were focused on
their function, tissue distribution and physiological effects following long-term administration.
The effects of bovine, porcine, sheep, chicken and carp growth hormones will be discussed
as well as issues related to benefits versus risks in milk and meat production.
EVALUATION OF NON-INVASIVE SAMPLING TECHNIQUES FOR THE DIAGNOSIS OF
CANINE VISCERAL LEISHMANIASIS USING ITS-1 PCR
D. Strauss-Ayali1, A. Naseredeen2, C. L. Jaffe2, O. Burstein2, G. Schonian3 and G. Baneth1
1. Koret School of Veterinary Medicine, P. O. Box 12, 76100 Rehovot.
2. Department of Parasitology, Hadassa School of Medicine, Hebrew University, Jerusalem.
3. Institute for Microbiology and Hygiene, Humbold University, Berlin.
Zoonotic visceral leishmaniasis (VL) caused by Leishmania infantum has been reported
recently in central Israel and in the Galilee region of north Israel. Serology and culture of
spleen and lymph node aspirates has been used as gold standards. The aim of this study was
to evaluate a polymerase chain reaction (PCR) method for the identification of Leishmania
DNA as a non-invasive diagnostic method. Specimens obtained from dogs with positive
Leishmania serology included: conjunctival swabs, skin scrapes and spots of blood and
spleen and lymph node aspirates on filter paper. These were subjected to phenol-chloroform
DNA extraction. The internal transcribed region 1 of L. infantum ribosomal operon sequence
(ITS-1, Accession No. AJ000289) was used as a template for the amplification of a 314bp
fragment. DNA samples obtained invasively from the spleen and lymph node of 7 seropositive
dogs correlated positively with parasite cultures (6/7 positive spleen samples and 5/5 positive
lymph node samples by PCR vs. 5/7 positive by culture). Using the non-invasive samples, the
conjunctival swabs were superior to splenic culture and PCR (7/7), while apparently healthy
skin and blood showed a lower rate of positivity by PCR (4/7 and 1/7, respectively). Only 50%
(2/4) of the skin scraping from dermal lesions were positive for Leishmania DNA.
The results indicate that PCR of conjunctival swabs obtained non-invasively has a similar
degree of sensitivity to PCR of splenic and lymph node aspirates and to culture of splenic
tissue obtained by invasive procedures. The sensitivity of conjunctival PCR was identical to
that of serology. More samples will be evaluated to assess the benefit of using ITS-1 PCR of
DNA obtained from conjunctival swabs for epidemiological studies.
AN ELISA FOR HEPATOZOON CANIS ANTIBODIES
L. Gonen1, D. Strauss-Ayali1, V. Shkap2 and G. Baneth1
1. Koret School of Veterinary Medicine, Hebrew University, Rehovot.
2. Department of Parasitology, Kimron Veterinary Institute, Bet Dagan.
Hepatozoon canis is a tick-borne protozoal parasite, classified in the phylum Apicomlexa and
family Haemogregarinidae. H. canis is distributed world wide and its mammalian hosts are
wild and domesticated dogs. Clinical signs in H. canis infected dogs range from an
asymptomatic infection to a severe life threatening disease with fever, lethargy and
emaciation.
H. canis antigen was purified from the blood of a naturally infected dog. Infected blood
collected from the dog was used to obtain the buffy coat layer. Leukocytes were disrupted by
nitrogen cavitation and cell-free gamonts were collected by centrifugation, washed in PBS
and sonicated. The resultant nitrogen phase was used for coating plates at 100 ng
protein/well. The examined sera were analyzed for the presence of anti-H. canis IgG at 1:100
dilution and the plate was read at 405 nm. Possible cross-reactivity with other parasites was
investigated by testing sera from dogs naturally or experimentally infected with several other
canine pathogens.
The kinetics of antibody formation was examined in sera from 12 experimentally infected
dogs. A significant elevation in the serologic titer (3 to 10 fold) occurred between 7 and 20
days post infection. The maximal antibody titers were obtained between 35 and 40 days post
infection, and the antibody titers remained elevated until the end of the experiment, 4 months
post infection. ELISA was used for screening the antibody titer for H. canis in sera from dogs
that were found either positive or negative for H. canis parasitemia. Seventy seven sera were
examined and of 36 parasitemic dogs, 28 (78%) were seropositive. Of 29 aparasitemic dogs,
none was seropositive. No cross reactivity was detected with sera from dogs infected with
Leishmania infantum, Toxoplasma gondii, Neospora caninum, Babesia canis, Ehrlichia canis,
Dirofilaria repens and Spirocerca lupi.
These results indicate that ELISA has a good sensitivity (78%) and excellent specificity
(100%) for the detection of H. canis in dogs, as compared to the detection of gamonts.
BABESIOSIS IN A CAT FROM ISRAEL - A CASE REPORT
G. Baneth1, M. J. Kenny2, S. Tasker2, Y. Anug3, V. Shkap4, A. Levi5 and S. E. Shaw2
1. Koret School of Veterinary Medicine, Hebrew University, Rehovot. Israel.
2. Acarus Unit, School of Veterinary Medicine, University of Bristol, Bristol, UK.
3. Pathovet laboratory, Kfar Bilu, Israel.
4. Kimron Veterinary Institute, Bet Dagan, Israel.
5. Mevasseret Veterinary Clinic, Mevasseret Zion, Israel.
Naturally occurring babesiosis in domestic cats has been reported mostly from South Africa
where the infection is caused by Babesia felis, a small Babesia that causes anemia and
icterus. Sporadic cases of Babesia spp. Infection in domestic cats have been reported from
several countries including France, Germany, Thailand and Zimbabwe.
Large Babesia piroplasms were detected on blood smears from a domestic cat living in
central Israel. The cat had a history of exposure to ticks and was admitted with complains of
acute lethargy and anorexia, fever (400C), anemia, icterus and a parasitaemia of 2%. The cat
recovered clinically following an intramuscular injection of 2.5 mg/kg imidocarb dipropionate
and 10 mg/kg/day of doxycycline orally for 21 days. It tested positive for feline
immunodeficiency virus (FIV) antibodies and for ‘Candidatus Mycoplasma haemominutum’
(basonym Haemobartonella felis) by real time PCR. PCR of blood using Babesia specific
primers for the 18S rRNA gene were positive. Sequencing of a 623 basepair segment of the
18S rRNA gene from the cat showed 99.4% identity with Babesia canis. Sequencing of a
protein of the internal transcribed spacer region (ITS) which allows sub-speciation of B. canis,
showed only 70% identity with B. canis rossi, and a lower identity with other B. canis subspecies. Genetic characterization of the feline Babesia isolates is ongoing.
This cat represent the first case of feline babesiosis reported in Israel. The infection was
associated with fever, anemia and icterus. Genetic characterization of the isolates indicated
that it might be closely related to B. canis.
PSAMMOMYS OBESUS AND THE ALBINO RAT — TWO DIFFERENT
MODELS OF NUTRITIONAL INSULIN RESISTANCE, REPRESENTING
TWO DIFFERENT TYPES OF HUMAN POPULATIONS
R. Kalman, Hebrew University of Jerusalem
Animal models for insulin resistance and type 2 diabetes are required for the study of the
mechanism of these phenomena and for better understanding of diabetes complications in
human populations. Type 2 diabetes is a syndrome affecting 5-10% of the adult population.
Hyperinsulinemia, hyperglyceridemia, decreased high-density lipoprotein (HDL) cholesterol
levels, obesity and hypertension, all form a cluster of risk factors that increase the risk of
coronary artery disease, and are known as insulin resistance syndrome or syndrome X. The
gerbil, Psammomys obesus is characterized by primary insulin resistance and is a welldefined model for dietary induced type 2 diabetes. Weanling Psammomys and Albino rats
were held individually for several weeks on High Energy (HE) and Low Energy (LE) diets in
order to determine the development of metabolic changes leading to diabetes. Feeding
Psammomys on HE diet resulted in hyperglycemia (303±40 mg/dl), hyperinsulinemia (194±31
µU/ml) and moderate elevation in body weight, obesity and plasma triglycerides. Albino rats
on HE diet demonstrated elevations in plasma insulin (30±4 µU/ml), hyperglyceridemia
(170±11 mg/dl), elevation in body weight and obesity, but maintained normoglycemia (98±6
mg/dl). Psammomys represents a model that is similar to human populations with primary
insulin resistance expressed in juveniles, which leads to a high percentage of adult type 2
diabetes. Examples of such populations are the Pima Indians, Australian Aborigines and
many other third world populations. The results indicate that the metabolism of Psammomys
is well adapted towards life in a low energy environment, where Psammomys takes
advantage of its capacity of constant accumulation of adipose tissue that will serve it for
maintenance and breeding in periods of scarcity. This metabolism is known as thrifty
metabolism and is compromised at a high nutrient intake.
VIRAL DISEASES IN PET BIRDS IN ISRAEL
U. Bendheim, Koret School of Veterinary Medicine, Hebrew University
Viral diseases diagnosed in Israel were described, including suspect diagnoses based on
clinical and pathological lesions even without virus isolation. Vaccination possibilities are
discussed.
Disease
Pox
Diagnosis
years
1966-2002
Species
Israel
Canaries
lovebirds
in
Known hosts
Vaccines
&
Most avian
species
Homologous
vaccine
Virus
identification
+
for canaries
NCDV
1994-2002
Different
psittacines
Most avian
species
pigeons
&
poultry
Inactivated
vacc.
+
(paramyxo 1)
& canaries
for
psittacines
& pigeons;
Live vacc.
Polyoma
1993-2002
Different
psittacines
Psittacines
and
passerines
PBFD
1991-2002
Different
psittacines,
for
passerines
Inactivated
vacc.
+
For
psittacines
sittacines
in USA*
None
+
Psittacines
None
-
Young
Psittacines
None
maily
cockatoos
PPDD
2000
&
gray
parrots
Macaws
Psittacines
2000
Macaws
Viral
Serositis
1992-2002
Macaws
Psittacines
Autogenic
vaccine*
& passerines
-
(PVS)
Papilloma
Diagnostic methods used:
Pox - virus isolation and histopathology
NCDV - virus isolation and ELISA (Immunocomb)
Polyoma - PCR
PBFD - PCR, histopathology and electronmicroscopy
PPDD, PVS & Papilloma - typical clinical and pathological lesions
* Not in use in Israel.
USE OF LUFENURON FOR TREATING FUNGAL INFECTIONS OF DOGS
AND CATS: A SUMMARY OF 297 CLINICAL CASES (1997-1999)
Y. Ben Ziony and B. Arzi
Ben Ziony Animal Hospital, Kiryat Tivon, Israel
Lufenuron (PROGRAMTM) is an orally administered flea control drug, which acts by inhibiting
chitin, liqueflies the eggshell, and so prevents flea multiplication. Fungal cells are also
surrounded by a cell wall composed of complex polysaccharides, primarily chitin.
Medical records of 138 dogs and 159 cats with dermatophytosis or superficial
dermatomycosis and treated with lufenuron, are reviewed. Sixty untreated dermatophytic
animals are included as controls. Fungal cultures and direct microscopic identification were
performed. The cats were given 51.2 to 266 mg lufenuron/Kg. B.W. The dogs received 54.2 to
68.3 mg. Lufenuron/Kg.B.W.
Recovery in cats was extremely rapid: hair started to grow after 5 or 6 days of treatment. The
mean clinical recovery time was 11.6 days, while the mean mycological cure time was 8.3
days.
In dogs, mean clinical recovery time was 21 days, and mycological cure time in 14.5 days.
Negative fungal cultures always preceeded clinical recovery. No side effects or toxicity were
encountered. Blood profiles remained unchanged. Untreated control animals recovered
spontaneously in 90 days. Treatment aims are to reduce transmission to others and eradicate
infection.
Since the speed of recovery and the lack of side effects are the most important factors in
evaluating drug efficacy, lufenuron is now the fastest, most effective and most convenient
treatment of superficial fungal infections in dogs and cats, currently available. For best results
the dosage in dogs and cats is 80 mg/kg, and in catteries it is 100 mg/kg. A second treatment
two weeks later should be considered since there is remission in 5% of cases fllowing the first
treatment.
Series of photomicrographs depicting the morphological stages of the destruction of various
elements of the fungus as they undergo degeneration, destruction and lysis following
treatment with lufenuron are presented. Such photos of sequential stages in the destruction of
fungal elements as a result of anti fungal drug activity and its mode of action in vivo has never
been communicated or presented in veterinary or human medical text books.
Reference:
Ben Ziony, Y. and Arzi, B.: Use of lufenuron for treating fungal infections of dogs and cats:
297 cases (1997-1999), JAVMA 217: 1510-1514, 2000.
ESTABLISHMENT OF IMMUNE COMPETENCE IN AVIAN GALT DURING THE
IMMEDIATE POST-HATCH PERIOD
E. Ben-Shira, D. Sklan and A. Friedman
Section of Immunology and Nutrition, Department of Animal Sciences, Faculty of Agriculture,
Food and Environmental Quality Sciences, Hebrew University of Jerusalem.
Population dynamics of intestinal lymphocytes and the temporal development of lymphocyte
function were studied in broiler chicks during the first two weeks post-hatch. This period of the
major immunological importance since the chick is immediately exposed to environmental
antigens, while it is devoid of post-hatch maternal immunity. We show that GALT contains
functionally immature T and B lymphocytes at hatch, and that function is attained during the
first two weeks of life as . Functional maturationdemonstrated by mRNA expression of both
IL-2 and IFN occurred in two stages: the first - during the first week post-hatch, and the
second during the second week, which was also accompanied by an increase in lymphocyte
populations. Evidence is presented to show that in the intestinal milieu cellular immune
responses mature earlier, and are a prerequisite for humoral responses. Hence, the lack of
antibody response in young chicks is primarily due to immaturity of T lymphocytes.
CHICKEN FEATHERS: A DNA SOURCE FOR STUDIES ON ONCOGENIC VIRUSES
I. Davidson and R. Borenshtain
Division of Avian diseases, Kimron Veterinary Institute, P. O. Box 12, 50250 Bet Dagan, Israel
Two virus types, Marek’s disease virus (MDV), a herpesvirus, and retroviruses REV, ALV-J
are oncogenic and immunosuppressive in chickens. The feather follicle epithelium was
demonstrated as the site for MDV productive replication and excretion of stable, enveloped
and infective extra-cellular virions. In contrast, retroviruses differ in being unstable in the
environment and their dissemination depends on direct contact between the birds. However,
ALV-J appeared as an exception, as judged by reports on its efficacy for horizontal infection.
As the four viruses reside in white blood cells the molecular differential diagnosis of avian
oncogenic viruses was documented as very efficient using DNA extracted from visceral
organs. However, with the emergence of ALV-J and having in mind the convenience of using
feathers for diagnosis, we reassessed the relevance of the feathers for this purpose. Various
clinical syndroms are caused by the four oncogenic viruses in various types of chickens,
therefore the conclusion to use feathers instead of visceral organs for PCR might differ. For
this reason we analysed several types of cases, and for each type the efficiency of diagnosis
was determined by analyzing the spleen, liver, brain and feathers of each individual bird.
ISRAEL TURKEY MENINGO-ENCEPHALITIS VIRUS: RECENT MOLECULAR FINDINGS
AND A COMPARISON OF VACCINE AND FIELD VIRUSES
C. Banet, Y. Weisman, L.Simanov and M. Malkinson
Kimron Veterinary Institute, P. O. Box 12, 50250 Bet Dagan, Israel
Israel turkey meningo-encephalitis virus (ITME) is an arboviral disease of domestic turkeys
that was first described by Komarov and Kalmar in 1960. The causal agent is a flavivirus
belonging to sero-group N’taya. The disease occurs in turkey flocks over 8 weeks old during
August through November when mosquito activity is greatest. Morbidity in unvaccinated
flocks can be as high as 90%, and mortality is generally between 15-30%. An attenuated
vaccine has been available continuously since its development in 1974.
Over the past 25 years outbreaks of ITME have appeared in non-vaccinated flocks, while in
some years there were more cases than in others. This occurred most recently in 1997 when
from this year to the present, 18 isolates from affected vaccinated and non-vaccinated flocks
have been studied. The E gene of the isolates has been partially sequenced (897
nucleotides). In comparison with the vaccine strain, out of 299 amino acids identified, a total
of 22 sites (7.3%) were shown to be different from the vaccine virus sequence and of which, 7
sites were shared by all 18 isolates (2.3%). The remaining 15 amino acid changes were
distributed among the 18 isolates.
According to these findings, one explanation for vaccine failure may be due to the emergence
of novel antigenic sites in the envelope protein of the field isolates that are not expressed by
the vaccine strain. This can result in the incomplete protection afforded by the vaccine.
THE RELATIONSHIP BETWEEN INTRAOCULAR PRESSURE AND
REPRODUCTIVE STATUS IN CATS
R. Ofri1, N. Shub2, Z. Galin2, M. Shemesh3 and L. Shore3
1. Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Israel
2. Department of Veterinary Services, Tel-Aviv Yaffo Municipality, Israel
3. Endocrinology Unit, Kimron Veterinary Institute, P. O. Box 12, 50250 Bet Dagan, Israel.
Purpose: In 1999, we reported that intraocular pressure (IOP) in lions is affected by the
animal’s reproductive status, with significantly lower IOP values recorded in non-luteal
animals. The aim of this study was to investigate whether a similar relationship exists in the
domestic cat.
Methods: In an attempt to find a humane solution to the problem of overpopulation of stray
cats, the Department of Veterinary Services, Tel-Aviv Yaffo Municipality, routinely neuters
(and releases) stray cats. Seventy-five cats scheduled for neutering were anesthetized with
an intramuscular injection of ketamine and xylazine. Tonometry was performed using an
applanation Tono-Pen. The reproductive organs were examined at the time of surgery to
determine the reproductive status of the animal, and radioimmunoassay was conducted to
determine levels of progesterone.
Results:
Status
n
Progesterone
Mean IOP±SD
(ng/ml)
(mm Hg)
Males
28
<0.3
18.7±3.6
Females not in heat
21
0.8±0.7
16.9±3.2
Females in heat
13
0.8±0.4
20.7±5.2
Pregnant - high
progesterone
8
>3.0
20.6±4.0
Pregnant - low
progesterone
5
<2.0
14.4±4.5
1. IOP in females that are in heat is significantly higher than in females that are not in heat
(P<0.001)
2. IOP in pregnant cats with low progesterone levels is significantly lower than in any other
female of male group (ANOVA: P<0.05).
Conclusions: IOP in female cats is affected by the animal’s reproductive status. IOP in
females in heat is significantly higher than in females that are not in heat. It appears that while
progesterone plays a role in regulating IOP in cats, other reproductive parameters may also
contribute to pressure regulation in this species. Identifying these factors will further our
understanding of the physiological mechanisms responsible for IOP regulation.
FELINE HAEMOBARTONELLOSIS IN ISRAEL: A RETROSPECTIVE
STUDY OF 46 CASES, AND ITS RELATION TO FeLV AND FIV
INFECTIONS
T. Stein1, E. Klement2, G. Baneth1, I. Aroch1, H. Barak1, E. Lavy1 and S. Harrus1
1. Koret School of Veterinary Medicine, The Hebrew University of Jerusalem
2. Center for Vaccine Development and Evaluation, Israel Defense Force
Forty-six cases of naturally occurring clinical feline haemobertonellosis (FH) in Israel are
summarized. Seventy five percent of cats in the present study were at the age of 2.5 years or
below, and the disease was more prevalent in male cats (50% intact males and 19.5%
castrated males). Predominant signs of FH were tachypnea, lethargy, depression, anorexia,
infestation with fleas, pale mucous membranes, icterus, emaciation, dehydration,
splenomegaly, anaemia, leukocytosis, increased ALT and AST activities, and azotemia.
Thirty-eight percent and 22% of cats that were tested for FeLV antigen and FIV antibodies
respectively were found to be positive. The prevalences of FeLV and FIV in this study were
much higher than those in the general Israeli cat population. Cats coinfected with H. felis and
FeLV had significantly lower body temperature, were more anaemic and the mean cell
volume of their erythrocytes was higher compared to cats suffering from FH only. These
findings suggest that cats coinfected with H. felis and FeLV suffer a relatively more severe
disease than cats infected with H. felis only. Nevertheless, coinfection with FeLV was not
found to be a prognostic indicator for poor, short term, survival.
CANINE SPIROCERCOSIS: A RETROSPECTIVE STUDY
M. Mazaki-Tovi1, G. Baneth1, I. Aroch1, S. Harrus1, P. H. Kass2, T. Ben-Ari1, G. Zur1, I.
Aizenberg1, H. Barak1 and E. Lavy1
1. Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Israel
2. School of Veterinary Medicine, University of California, Davis, CA, USA
The nematode Spirocerca lupi is a parasite of dogs with several species of beetles serving as
intermediate hosts. The medical records of 50 dogs diagnosed with spirocercosis at the
Hebrew University Veterinary Teaching Hospital in Israel during 1991-1999 were
retrospectively reviewed and compared to a control group (n=100). There was a 7-fold
increase in the annual number of dogs diagnosed with spirocercosis during these years while
the hospital case load increased by 80%, indicating an emerging outbreak of this infection.
Dogs from the greater Tel-Aviv area were at the highest risk of being diagnosed with
spirocercosis with 74% of the cases originating from this area compared to only 17% of the
controls. The disease appeared to have a primarily urban pattern of distribution with a
significantly higher percentage (p=0.025) of dogs from cities vs. rural areas, as compared to
the control group. Sixty-two recent cases were diagnosed during the colder months of
December through April. This correlates with the completion of a 6-month life cycle in the dog
after infection during the warmer months when vector beetles are abundant. The median age
of infected dogs was 5 years, with dogs 1 year old or younger at the lowest risk of being
diagnosed with spirocercosis. Large breeds were at a higher risk of infection compared to
small breeds. The Labrador Retriever was significantly over represented (p=0.027) in the
study group compared to the control population. The most common signs were vomiting or
regurgitation (60%), pyrexia (24%), lethargy (22%), respiratory abnormalities (20%), anorexia
(18%), melena (18%) and paraparesis (14%). A caudal esophageal mass was identified by
radiography in 53% of the dogs and spondylitis of the thoracic vertebrae in 33%. Fecal
flotation was positive for S. lupi eggs in 80% of the dogs, and endoscopy was found to be the
most sensitive diagnostic procedure and enabled diagnosis in 100% of the examined dogs.
Fifty-three percent of the dogs were anemic and creatine kinase activities were elevated in
54%. Necropsy of 14 dogs revealed esophageal or gastric granulomas in 13 dogs, and an
esophageal osteosarcoma in a single animal. Aortic aneurysmas were found in 6 (43%) dogs.
Fifteen of 24 dogs (63%) for which follow-up information was available died or were
euthanized within 1 month of admission. The case-fatality rate decreased towards the end of
the study period when improved therapy with avermectins became available.
ONCOGENIC POTENTIAL OF LENTIVIRUSES IN ANIMAL ANALOGS
K. Perk
Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot Campus,
Israel
Lentivirus infections in sheep (Maedi/Visna (MV)) and in goats (caprine arthritis-encephalitis
virus (CAEV)) are generally considered nononcogenic. However, tumor association,
lymphoproliferation and infiltration in many organs and interstitial, muscular and alveolar
epithelial cell proliferations are all characteristics of these lentivirus diseases. In severe cases,
the lymph nodes may be composed of uniformly dense populations of lymphoblasts. In the
ovine and caprine lungs, hyperplasia of smooth muscle cells and fibroblasts as well as
epithelial hyperplasia are generally seen. Epithelialization can be very severe, and
ultrastructural and histochemical studies revealed that the cells are type B - alveolar cells. In
addition to alveolar epithelialization, especially seen in older goats with CAEV, proliferation of
these epithelial cells may form acini and papillary structures, histologically indistinguishable
from tumor modules seen in sheep pulmonary adenomatosis. The lentivirus oncogenic
potential is further indicated by the fact that following subcutaneous lentivirus inoculation of
nude mice, lymphoid tumors developed at the site of inoculation and in vital organs. In view of
these findings, the potential role of lentivirus in tumorigenesis in these animal analogs will be
discussed.