Oral and Poster Abstracts

Italy. After the sample examinations, 90 (1.69%) were positive, 146
(2.75%), doubtful, 77 (1.45%) anti-complementary and 4993 (94.13%)
were negative. At the reanalyzing of those positive, doubtful and anticoplementary
samples after a short period of time all of them were
negative. The specificity of CFT had been calculated using both
antigens and the following results were obtained: 95-99% with
Portuguese antigen and 82-100% with Italian antigen. From the 649
CFT examined samples using the Italian antigen which revealed a
specificity of 82%, we examined by competitive ELISA (cELISA) all
the positive (20), doubtful (85), anticomplementary (6) and 59 negative
samples. From 170 examined samples only 12 presented doubtful
results and the others were negative. For the introducing in the routine
work of cELISA we also evaluated the precision parameter of the
method by calculation of the repeatability and reproducibility of the
obtained results. The variation coefficient (CV) of the reproducibility
of control sera obtained results had been between 6.3% and 6.8% in
comparison with 8% CV reported by the producer. Taken into
consideration that cELISA had revealed a very good specificity of 92%
and a correlation index of 41.76% against CFT results it is
recommended that any anticomplementary, doubtful or positive results
in CFT to be also analyzed by cELISA.
Key words: M. mycoides, CFT, ELISA, CPBB, antigen
651 Compatibility of Inactivated Bovine Viral Diarrhoea (BVD)
and Leptospira Interrogans Serovar Hardjo Vaccines
I. Mawhinney 1 , B. Makoschey 2
1 ICM Broadlands, Bury St. Edmonds, United Kingdom
2 Intervet-Schering Plough, Int. Marketing, Boxmeer, The Netherlands
Objectives: The purpose of this study was to examine whether concurrent
administration of a Leptospira vaccine affects the immunogenicity of an
inactivated bovine viral diarrhoea (BVD) vaccine.
Materials and Methods: Twenty beef breeding animals were included
in the trial. At the beginning of the study, one animal had very low
antibody titers against BVDV the remaining animals were
seronegative. All animals were seronegative for Leptospira prior to the
vaccinations. All animals were vaccinated intramuscularly with a
commercially available BVD vaccine (Bovilis ® BVD, Intervet). Ten of
them (group A) were vaccinated subcutaneously at the same time but
on the opposite site of the neck with an inactivated Leptospira
interrogans serovar hardjo vaccine (Leptavoid ® H, Schering Plough).
The remaining 10 animals (Group B) were vaccinated two weeks later
with the Leptospira vaccine following the manufacturer
recommendation. The BVD vaccination was repeated after four weeks
in both groups. The animals of group A received a second dose of the
Leptospira vaccine at the same time. The animals of group B were revaccinated
with the Leptospira vaccine 2 weeks after the BVD booster.
Blood samples were taken at the first and second BVD vaccination
(days 1 and 28) and two and four weeks after the second vaccination
(days 42 for group A and 42 and 56 for group B). The samples were
processed into serum for antibody testing. Antibodies specific for BVD
virus were measured by serum neutralisation test. Leptospira serology
was carried out against each of the two hardjo serovars, prajitno and
bovis using a standard MAT test (VLA, Weybridge).
Results: There was no statistically significant difference when the
serological response to the BVD vaccine was compared between the
two groups. Likewise, there was no statistically significant difference
in the Leptospira serology, neither for prajitno, nor for bovis when the
antibody responses two weeks after the second dose of the Leptospira
vaccine was compared between the two groups.
Conclusions: From these data it was concluded that there was no
negative effect on the neutralising antibody response when the two
vaccines were applied concurrently (at the same time but on opposite
sides of the animal).
652 Simultaneous Infection of Calves with Maternal Antibodies
with Bovine Rotavirus and Coronaviruses under
Experimental Conditions
U. Schmidt 1 , M. Timmermans 1 , P. Tonen 1 , B. Makoschey 2
1
Intervet-Schering Plough, R&D, Boxmeer, The Netherlands
1
Intervet-Schering-Plough, Int. Marketing, Boxmeer, The
Netherlands
Objectives: Newborn calf diarrhoea is generally recognized as
multifactorial disease. The list of pathogens that can be involved is
88 XXV. Jubilee World Buiatrics Congress 2008
quite extensive, comprising bovine rotaviruses, bovine coronaviruses,
E. coli and Cryptosporidium parvum as the most important ones. In the
present study, clinical signs after simultaneous infection of newborn
calves with two rotaviruses and a coronavirus under laboratory
conditions should be compared to the infection with either of the three
pathogens alone. Moreover, it should be investigated, whether all three
viruses replicate after co-infection.
Materials and Methods: The experiment was divided in four separate
studies. On days 5, 6 and 7 after birth, the calves were infected orally
with bovine rotavirus P5G6 (study 1), bovine rotavirus P11G10 (study
2) and bovine coronavirus DB-2 (study 3) or all three viruses together
(study 4). After the infection, the calves were observed twice daily for
clinical signs of diarrhoea. From the day of infection onwards, fecal
samples were taken twice daily. Virus shedding was quantified by
ELISA technique.
Results: All 12 animals infected with a single virus survived until the
end of the observation period and some animals developed only very
mild or no diarrhoea. By contrast, all four animals infected
simultaneously with all three viruses had liquid faeces during at least
one observation moment and two of the four animals had to be killed on
humane reasons after episodes of severe diarrhoea. Both, rotavirus and
coronavirus was detected in the faeces of all four animals infected
simultaneously with the three viruses during several days. Moreover,
both rotavirus G-types were present in a faecal sample from a coinfected
calf.
Conclusions: From these data, it can be concluded, that the coinfection
of calves with rota- and coronaviruses under laboratory
conditions reflects the field situation, where co-infection of
pathogens causes more severe disease than infection with single
pathogens. Moreover, the results reported here confirmed, that
colostrum from unvaccinated dams did only partly protect against
diarrhoea. Experimental data and field experiences have
demonstrated the benefit of cow vaccination against enteric
pathogens.
653 Serum-free Produced Live Virus Vaccines are Efficacious and
Safe
B. Makoschey 1 , P. Gelder 2
1 Intervet-Schering Plough, Int. Marketing, Boxmeer, The Netherlands
2 Intervet-Schering Plough, R&D, Boxmeer, The Netherlands
Objectives: Most cell culture based manufacturing processes for
animal and human vaccines use bovine fetal serum (FCS). In potential,
FCS can be contaminated with a number of viruses that can infect the
bovine foetus transplacentally, especially with the bovine viral
diarrhoea virus (BVDV). Therefore, we have developed a novel
production procedure for bovine herpesvirus type 1 (BoHV-1) live
virus vaccines that does not make use of serum or fractions thereof
during any cell or virus passage, thus completely serum-free. It should
be determined whether serum-free produced BoHV-1 viruses are
suitable as live vaccines for use in cattle.
Materials and Methods: The safety of serum-free produced BoHV-
1 virus was established in two separate studies. In the first study, six
colostrum deprived calves each were vaccinated intranasally (IN) or
intramuscularly (IM) with an overdose and two weeks later again
with a single dose. In a second study, ten seronegative calves at the
age of five to six months were vaccinated four times at fortnightly
interval with an overdose, both IN and IM. The efficacy was tested
in a vaccination-challenge study in seronegative calves as laid down
in the European Phamacopeia. For comparison, a vaccine batch with
BoHV-1 grown in serum-containing cell culture medium was
included in the study. The calves were monitored for clinical signs
after challenge infection with BoHV-1 wild type virus and challenge
virus excretion was measured. Finally, the stability of the virus was
determined by titration of the freeze-dried vaccine after storage at
temperatures of +4˚C and -20˚C for more than one year.
Results: There were no local or systemic reactions after vaccination
observed in either of the two safety studies. With regard to efficacy, the
serum-free produced vaccine performed equally well as the
conventionally produced one and both met the strict requirements as
laid down in the European Phamacopeia. Finally, the virus titers of the
freeze-dried vaccines were stable for more than one year at
temperatures of +4˚C and -20˚C.
Conclusions: These data demonstrate the safety and efficacy of serumfree
produced live vaccines in cattle as well as the stability of these
products.