ASSESSMENT OF IMMUNITY TO DUCK PLAGUE VIRUS (DUCK VIRUS ENTERlTlS) ON VACCINATION
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Date
1993
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR
Abstract
During 1991, six outbreaks clinically
duck plague (DP) with 33 per cent morbidity
mortality were investigated. Duck plague
from each outbreak. The isolates were able
lesions and death of the duck embryos but fai
chicken embryos during initial passages.
suspected to be
and 26 per cent
was isolated
to produce the
led to kill the
One of the strain, named DP-S was par
by 10 passages in chicken embryos following
duck embryos. Though the attenuated strain did
pathogenicity index was reduced from 1.9 to 1.
DP-S under transmission electron microscope
of herpes virus morphology.
Two DP vaccines - commercial vaccine
vaccine having virus titres 0.74 and 3.5
respectively, were separately inoculated into
ducklings respectively, two groups receiving
two receiving double dose of corresponding
interval of four weeks. Another group of duckl
as control without vaccination.
tially attenuated
20 passages in
kill ducks, its
23. The isolate
revealed virions
and lab-adapted
log 10 ELD 50/ml
four groups of
single dose and
vaccines at an
ings was kept
(ii)
challenged with Thre e ducks in each group were
virulent DPV at four,eight and 20 weeks post-vaccination. The
birds in all the five groups were screened at regular
intervals for studying the immune response by virus
neutralization (VN), leucocyte migration-inhibition (LMI) and
passive haemagglutination (PHA) test.
The challenged and survived birds were
the carrier status of DPV by examination of their
for virus isolation.
In an organized farm, 180 ducks were gi
vaccine at one year of age and were scre
antibodies, LMI response and PHA titres before
post-vaccination. Randomly selected two birds
six weeks post-vaccination.
The findings of the study are briefly l
Six duck plague outbreaks were investigat
isolated, and characterized. It was
in duck and chicken embryos.
partially
The commercial vaccine could elicit very
response as compared to laboratory adapted
immunity could not last long even upto ei
single vaccination and 20 weeks in double
screened for
rectal swabs
ven commercial
ened for VN
and eight weeks
were challenged
isted as under:
ed, the virus
attenuated
poor immune
vaccine. The
ght weeks in
vaccination.
(iii)
* Single vaccination is not effective as c
vaccination given four weeks apart.
The assessment of antibody-mediated (AMI) and cell mediate d (CMI) immune responses indicated
that both and CMI are involved in protection of ducks against duck plague.
The vaccinated or vaccinated and infected
show carrier status as attempts to isolate
rectal swabs collected after vaccination
were unsuccessful.
The PHA has been standardized for
diagnosis of duck plague.
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