MVSc

Use of Enzyme immunoassays namely dot ELISA and plate
ELISA were evaluated to detect DP viral antibodies in serum
samples and in whole blood dried on filter paper strips and
their efficacy was compared with standard passive
haemagglutination test.
Indirect immunoperoxidase test was also used to detect DP
viral antigen in paraffin embedded liver and spleen.
ASS at 33 per cent level was used for separation of duck
globulins and antiduck globulins. The protein concentration
of these globulins were 34 mg/ml and 15 mg/ml respectively.
The purity of these globulins were tested by IEP and AGPT
using antiduck whole serum raised in rabbits.
Duck plague hyperimmune serum was raised in healthy
ducklings with live attenuated DP vaccine having a virus titre
of 3.5 log10 ELD50/0.5 ml. This serum was used as the positive
control.
A total of 200 serum samples, 35 liver and 30 spleen
samples were collected from different localities for the
detection of duck plague viral antibodies and antigen.
Corresponding blood samples were also collected on filter
paper strips and the serum was eluted and ELISA was carried

out. The results in this test were then compared with whole
serum ELISA.
The percentage of positive reaction in PHA, Dot ELISA,
plate ELISA and filter paper strip method are 64 per cent, 68
per cent 72.5 per cent and 70.5 per cent respectively.
Comparative efficacy of PHA with Dot ELISA, plate ELISA
and filter paper strip method were carried out and sensitivity
of the tests are 71.87, 67.64 and 77.30 per cent respectively.
The specificity of these tests were 38.88, 43.75, 70.90 and
67.79 per cent respectively. The concordance of PHA with
these tests were 60, 75.5 and 74.5 per cent respectively.
On statistical analysis high degree of association
(P<0.05) was observed between PHA and Dot ELISA, plate ELISA
and filter paper strip method. Highly significant different
(P>0.05) was observed between PHA and plate ELISA, and PHA and
filter paper strip method.
Based on the results, it was concluded that because of
the simplicity, easiness and accuracy, Dot ELISA is suitable
for detection of DPV antibodies under field conditions.
But plate ELISA was highly sensitive, specific and able
to detect low titred sera. Hence this test may be recommended
for titration of DPV antibodies in the laboratories,



particularly when the potency of the vaccine is to be checked
and the immune status of a flock is to be evaluated.
Because of various advantages filter paper strip method
will serve as an alternative to collection of whole serum for
detection of DPV antibodies. For the detection of DPV
antigen, IPT was considered as suitable one because of its
ability to detect high positive (83%) cases and less non
specific reactions.