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OJVRTM
Online Journal of Veterinary Research©
(Including Medical and Laboratory Research)
Established 1994
ISSN 1328-925X
Volume 29 (12): 783-791, 2025.
Effect of intranasal live gdhA P. multocida B:2 on immunity in cattle.
Rafidah
O, Zamri-Saad M, Nasip E, Saharee AA.
Faculty
of Veterinary Medicine, Universiti Putra, Department
of Veterinary Services and Animal Industry, Kota Kinabalu,
Sabah, Malaysia
Abstract
Rafidah O, Zamri-Saad
M, Nasip E, Saharee AA., Effect
of intranasal live gdhA P. multocida
B:2 on immunity in cattle. Onl J Vet Res., Volume 29 (12): 783-791, 2025. The
results of a live attenuated gdhA derivative
P. multocida B:2 vaccine
on immunity in buffalo herds is
described. Three groups of 30 to 50 buffaloes
selected from a haemorrhagic septicaemia-endemic
and non-endemic area were used. Thirty percent of animals in each group were given
intranasal 5 ml inoculum 106 cfu/mL
live attenuated gdhA derivative P. multocida B:2. After
exposure, vaccinated buffaloes were mingled with non-vaccinated animals of the
same group. A booster dose was given 10 months after the first exposure. Serum
samples were randomly collected from 30% of each group before vaccination and at
2-month intervals for 22 months to determine herd immune status by ELISA. Endemic
or non-endemic herd status was compared with 15 non-vaccinated controls. Results
revealed high herd antibody levels in endemic and non-endemic areas before
vaccination. After vaccination, herd antibody levels in both areas gradually
increased to peak values by the 6th month and then started to gradually
decline until month 10. Following booster dose at 10th month,
antibodies declined to levels similar to those in unvaccinated animal at 12 to 14
months. Antibody levels then recovered at 22-months (end of study). It was
concluded that field vaccination using gdhA derivative P. multocida B:2 increased herd
immunity for 8 to 10 months before a booster dose was required.