Few countries using
vaccines have effectively decreased incidence of clinical JD. In
this study efficacy of indigenous inactivated vaccine containing
highly virulent field strain of Mycobacterium avium
subspecies paratuberculosis (MAP) 'Bison type'
was compared with 'Commercial Inactivated Vaccine' for
the recovery from clinical JD in naturally infected goats. A total
of 71 adult, weak, infected (culture and sero-positive), ready to
cull goats belonging to farm units of Central Institute for
Research on Goats (CIRG), Makhdoom (endemic for JD), were randomly
divided into 3 groups. 'Group- A' of Indigenous
vaccine, 'Group- B' of Commercial vaccine and
'Group- C' of Sham Immunized' controls. After
vaccination, physical condition, body weight gained, fecal shedding
of MAP, humoral and cell-mediated immune responses, mortality and
morbidity etc., were monitored for 7 months. At the end of trial
there was marked overall improvement in body condition of the
vaccinated animals (Group A and B) as compared to
'Group-C'. Body coat showed marked improvement in
shining, pliability, smoothness, regained luster and re-generation
of hairs. Many of the goats kidded, delivering healthy kids and
marked improvement in milk production. Average body weights gained
per animal were significantly high (p<0.05) in the goats of
Group-A as compared to Group B and C. Mortality and morbidity rates
(due to diarrhea, weakness and Johne's disease) were lower in
'Group-A' goats as compared to 'Group-B'
and 'Group-C' goats. Gross lesions in goats died and
necropsied from vaccinated groups (Group A and B) during the study
showed regression of lesions of JD and regeneration of fat, while
'Sham immunized' goats had frank lesions of JD.
Lymphocyte transformation test (LTT) (indicator of cellular
response) showed higher stimulation of PBMCs in
'Group-A' animals with MAP antigen as compared to PBMCs
in 'Group-B' and 'Group-C' goats.
Concentration of nitric oxide, (cellular response), was also higher
in 'Group-A' goats followed by 'Group-B'
and 'Group-C'. Goats of both vaccinated groups also had
higher protective antibody titer in comparison to
'Sham-immunized' goats. Both the vaccines reduced fecal
shedding remarkably but indigenous 'Bison type' vaccine
was more effective. However, few of the very advance cases of
Johne's disease did not recover and died eventually during
the study and at necropsy had frank lesions of JD. Overall both the
vaccines were effective in restricting MAP infection and JD in
clinically infected goats but indigenous vaccine using native MAP
'Bison type' strain of goat origin was superior.