Oral re-vaccination of Eurasian wild boar with Mycobacterium bovis BCG yields a strong protective response against challenge with a field strain.
BACKGROUND
Field vaccination trials with Mycobacterium bovis BCG, an attenuated mutant of M. bovis, are ongoing in Spain, where the Eurasian wild boar (Sus scrofa) is regarded as the main driver of animal tuberculosis (TB). The oral baiting strategy consists in deploying vaccine baits twice each summer, in order to gain access to a high proportion of wild boar piglets. The aim of this study was to assess the response of wild boar to re-vaccination with BCG and to subsequent challenge with an M. bovis field strain.


RESULTS
BCG re-vaccinated wild boar showed reductions of 75.8% in lesion score and 66.9% in culture score, as compared to unvaccinated controls. Only one of nine vaccinated wild boar had a culture-confirmed lung infection, as compared to seven of eight controls. Serum antibody levels were highly variable and did not differ significantly between BCG re-vaccinated wild boar and controls. Gamma IFN levels differed significantly between BCG re-vaccinated wild boar and controls. The mRNA levels for IL-1b, C3 and MUT were significantly higher in vaccinated wild boar when compared to controls after vaccination and decreased after mycobacterial challenge.


CONCLUSIONS
Oral re-vaccination of wild boar with BCG yields a strong protective response against challenge with a field strain. Moreover, re-vaccination of wild boar with BCG is not counterproductive. These findings are relevant given that re-vaccination is likely to happen under real (field) conditions.
SaBio IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real, Spain. christian.gortazar@uclm.es.
Christian
C
Gortazar
Beatriz
B
Beltrán-Beck
Joseba M
JM
Garrido
Alicia
A
Aranaz
Iker A
IA
Sevilla
Mariana
M
Boadella
Konstantin P
KP
Lyashchenko
Ruth C
RC
Galindo
Vidal
V
Montoro
Lucas
L
Domínguez
Ramón
R
Juste
Jose
J
de la Fuente
D056704:Adaptive Immunity; D000284:Administration, Oral; D000818:Animals; D001500:BCG Vaccine / Q000008:administration & dosage / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology; D007113:Immunity, Innate; D009163:Mycobacterium bovis / Q000276:immunology*; D013030:Spain / Q000453:epidemiology; D034421:Sus scrofa; D014376:Tuberculosis / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D014611:Vaccination / Q000662:veterinary
D001500:BCG Vaccine