Oral vaccination with Mycobacterium bovis BCG in a lipid formulation induces resistance to pulmonary tuberculosis in brushtail possums

Oral vaccination reduces the incidence of tuberculosis in free-living brushtail possums

“…This is in contrast with the previous trials with captive possums, where significant systemic cell-mediated immune responses to similar BCG dosages have been observed at 6þ weeks post-vaccination (Aldwell et al 2003a), in addition to a strong relationship between the proportion of animals producing positive LP responses to M. bovis antigens and protection against artificial challenge with M. bovis . The comparison of LP responses of vaccinated possums and controls here was probably confounded by actual Tb infection, since two of the control animals were positive responders to the assay (SI .…”

“…Vaccine efficacy was similar in both sexes, even though the transition probability from susceptible to Tb infected was, as discussed earlier, greater for males than females. In addition, although not much weight can be placed on the observation that infection was less severe (in terms of number and size of lesions) in the single infected vaccinated animal compared with the infected controls (appendix B, electronic supplementary material), this is consistent with previous work showing that in cases where oral vaccination does not prevent Tb infection, it does slow and possibly prevent disease progression (Aldwell et al 2003a;Buddle et al 2006;Ramsey et al 2009). This high level of vaccine efficacy compares very favourably with other wildlife vaccines.…”

“…Studies in a range of animal species have shown that oral vaccination with this lipid-formulated BCG can induce a level of protection against experimental challenge with Tb that is comparable with that induced by injecting the vaccine (Aldwell et al 2003a,b;Buddle et al 2006;Nol et al 2008). However, vaccination has generally not prevented animals from becoming infected as a result of experimental challenge; rather, it has slowed the progression of the disease relative to that in unvaccinated animals, as shown by a reduction in the severity of disease and bacterial counts in lungs and spleen (Aldwell et al 1995(Aldwell et al , 2003aBuddle et al 2006).…”

Vaccination of white-tailed deer (Odocoileus virginianus) with Mycobacterium bovis bacillus Calmette Guerín

“…Oral or intragastric vaccination of brushtail possums (Trichosurus vulpecula) with M. bovis BCG produces inferior protection to intraduodenal vaccination [38][39][40]. However, lipid based preparations to protect live M. bovis BCG from the harmful effects of the gastric environment have proven effective in brushtail possum vaccination trials [41].…”

Oral Vaccination of Guinea Pigs with aMycobacterium bovisBacillus Calmette-Guérin Vaccine in a Lipid Matrix Protects against Aerosol Infection with VirulentM. bovis

“…For rodent models and brushtail possums, oral delivery of lipid formulations containing live BCG was shown to establish populations of viable, replicating BCG in the alimentary tract lymphatic system (1,46), which in mice persisted for at least seven months postvaccination (3). Voluntary uptake of the vaccine (which can be readily induced following flavoring of the lipid matrix) was shown to confer protection against virulent M. bovis or M. tuberculosis aerosol challenge in mice (2,3,6) and against challenge to the pulmonary tract with virulent M. bovis in possums and cattle (4,12). The durations of protection after oral vaccination were at least 7 months for mice and 12 months for possums (3,10).…”