Development of a diagnostic blood test for tuberculosis in alpacas (Lama pacos).

Vaccination of alpacas (Lama pacos) with heat-killed Mycobacterium bovis (BCG) in oil adjuvant produces an immune response that is able to be measured in vitro. Lymphocyte transformation was present 2 weeks after boosting while antibody as measured by the enzyme-linked immunosorbent assay was present 4-6 weeks after primary vaccination. Two vaccinated animals were positive to the intradermal skin test at the conclusion of the experiment and showed signs of systemic inflammation 72 hours after the skin test, while the controls remained negative for all tests. The BCG vaccine studies showed that these laboratory tests can also identify M. bovis-specific reactivity, so the technique has potential for the diagnosis of tuberculosis in alpacas. Apart from diagnosing M. bovis-specific reactivity, the blood test for tuberculosis may also be used to diagnose non-specific mycobacterial sensitisation in farmed New Zealand alpacas.

BCG vaccination in deer: distinctions between delayed type hypersensitivity and laboratory parameters of immunity.

Groups of deer were vaccinated with live or killed Bacillus Calmette-Guerin (BCG), with and without oil adjuvant, to compare their immune responses with those found in naturally infected animals. Killed BCG in oil induced strong lymphocyte transformation (LT) and antibody (ELISA) responses specific for Mycobacterium bovis antigens. Serum inflammatory proteins (SIP) were also induced after these animals were skin tested. This pattern of reactivity mirrored that found in naturally infected deer with active tuberculosis. Animals vaccinated with live BCG without oil adjuvant also produced strong LT reactivity but this was directed at common mycobacterial antigens found on both M. bovis and M. avium, although no antibody or SIP were detected at any stage of the experiment. The pattern of immune responsiveness to live BCG was similar to that found in naturally infected, but non-diseased deer, and may represent the immunoprotective response to tuberculosis. Significant differences in specificity of lymphocyte transformation and intradermal skin test reactivity to mycobacterial antigens were also identified. Vaccination with BCG in various formulations provides an experimental probe to evaluate the immunological basis of immunity to tuberculosis.