BCG tuberculosis vaccine is safe for use in goats

Vaccination of livestock is increasingly being considered as an alternative strategy for the control of tuberculosis.

In Spain, goat tuberculosis, mainly caused by the Mycobacterium bovis and Mycobacterium caprae, is responsible for significant economic losses due to trade restrictions, and requires the sacrifice of all animals in many of the infected herds. In addition, it has recently been shown that infected goats can be a source of TB infection to cattle farms.

A research team of the IRTA-CReSA, led by Dr. Bernat Pérez de Val, has carried out a test under field conditions to assess safety in goats of BCG, an attenuated strain (that has lost virulence) of Mycobacterium bovis, which is, nowadays, the only available vaccine against tuberculosis for humans. Previously, the same research team had already demonstrated the efficacy of this vaccine in an experimental context to confer protection to goats infected with the bacteria that causes tuberculosis.

The safety study was conducted with dairy goats and their goatlings in the experimental farm of the UAB (‘Universitat Autonoma de Barcelona). The vaccine was not detected neither milk nor in faeces of any of the animals throughout the study, that lasted for 24 weeks. Subsequently the animals were euthanized and a complete necropsy of the animals was performed to find the presence of the vaccine strain in the carcass. Following this thorough evaluation only small nodules were detected in the injection site of the vaccine in some animals. Adverse reactions were, therefore, local and practically insignificant. Bacterial culture showed that in all of these animals the vaccine was biologically inactive and it was unable to generate any virulent effect.

However, the immune response generated by the vaccine was detected after immunization and lasted until the end of the study, indicating that the animals were successfully immunized against tuberculosis.

The results of this study indicate that BCG vaccination is safe for its use in goats, for the environment and for human consumption.

This work has been recently published in the scientific journal Vaccine:

Pérez de Val B, Vidal E, López-Soria S, Marco A, Cervera Z, Martín M, Mercader I, Singh M, Raeber A, Domingo M. Assessment of safety and interferon gamma responses of Mycobacterium bovis BCG vaccine in goat kids and milking goats.Vaccine. 2016 Feb 10;34(7):881-6. doi: 10.1016/j.vaccine.2016.01.004. Epub 2016 Jan 13.

These studies were funded by the Agriculture department (DARP) of the Catalan government, and by a research project from ‘Plan Nacional de I+D+idel MINECO’ (Ref. AGL2012-36171) led by the ‘Universidad Complutense de Madrid’.