physiological and economic advantages, but also the potential to supplement systemic vaccination. Obstacles in development Treatment and prevention of TB has been delayed compared to the resources and research efforts put into other diseases. Large pharmaceutical companies do not see profitable investment because of TB's association with the developing world. Progression of vaccine designs relies heavily on outcomes in animal models. Appropriate animal models are scarce because it is difficult to imitate TB in non-human species. It is also challenging finding a species to test on a large scale. Most animal testing for TB vaccines has been conducted on murine, bovine and non-primate species. Recently, a study deemed zebrafish a potentially suitable model organism for preclinical vaccine development. References