Animals play an important role in understanding human disease pathogenesis. In order to study a human disease you cannot, for ethical reasons, conduct the initial studies on humans. Therefore, animal models are needed to replicate the condition and/or disease of interest to a similar degree as seen in humans. It is expected that investigations into these animal models will provide insight into the progression of the disease that can be extrapolated to treating and/or preventing the disease in humans. A model species should be relatively easy to handle and readily available. Additionally, it should be able to recapitulate the disease of interest and give birth to multiple offspring in each gestation. Historically, the most common animal model for human disease is the mouse due to its similarities in anatomy and cell biology. Using transgenic approaches, mouse models can be developed to accurately demonstrate the pathology of the disease. However, other mammalian species, such as swine, are used as successful animal models. Pigs are an attractive animal model for investigating human diseases because of the similarity of pigs and humans in the respiratory and digestive tracts and the immune system. The use of pigs in animal research may provide a more relevant model for translating treatments and prevention of disease to human patients.