Latent TB infection (LTBI)		The most common result of initial TB infection. This is a condition in which living tubercle bacilli are present in an individual in a latent or dormant state, without producing disease. The infected person, although having a positive tuberculin skin test (PPD positive), has no symptoms or signs of disease, may have a normal chest X-ray, and does not have a positive smear or culture for Mycobacterium tuberculosis. People who have latent TB infection cannot spread the disease. They are at risk, however, of reactivation of their latent infection, resulting in their developing the disease. They can be treated to reduce the risk of their latent infection developing into the disease.
Live-vector vaccine		A vaccine using a non-disease-causing organism (virus or bacteria) to transport TB or other foreign genes (encoding antigens) into the body.
Lyopholize		A dehydration process, commonly referred to as "freeze drying," in which most moisture in a frozen substance is removed under vacuum conditions.