Immune Responses to Mycobacterium Tuberculosis (Mtb) in People With Latent Tuberculosis Infection With or Without Concomitant Helminth Infection

Background: Tuberculosis (TB) is a severe disease and a major cause of death in many people worldwide. It is caused by a bacteria that enters through the lungs and can spread elsewhere in the body. People with latent TB have the bacteria that lie dormant but can become active and cause disease. These people are offered treatment to prevent development of active TB. Worldwide, a lot of people with LTBI also have a parasitic worm called a helminth that can stay in the gut or the blood. These parasites can affect the immune system and cause diseases like TB to become worse. Researchers want to see how helminth infection makes it harder for people to fight TB infection. Objectives: \- To study how the immune system of people with latent tuberculosis infection (LTBI) acts to prevent development of active TB. Also, to study how helminth infection might affect this immune response. Eligibility: * Adults age 18 70 with LTBI as defined by an approved blood test called QuantiFERON TB Gold. * No evidence of infections like Hepatitis or HIV * Pregnant subjects and subjects taking medications that suppress the immune system are not eligible. * Have not received prior treatment for LTBI. Participants might be still eligible if prior treatment for active TB has been received Design: Screening phase: \- Participants will be screened with medical history, physical exam, and blood tests for other infections/conditions which might affect the immune system. They will have testing for active TB i.e. blood testing as well as testing of their spit, scans and X-rays. Baseline phase: * Only eligible participants will be entered into the study. * Participants will have interviews, medical history, and physical exam. * Blood will be drawn from an arm vein for testing. * Participants will collect stool samples at home for 3 days in a row to test for helminth infection.. * Participants may have apheresis. Blood cells are removed by needle. They pass through a separator machine which r