Lecture 4: ancient and re-emergent diseases tuberculosis. Persistence of chronic non-infectious diseases, newly emergent and re-emergent infectious disease. Infectious diseases notable for: many new disease causing mortality being detected. Increased incidence and prevalence of previously controlled (re-emergent) infectious disease: many re-emergent pathogens evolving into drug-resistant strains. Only 5-10% of those infected will develop active tb. Most cases of active tb from adult re-activation of earlier (latent) exposure (despite. Once inhaled: focuses in the lung, body responds by developing a granuloma to wall off the bacillae called a tubercle. Chronic cough (blood), fever, chills, weight loss, fatigue, night sweats. With flare-up bacillae increase and breaks from tubercle to spreads throughout body, especially areas of rbc production (especially cancellous bone): ribs, epiphyses, vertebral bodies, pelvis, even skull. In a latent phase of the infection: no symptoms. In early active stages: fever, chills, sweating, night sweats, flu-like symptoms, gastrointestinal symptoms, weight loss, no appetite, weakness, fatigue.