Epidemiology of tuberculosis - newer developments and trends

Nearly 2 billion persons and this means about one third of the world’s population are infected with tuberculosis (TB) bacteria, namely Mycobacterium tuberculosis. Not everyone, who is infected, develops the disease and asymptomatic latent TB infection is most common. However, each year, nearly 9 million people develop active TB, the infectious form of the disease. In the patients, where TB becomes an active disease, more than 75% of these cases affect the lungs (pulmonary TB). Symptoms include a productive, prolonged cough of several weeks duration, chest pain, and later coughing up blood. Systemic symptoms include fever, chills, night sweats, appetite loss, and weight loss. If TB is not treated, more than half of the patients die.