1. Tuberculosis

2. Tuberculosis Causative agent: Mycobacterium tuberculosis
Morphological and cultural properties:
In tissue, tubercle bacilli are thin straight rods measuring about .4 X3 µm
The rods grow slowly (20 hours or longer generation time).
Sometimes form filamentous or tend to grow in clumps.
Can not be classified as either G+ve or G-ve.
They are called acid fast bacilli.
They are obligate aerobes and derive energy from the oxidation of many simple carbon compounds.
tubercle bacilli are resistant to drying and survive for long periods in dried sputum (a mixture of saliva and mucus coughed up from the respiratory tract, typically as a result of infection or other disease and often examined microscopically to aid medical diagnosis )

4. Pathogenesis of tuberculosis

5. Pathogenesis of tuberculosis
If the infection progresses, the host isolates the pathogens in a walled off lesion called a tubercle (meaning a lump or knob), a disease that gives the disease its name.
When the disease is arrested at this point, the lesions slowly heal, becoming calcified. These show up clearly on X-ray films and are called Ghon complexes.
If the body’s defense fail at this stage, the tubercle breaks down and releases virulent bacilli into the airways of the lungs and then the cardiovascular and lymphatic systems.

6. Clinical finding Fatigue, weakness, weight loss and fever
Pulmonary involvement giving rise to chronic cough and splitting of blood usually is associated with far-advanced lesions.
Bloodstream dissemination leads to miliary tuberculosis with lesions in many organs and high a mortality rate.

7. Prevention of Tuberculosis
The BCG vaccine is a live culture of Mycobacterium bovis (pathogen mainly of cattle, cause of bovine tuberculosis) that has been made avirulent by long cultivation on artificial media.
Mycobacterium bovis is transmitted to humans via contaminated milk or food.
BCG stands for bacillus of Calmette and Guerin, the people who originally isolated the strain.
The BCG vaccine has been available since the 1920s and is one of the most widely used vaccines in the world.
In 1990, it was estimated that 70% of the world's school children received it.