What is the difference between etiology and pathogenesis?

Etiology and pathogenesis are very related. Etiology includes risk factors and causative organisms and is the actual cause of disease. Pathogenesis is how those things went about causing the disease: the mechanism of disease.

Example: Tuberculoses

Etiology: intravenous drug user injected, became infected with m. tuberculosis

Pathogenesis: m. tuberculosis invaded into the lung, started destroying tissue, causing cough, etc.

Disease: tuberculosis