Answer
Endocarditis is an inflammation of the endocardium of the heart--often only of the heart valves.
Bacterial infections often reach the heart from unsterilized needles used by drug addicts to inject drugs into their veins. This is what probably happened to Gabriel, a heroin user.
Work Step by Step
Some common causes of endocarditis :
1. Bacterial infection
2. Fungal infection
3. Autoimmunity
5. Drug addicts' use of contaminated blood to inject drugs into their veins.
Gabriel was a user of intravenous heroin, and probably got her endocarditis by bacterial
infection acquired through method #5
