Rheumatic fever develops after streptococcal pharyngitis, inflammation of the throat due to Streptococcus pyogenes where pyogenes literally means “makes pus”. The bacteria is sometimes referred to as “Group A beta hemolytic” streptococcus, and the infection itself is most often just called Strep throat. This particular group of streptococcus has an antigen that lumps it into a group called “group A”, and it also produces an enzyme called streptolysin, that completely lyses nearby red blood cells, or causes them rupture—rupturing red blood cells is called hemolysis, right? And when those red blood cells rupture and are destroyed, it’s called beta-hemolysis—as opposed to alpha-hemolysis, where cells aren’t actually destroyed, they’re just damaged or bruised.