Definition of "foulbrood"

There were problems in my dad’s day: ants, skunks, wax moths and a couple of deadly but well-known bee diseases, like foulbrood and nosema.

2007 February 22, Verlyn Klinkenborg, “Keeping Bees Among Us”, in New York Times‎

At times nearly all brood diseases (American foulbrood, European foulbrood, parafoulbrood, sacbrood) were thought to represent a single malady. European and American foulbroods were especially confused.

2012, Edward Steinhaus, Insect Pathology V2: An Advanced Treatise, page 553