The pathogenicity for honey-bee larvae of microorganisms associated with European foulbrood

Tests made on larvae in normal bee colonies with pure cultures of Streptococcus pluton (White), Streptococcus faecalis Andrews and Horder, and Bacillus alvei Cheshire and Cheyne, three bacterial species commonly associated with European foulbrood (EFB), showed that S. pluton was the natural prirnary etiological agent. These results, together with other recent work, indicate that S. pluton is the cause of EFB throughout the world. Of the other associated bacterial species, Bacterium eurydice White, which is the most commnon, and S. faecalis probably have supplementary pathogenic effects. Bacillus alvei and other less common bacilli are saprophytes of the dead larvae.