American Foulbrood-Old and Always New Challenge.

American foulbrood (AFB) is exclusively an infectious disease of honey bee larvae () and their subspecies that is spread easily and rapidly and is often present in apiaries. Due to the resistance and pathogenicity of the bacterial causative agent of the disease, which has considerable epizootiological and economic significance for beekeeping, AFB was classified as a highly dangerous, infectious animal disease by the World Organization for Animal Health (WOAH). Considering the severity of the infection, a frequent occurrence, rapid and easy spread, epizooty and enzooty are common. We tried to present an overview of the latest information related to AFB through several chapters. In addition to the latest data on the etiology of the causative agent, the most important elements of the clinical signs of the disease are also listed. Along with an overview of classic microbiological and the latest molecular methods of diagnosis, we also discuss AFB treatment from its differential diagnostic aspect. We hope that through demonstrating the mentioned preventive measures and measures of good beekeeping practice, the review will contribute to the preservation of the health of bees and therefore the overall biodiversity of the planet.