American foulbrood and European foulbrood are two different bacterial brood diseases of honey bees. European foulbrood (EFB) is caused by Melissococcus plutonius, while American foulbrood (AFB) is caused by Paenibacillus larvae. The relatively harmless European foulbrood is also known as benign foulbrood or "sour brood" due to the acidic smell it produces. In contrast, American foulbrood is referred to as malignant foulbrood and is reportable in Germany and Austria, as well as mandatory to report in Switzerland. As a preventive measure, any beekeeper can have their bee colonies inspected for American foulbrood by an officially appointed bee expert at any time. The most sensible time for this inspection is in the spring before the formation of splits.