Detection and identification of Melissococcus plutonius in stingless bees (Apidae: Meliponini) from Brazil.

European Foulbrood (EFB), caused by the bacterium Melissococcus plutonius, primarily affects young bee larvae, which may lead to colony decline. Once thought to affect only western honey bee Apis mellifera, EFB is now spreading to other bee species in Brazil. We identified EFB and detected M. plutonius in 10 species of stingless bees (Meliponini, Apidae) across the States of Minas Gerais, São Paulo, and Santa Catarina, including new cases in Partamona helleri, Plebeia droryana, Melipona quadrifasciata quadrifasciata, Nannotrigona cfr. testaceicornis, and Tetragonisca angustula. The bacterium M. plutonius was also detected in larval food, honey, pollen, and other materials from the colonies of some stingless bee species, as well as in A. mellifera honey from colonies adjacent to stingless bee colonies, suggesting the rearing environment aids bacterial transmission. Our study highlights the need for ongoing surveillance and strict management practices, as no effective treatment exists in Brazil.