Amoeba Dysentery
Krankheiten
Amoeba dysentery is caused by the single-celled organism Malpighamoeba mellificae.
Amoeba dysentery is caused by the single-celled organism Malpighamoeba mellificae. It migrates through the gut into the Malpighian tubules, which perform the function of the kidney in bees, and multiplies there. The fine tubules become blocked, swell, and lose their function. Uric acid is deposited as a milky white paste, the ion balance is disrupted, and the bee develops diarrhea.
The disease is transmitted via feces. Reproductive stages are excreted, and cleaning bees in particular become infected when defecation has occurred inside the hive. Persistent forms survive for a long time outside the bee, for example on soiled frames. Without thorough cleaning and disinfection, further colonies become infected.
In the colony, amoeba dysentery cannot be distinguished from Nosema disease. Both show fecal spots on combs, frames, and the flight front, crawling bees in front of the entrance, and increased die-off, and both occur predominantly in spring. Only microscopic examination of a Malpighian tubule provides certainty. The amoeba's cysts are rounder than the spores of Nosema disease. In non-contagious dysentery, by contrast, the Malpighian tubules are unremarkable.
Amoeba dysentery is a factor-related disease and frequently occurs together with Nosema disease. It is favored by rainy, nectar-poor summers and long winters. The pathogen develops particularly well in the long-lived winter bees. The most effective self-healing is therefore the rapid generational turnover in spring. In Central Europe, diarrheal diseases overall are only rarely the cause of colony losses.