Pathogenicity of Spiroplasma apis and other spiroplasmas for honey-bees in southwestern France.

The haemolymph of honey-bees affected by a May disease-like disorder in southwestern France contained numerous spiroplasmas. Further characterization of the organisms and pathogenicity assays showed that the causal agent of the disease was a spiroplasma belonging to group IV. The name Spiroplasma apis was given to the reference strain B31 (ATCC 33834), one of the numerous similar isolates cultured from May-disease-affected bees. Spiroplasma isolates related to S. apis could be grown from the surface of flowers collected within the area visited by bees from the diseased hives. Several other strains belonging to group IV spiroplasmas were also isolated from the surface of flowers growing in southwestern France. In the same area, we also isolated, from pools of apparently healthy honey-bees and from the surface of a tulip tree flower, spiroplasma strains belonging to group I-2. One of these strains was shown to be pathogenic when introduced into adult bees by injection or food ingestion.