Abstract
From August to September in 1977, an epizootic occurred among cultured freshwater shrimp Palaemon paucidence in Okayama Prefecture. As the typical symptom of the disease, reddish brown spot was observed on the abdominal segment of shrimp. A vibrio (Vibrio sp.) was purely isolated from diseased specimens, and besides, most of the diseased shrimp were infested with parasitic isopod Tachea chinensis.
The pathogenicity of this vibrio was demonstrated by stab-inoculation to the muscle of shrimp or addition to rearing water of isopod-infested shrimp. However, isopod-free shrimp were not infected with the vibrio by the addition method. From these results, this isopod seemed to play an important role in this vibriosis of shrimp.
