Systematic granulomas caused by a rickettsia‐like organism in Nile tilapia, Oreochronuis niloticus (L.), from southern Taiwan

摘要: . A rickettsia-like organism was observed in diseased Nile tilapia, Oreochronuis niloticus (L.), from southern Taiwan. Most affected fish were pale and lethargic with haemorrhages ulcers on the skin. The most significant gross pathological changes varying degrees of ascites, enlargement spleen, kidney liver. Marked white nodules (as ring-shaped foci), size, found these organs. Gram-negative, (RLO) frequently appeared as inclusions or within host cell intra-cytoplasmic vacuoles. Fibrin thrombi, perivascular necrosis, chronic inflammatory cells hypertrophy RLO-laden characteristic disease. White induced experimental similar to naturally infected cases RLOs reisolated tissue culture using a CHSE-214 line. This provides evidence that systemic granulomas tilapia caused by RLOs.