Epizootic ulcerative syndrome: its aetiology and some epizootic characteristics.

摘要

Since epizootic ulcerative syndrome (EUS) first appeared in eastern India in 1988, a total of 547 fishes (Labeo rohita, L. kalbasu, L. bata, Catla catla, Cirrhinus mrigala, Barbus ticto, Puntius japonicus, Hypophthalmichthys molitrix, Cyprinus carpio, Ctenopharyngodon idella, Channa punctatus, Channa striatus, Anabus testudineus, Clarias batrachus and Heteropneustes fossilis) affected by EUS was collected from different parts of West Bengal, India, during 1997-1999 and examined for the presence of the probable aetiological agent, the chemoautotrophic nocardioform (CAN) bacteria, from the superficial and deep tissue lesions. The organisms did not grow on any common or conventional culture media like the nutrient or blood agar and Lowenstein Jensen or medium 199, but were successfully grown on media containing simple sources of carbon and nitrogen only. The actinomyceteocardioform isolates were acid-fast rods, which gave positive reaction with DOPA-oxidase, catalase, gelatinase and urease. The characteristic macrophage granuloma surrounding their mycelia appeared to be consistent with actinomycetic pathogenicity. The normal or healthy control fishes did not reveal these features. EUS poses not only a financial problem but is also a potential health hazard to man.