ASSOCIATION OF PROKARYOTES WITH SYMPTOMATIC APPEARANCE OF WITHERING SYNDROME IN BLACK ABALONE HALIOTIS-CRACHERODII

Withering syndrome (WS) is an epizootic fatal wasting disease that is devastating California Channel Island populations of black abalone Hal iotis cracherodii. Our studies suggest a strong pathogen-disease assoc iation. The pathogen is an intracellular prokaryote that infects epith elial cells lining the gut and enzyme secreting cells of the digestive diverticula. It multiplies by binary fission in round to oval, basoph ilic, membrane-bound colonies teeming in the cytoplasm. Infection of t he digestive diverticula is accompanied by a complete loss of digestiv e enzyme granules and metaplasia of enzyme secretory cells to a morpho logy similar to epithelium lining the gut. Extensive infection of dige stive diverticular cells and the resultant deficiency in digestive enz ymes correlates to the degree of pedal muscle atrophy and the severity of signs associated with WS. Electron microscopically the intracellul ar pathogen is a rod-shaped, ribosome-rich, gram-negative, prokaryote with a trilaminar cell wall consistent with the order Rickettsiales. M icrobiological and protozoological methods produced no patterns that i mplicated other types of microbes. Chemical analysis of tissue from an imals from a population with WS did not support an association between WS and environmental pollutant exposure to polycyclic aromatic hydroc arbons, polychlorinated biphenyls, or chlorinated pesticides. (C) 1995 Academic Press, Inc.