The relationship between pathogenic infecion status and motality of the scallop Chlamys farreri

Pathogenic infect ion status of the cultured scallop Chlamys farreri was invest igated from May to November 2001. With negative staining technique, virus and Rickettisia-like organisms ( RLO) were detected in tissue extract of samples. Infection rate of virus ranged from 80% to 100%. The highest infection intensity of virus is found in July and August when acute death of Chlamys farreri occurred. Similar results acquired after Chlamys f arreri was injected with virus. The present work demonstrated that infection rates and intensity of RLO were not signif icantly different for cultured and artificial infected Chlamys farreri . The observation in 98 specimens conf irmed that the direct pathogen of explosive epidemic disease of Chlamys farreri was possibly a kind of spherical RNA virus with envelope and spike in cytoplasm. Which was found in a large amount during who le culture period and throughout all part s of the host .