Virus-like particles detected in postlarvae of abalone (Haliotis diversicolor supertexta Lischke) potentially associated with mass mortalities

Abstract

Mass mortalities among cultured postlarvae of abalone, Haliotis diversicolor supertexta Lischke of between 10 and 30 days post fertilization, characterized by a white appearance and falling of the diatom films on which they grow, has occurred since 2002 on the south coast of China, including Taiwan. However, its causes remain debated. In this paper, we reported our latest findings on two different types of virus-like particles that are potentially associated with mass mortalities of postlarvae of abalone. Fourteen-day-old moribund postlarvae collected during an outbreak of postlarval disease in Shenzhen, China on November 10th, 2010 were examined by transmission electron microscopy. Besides showing severe damages in the postlarval tissues, two different types of virus-like particles were detected. These two virus-like particles were detected within both nuclei and cytoplasms of diseased abalone tissues. As they were detected in the diseased postlarval tissues, it is therefore suggested that they were potentially pathogens for postlarvae in that particular outbreak.