Two major research themes have been addressed. The first is the identification of novel pathogens and the development of disease control methods for fish and shellfish. In aquaculture farms, mortality caused by unidentified diseases is often observed. The causative factors are quite complex including deterioration of the environment, nutritional disorders, and outbreak of infectious diseases. With recent advances in aquaculture technology, the targeted species for aquaculture have expanded, and new infectious diseases have been reported one after another. Therefore, we are exploring the pathogens using a comprehensive genetics approach to develop the diagnosis methods and control the diseases. Second, we are also studying the unique immune system in shrimp. As invertebrates, shrimp have no adaptive immune system like vertebrates. However, they show some resistance to re-infection of particular pathogen, like a phenomenon known as “immunological memory”. We hope to elucidate the mechanism of this phenomenon and propose new disease control measures to improve productivity.