SHRIMP DISEASES AND CURRENT DIAGNOSTIC METHODS

In less than 30 yr, the penaeid shrimp culture industries of the world developed from their experimental beginnings into major industries pr oviding hundreds of thousands of jobs, billions of U.S. dollars in rev enue, and augmentation of the world's food supply with a high value cr op. Concomitant with the growth of the shrimp culture industry has bee n the recognition of the ever increasing importance of disease, especi ally those caused by infectious agents. Major epizootics have plagued the world's shrimp culture industries. The most important diseases of cultured penaeid shrimp have had viral or bacterial etiologies, but a few important diseases have fungal and protozoan agents as their cause . Diagnostic methods for these pathogens include the traditional metho ds of morphological pathology (direct light microscopy, histopathology , electron microscopy), enhancement and bioassay methods, traditional microbiology, and the application of serological methods. While tissue culture is considered to be a standard tool in medical and veterinary diagnostic labs, it has never been developed as a useable, routine di agnostic tool for shrimp pathogens. The need for rapid, sensitive diag nostic methods led to the application of modern biotechnology to penae id shrimp disease. The industry now has modern diagnostic genomic prob es with nonradioactive labels for viral pathogens like IHHNV, HPV, TSV , WSSV, MBV, and BP. Additional genomic probes for viruses, for bacter ial pathogens like NHP and certain Vibrio spp., and Microsporidia have also been developed. Highly sensitive detection methods for some path ogens that employ DNA amplification methods based on the polymerase ch ain reaction (PCR) now exist, and more PCR methods are being developed for additional agents. These advanced molecular methods promise to pr ovide badly needed diagnostic and research tools to an industry reelin g from catastrophic epizootics and which must become poised to go on w ith the next phase of its development as an industry that must be bett er able to understand and manage disease. (C) 1998 Elsevier Science B. V. All rights reserved.