Since 1993, the White Spot Syndrome Virus (Wssv) disrasc occurted in China among cultured shrimps resulting in mass mortality. Eirootiological surveys trndertaken during the outbreak period of 1993-1994 indicated that all stages of peeus chitensts, P. uems and p. were infected. Conssquent bo the transport of contaminated shrlmp seedlings and seawaler, the diseasc sprcad all over the farrns. of china. The disease was more rapidly transmitted at lemeratures above 25℃, Challenge experiments showed the causative agent wss highly virulent, White sots appeared on the carqpace of both spon-taneous. and experimentally infected shrimps. Moribund shrimps contalned burbld hemolymph, hy-perticleg, in the gills, stomach, lymphold organ, and epidermal tissuc of the infected sherim. The virlons were sllghtly ovold with an envelope and avcragcd 350×150nm, nucleocapoids measurd 375×157nm. With discontinuous suceose gradient of 35,50 and 60% (W/v),the virus was separated from hemolymph of the infected shrimp. The estimated molecular weight of genomk DNA was 237Kb with EcoR I,247Kb with hind Ⅲ and 241kb with Pst1. A total of 9 hybridoma colones secrting monoclonal antibodies (MAbs) were produced from mouse myelonu and spleen cells lmnunlzed with wssv. the immunofluorescence assay of gill tissue showed that the mabs reacted with discascd but not with healthy shrimp. The Mabs belonged to IgG1, IgG2b subclass and IgM class, all with kappa light Lmmuno-electron-mderoseopy with colloidal gold markcr showcd the prcsence of 5 Mabs epitopes on the envelope and one on the capsid of the virus Baculoviral mid-gut gland necrosis showed the specltlclty of the MAbs produced, for diagnosis 5 different methods were selected. Using Kimura Primers for PcR, or Mabs for immunoblot, ELISA or FAT method im sith hybridiztion was carried out to show the gene, All these methods detected WSSV in the organ ramples of the diseased shrimp but not in helthy ons.

d development of lymphocystis cells in flounder Paralichthys olivaceus, and some his- tochemical features are studied using light and electron microscopy and histochemical methods. ibrob-lasts engulf virus particles forming phagocytosis vacuole in the cytoplasm. The infected cells proliferateand turn round and hypertrophied; basophilic inclusion bodies, Feulgen-positive, are present in the cyto-plasm, and a hyaline capsule, containing acid ploysaccharide and protein, appears outside cell mem-brane. The mature lymphocystis cells possess numerous virus particles (200～220nm in diameter with a central core 120～140nm) and high electron-dense inclusions with budding virions at the surface in the cytoplasm, and show margination of chromatin. Moderate electron density particles (70～80nm in diame-ter) fill out perinuclear cisterna and arrange in crystalloid arrays in nucleus, liberated into the cytoplasm by rupture of nuclear membrane. No virus particles are observed in nucleus. Therefore, inclusion bodies are the sites of virus assembly and maturity, while replication processes of lymphocystis virus are involved in both nuclear and cytoplasmic phases. Besides, strongly basophilic link2like structures are present be-tween adjacent cells or through connective tissue, and virus particles are observed in somewhere of the capsule, thus where may be the spread route of virus from one cell to another or to the environment. The senile lymphocystis cells release virus by the rupture of cells.

Nine bybaldoma clcmes secreting monoclonal antlbodies (Mabs) were peodineed from monse myeloma and spleen cells immunized with while spot syndrome virus (WSSV), An imdirect pathogen of ealtured penaeld shrimp Asin since 1993 Am imdirect immonoftucrescence essay was standardixed to evaluate the usefulness of the Mabs for rapid diagmostic techniques to idemlify WSSV and for further mudy of this virus. tsoryping revealed that the brabs were of immunoglobulin G (IgG) and immunaoglobulin M (IgG)class. All with kappoa light chains. Four Mabs were examlned by using immune elecron microssopy and colloidal gold as a markee, Three Mabs recogniged epitoped on the envelope of the virus and one Mab recognleed an eplnope on the copsld. The epitopes on the envelope of the virus and one Mab recognleed an eplanope on the copsld, The specilieity of the Mabs to WSSV was eltermined by a lack of recktivity with vissue comtuingg a second pemenld shrimp agens. The baculovirul mld*gat gland necrosls virus.

White Spot Syndrome Virus (WSSV) was purified from hemolymph of infected shrimp. After nucleic acid extraction from the purified virus particles, EcoRI-digested fragments of the WSSV genome were cloned; three of these fragments were used as non-radioactive probes labeled with DIG-11-dUTP. The probes hybridized in situ, with sections located in the nuclei of all WSSV2infected tissues. The virus was de-tected in the gill, stomach, epidermis, and connective tissue and so on, but not detected in healthy shrimp tissues and epithelial cells of hepatopancreatic tubules of diseased shrimp.

Haemocyte types of the scallop (Chlamys farreri) were identified by Giemsa stain and flow cytometry (FCM). Additionally, the activities of peroxidase (POD), phenoloxidase (PO) and alkaline phosphatase (ALP) in haemocytes were analysed by immunocytochemical and biochemical methods. The results indicate that there were two types of haemocytes in the scallop, hyalinocytes and granulocytes, and that POD, PO and ALP were more abundant and more active in granulocytes than in hyalinocytes.