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White Spot Syndrome Virus (white + spot_syndrome_virus)
Selected AbstractsA Profound Effect of Hyperthermia on Survival of Litopenaeus vannamei Juveniles Infected with White Spot Syndrome VirusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2001Oscar M. Vidal This study was conducted to examine the effect of increasing seawater temperature on White Spot Syndrome Virus (WSSV) infection in juvenile Pacific White shrimp (Litopenaeus vannamei). Infection by WSSV was achieved using two methods, intramuscular injection and per os (oral) administration. Forty injected and 20 per os infected animals were kept in heated tanks at 32.3 ± 0.8 C, and the same number of WSSV infected animals were maintained in tanks at ambient temperature (25.8 ± 0.7 C). Despite the route of exposure, there were no survivors among the animals kept at ambient temperature; whereas, in heated tanks the survival of the WSSV infected juvenile shrimp was always above 80%, suggesting the existence of a beneficial effect from hyperthermia that mitigated the progression of WSSV disease. Moreover, this beneficial effect was not attributable to viral inactivation. Infected animals kept at 32 C had histologically detectable lymphoid organ spheroids suggestive of a chronic viral infection but were PCR negative (hemolymph) for WSSV. These findings might be related to low viral replication in WSSV-infected shrimp held at the higher environmental temperature. When the WSSV-infected shrimp were transferred from 32 C to ambient temperature, the mortality from WSSV ensued and was always 100%. Although the mechanism related to the beneficial effect of heating was not determined, our results indicate that increasing the water temperature modifies dramatically the natural history of the WSSV disease and the survival curves of WSSV-infected juvenile Pacific White shrimp. [source] A simple method for purifying the White Spot Syndrome Virus using ultrafiltrationAQUACULTURE RESEARCH, Issue 6 2009Martina Hilda Gracia-Valenzuela Abstract A very simple and efficient method was developed for isolating intact White Spot Syndrome Virus (WSSV) particles from infected Litopenaeus vannamei tissue. No density gradient centrifugation, ultracentrifugation or protease inhibitors were required for the purification of intact WSSV virions using microfilters (100 kDa cut-off) combined with several steps of conventional centrifugation procedures. A mortality assay was run using healthy shrimp to prove that the virions obtained were infective. The concentrated viral preparations were further studied using polyacrylamide gel electrophoresis (PAGE). At least five distinct protein bands were detected when intact purified WSSV virions were found by sodium dodecyl sulphate-PAGE, followed by Coomassie Brilliant R-250 staining. The estimated molecular weights of these proteins were 23, 24, 29, 32 and 42-kDa, which could correspond to viral protein. Using this method, the virus does not lose its ability to infect healthy shrimp. [source] Three tetraspanins from Chinese shrimp, Fenneropenaeus chinensis, may play important roles in WSSV infectionJOURNAL OF FISH DISEASES, Issue 1 2010B Wang Abstract Three members of the tetraspanin/TM4SF superfamily were cloned from Chinese shrimp, Fenneropenaeus chinensis. The deduced amino acid sequences of the three proteins have typical motifs of the tetraspanin/TM4SF superfamily. Phylogenetic analysis of the proteins, together with the known tetraspanins of invertebrates and vertebrates, revealed that they belong to different tetraspanin subfamilies: CD9, CD63 and tetraspanin-3. The three cloned genes of CD9, CD63 and tetraspanin-3 showed apparently different tissue distributions. The CD9 gene (FcCD9) was specifically expressed in the hepatopancreas. While for the CD63 gene (FcCD63), the highest expression was detected in nerves, epidermis and heart, with low expression in haemocytes, ovary, gill, hepatopancreas and stomach and no expression in intestine, muscle and lymphoid organ. Compared with FcCD9 and FcCD63, the tetraspanin-3 gene (FcTetraspanin-3) was more broadly expressed and its highest expression was detected in the intestine. Its expression in nerves was lower than in the intestine, but was higher than in other tissues. Expression in haemocytes, ovary and muscle was much lower than in other tissues. The expression profiles of FcCD9, FcCD63 and FcTetraspanin-3 in different tissues, including haemocytes, lymphoid organ and hepatopancreas, were compared by real-time PCR when shrimp were challenged by live white spot syndrome virus (WSSV) and heat-inactivated WSSV. All three tetraspanins were markedly up-regulated in the live WSSV-challenged shrimp tissues. The data suggested that the three cloned members of TM4SF superfamily in Chinese shrimp may play a key role in the route of WSSV infection. [source] Pre-exposure to infectious hypodermal and haematopoietic necrosis virus or to inactivated white spot syndrome virus (WSSV) confers protection against WSSV in Penaeus vannamei (Boone) post-larvaeJOURNAL OF FISH DISEASES, Issue 10 2006J Melena Abstract Larvae and post-larvae of Penaeus vannamei (Boone) were submitted to primary challenge with infectious hypodermal and haematopoietic necrosis virus (IHHNV) or formalin-inactivated white spot syndrome virus (WSSV). Survival rate and viral load were evaluated after secondary per os challenge with WSSV at post-larval stage 45 (PL45). Only shrimp treated with inactivated WSSV at PL35 or with IHHNV infection at nauplius 5, zoea 1 and PL22 were alive (4.7% and 4%, respectively) at 10 days post-infection (p.i.). Moreover, at 9 days p.i. there was 100% mortality in all remaining treatments, while there was 94% mortality in shrimp treated with inactivated WSSV at PL35 and 95% mortality in shrimp previously treated with IHHNV at N5, Z1 and PL22. Based on viral genome copy quantification by real-time PCR, surviving shrimp previously challenged with IHHNV at PL22 contained the lowest load of WSSV (0,1 × 103 copies ,g,1 of DNA). In addition, surviving shrimp previously exposed to inactivated WSSV at PL35 also contained few WSSV (0,2 × 103 copies ,g,1 of DNA). Consequently, pre-exposure to either IHHNV or inactivated WSSV resulted in slower WSSV replication and delayed mortality. This evidence suggests a protective role of IHHNV as an interfering virus, while protection obtained by inactivated WSSV might result from non-specific antiviral immune response. [source] Apoptosis does not play an important role in the resistance of ,immune'Penaeus japonicus against white spot syndrome virusJOURNAL OF FISH DISEASES, Issue 1 2004J L Wu Abstract We previously demonstrated that kuruma shrimp, Penaeus japonicus, exposed to white spot syndrome virus (WSSV) became resistant (,immune' shrimp) to subsequent challenge with the virus. The present study investigated the role of apoptosis in the ,immune' shrimp during a secondary challenge with WSSV. When naive kuruma shrimp were intramuscularly injected with WSSV at a high or low dose, apoptosis was often detected by TUNEL assay in the lymphoid organ (LO), mainly in the early stage of the infection. A significantly higher incidence of apoptosis was observed in the LO of the shrimp injected with the high dose of WSSV (cumulative mortality: 100%) than in the shrimp injected with the low dose (cumulative mortality: 0%). When ,immune' and naive shrimp were injected with an equal dose of WSSV, the incidence of apoptosis was significantly lower in the ,immune' shrimp than in the naive shrimp. This difference is assumed to result from a substantial reduction of the virus by humoral neutralizing factor in the ,immune' shrimp. These results suggest that apoptosis is not a principal protective factor in ,immune' shrimp. [source] Larvae and early post-larvae of Penaeus monodon (Fabricius) experimentally infected with white spot syndrome virus (WSSV) show no significant mortalityJOURNAL OF FISH DISEASES, Issue 7 2003K Yoganandhan Abstract The pathogenicity of white spot syndrome virus (WSSV) was tested with different developmental stages of Penaeus monodon, i.e. nauplius, protozoeae, mysis, early post-larvae (PL1-10), late post-larvae (PL11-20) and juveniles. WSSV challenge was done by immersion and oral routes. No disease occurred in the larvae and early post-larvae but they were positive for WSSV by nested polymerase chain reaction (PCR) assay. Significant mortality was observed in late post-larvae and juveniles and both single and nested PCR assays gave positive results with these samples. The results demonstrated that WSSV virulence in P. monodon increases with advancing stages of development and that WSSV infection does not result in disease for larvae and post-larvae younger than PL10. [source] Experimental susceptibility of different life-stages of the giant freshwater prawn, Macrobrachium rosenbergii (de Man), to white spot syndrome virus (WSSV)JOURNAL OF FISH DISEASES, Issue 4 2002R B Pramod Kiran Studies were conducted by injecting/feeding white spot syndrome virus (WSSV) derived from infected shrimp, Penaeus monodon (Fabricius), to different life-stages, namely post-larvae, juveniles, sub-adults and adults of Macrobrachium rosenbergii (de Man). The disease was also induced in brood stock, and the eggs and larvae derived from these animals were subsequently tested for WSSV infection. All the stages except egg used for the experiment were found WSSV positive in histopathology, cross infection bioassay and polymerase chain reaction (PCR) analysis. Experimentally infected post-larvae and juveniles showed a high percentage of mortality and an increased rate of cannibalism. The cumulative mortality in post-larvae was up to 28%; with 28,40% cannibalism resulting in a maximum loss of up to 68%. In juveniles, observed mortality and cannibalism were 10,20% and 6.7,30.0%, respectively, and the maximum loss recorded was 50%. In sub-adults, mortality ranged from 2.8 to 6.7%, cannibalism was up to 20% and the total loss was up to 26.7%. Sub-adults and adults were found to be more tolerant to the infection as evidenced by the mortality pattern. A nested (two-step) PCR resulted in a 570-bp product specific to WSSV in all stages, except the eggs. [source] Characterization and application of monoclonal antibodies against white spot syndrome virusJOURNAL OF FISH DISEASES, Issue 3 2001Three hybridoma clones secreting monoclonal antibodies (MAbs) were produced from mouse myeloma and spleen cells immunized with white spot syndrome virus (WSSV) isolated and purified from Penaeus monodon (Fabricius), collected from north-eastern Taiwan. By sodium dodecyl sulphate,polyacrylamide gel electrophoresis (SDS,PAGE), the protein profile of this isolate contained four major proteins with sizes of approximately 35 (VP35), 28 (VP28), 24 (VP24), and 19 kDa (VP19). Western blot analysis revealed that two MAbs (1D7 and 6E1) recognized epitopes on VP28 and one MAb (3E8) recognized an epitope on VP19. The MAb 6E1 isotyped to the IgG1 class was used in both an indirect immunofluorescence assay (IFA) and in an immunochemical staining protocol for successful identification and localization of WSSV in infected shrimp tissues. Antigenic similarity of isolates from Indonesia and Malaysia to the Taiwan isolate was illustrated by IFA with MAb 6E1. A MAb (2F6) which bound specifically to two shrimp proteins, 75 and 72 kDa, and reacted to the healthy and non-target tissues of WSSV in infected shrimp, such as hepatopancreas, is also described here and shows the necessity for specific identification of antibodies. [source] A Microsatellite DNA Marker Developed for Identifying Disease-resistant Population of Giant Black Tiger Shrimp, Penaeus monodonJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2009Kuntal Mukherjee White spot disease caused by white spot syndrome virus (WSSV) poses major problems that result in huge economic losses each year in shrimp aquaculture throughout the world. In the present study, microsatellite-based DNA fingerprints have been compared between naturally occurring WSSV disease-resistant and susceptible populations of giant black tiger shrimp, Penaeus monodon, to find DNA markers. For the first time, we report here a microsatellite locus, which, after amplification by polymerase chain reaction, provides a highly statistically significant DNA fingerprint of 71 bp, only in disease susceptible populations but not in disease-resistant shrimp populations, whereas a 317 bp band is common in both. The absence of the former DNA marker will be very useful to identify disease-resistant broodstock of P. monodon for marker-assisted selection in breeding programs to generate disease-free shrimps (P. monodon) in the aquaculture industry. [source] Oral vaccination with envelope protein VP28 against white spot syndrome virus in Procambarus clarkii using Bacillus subtilis as delivery vehiclesLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2008L.L. Fu Abstract Aims:, To achieve high-level expression and secretion of active VP28 directed by a processing-efficient signal peptide in Bacillus subtilis WB600 and exploit the possibility of obtaining an oral vaccine against white spot syndrome virus (WSSV) using vegetative cells or spores as delivery vehicles. Methods and Results:, The polymerase chain reaction (PCR)-amplified vp28 gene was inserted into a shuttle expression vector with a novel signal peptide sequence. After electro-transformation, time-courses for recombinant VP28 (rVP28) secretion level in B. subtilis WB600 were analysed. Crayfish were divided into three groups subsequently challenged by 7-h immersion at different time points after vaccination. Subgroups including 20 inter-moult crayfish with an average weight of 15 g in triplicate were vaccinated by feeding coated food pellets with vegetative cells or spores for 20 days. Vaccination trials showed that rVP28 by spore delivery induced a higher resistance than using vegetative cells. Challenged at 14 days postvaccination, the relative per cent survival (RPS) values of groups of rVP28-bv and rVP28-bs was 51·7% and 78·3%, respectively. Conclusions:, The recombinant B. subtilis strain with the ability of high-level secretion of rVP28 can evoke protection of crayfish against WSSV by oral delivery. Significance and Impact of the Study:, Oral vaccination by the B. subtilis vehicle containing VP28 opens a new way for designing practical vaccines to control WSSV. [source] Effect of hot water extracts of brown seaweeds Sargassum spp. on growth and resistance to white spot syndrome virus in shrimp Penaeus monodon postlarvaeAQUACULTURE RESEARCH, Issue 10 2010Grasian Immanuel Abstract An experiment was conducted to evaluate the effect of a hot water extract of brown seaweeds Sargassum duplicatum and Sargassum wightii on the growth and white spot syndrome virus (WSSV) resistance in shrimp Penaeus monodon postlarvae (PL). Artemia nauplii (instar II) were enriched with both seaweed extracts at various concentrations (250, 500 and 750 mg L,1) and fed to the respective P. monodon (PL15,35) group for 20 days. A control group was also maintained without seaweed extract supplementation. The weight gain of the experimental groups was significantly higher (0.274,0.323 g) than the control group (0.261 g). Similarly, the specific growth rate was also significantly higher (16.27,17.06%) in the experimental groups than in the control group (16.03%). After 20 days of the feeding experiment, the shrimp PL were challenged with WSSV for 21 days. During the challenge test, the control shrimp displayed 100% mortality within 8 days. In contrast, the mortality percentage of the highest concentration (750 mg L,1) of seaweed extract enriched Artemia nauplii fed shrimp was 54,79%. Comparatively, low mortality was observed in S. wightii extract-enriched Artemia nauplii fed shrimp. The polymerase chain reaction analysis indicated the concentration-dependent infection of WSSV in P. monodon PL. [source] Comparison of defence ability against the white spot syndrome virus between Fenneropenaeus chinensis and Marsupenaeus japonicusAQUACULTURE RESEARCH, Issue 9 2010Guojian Jiang Abstract The defence ability of Fenneropenaeus chinensis and Marsupenaeus japonicus against the intrusion of the white spot syndrome virus (WSSV) was compared after injecting WSSV intramuscularly by recording cumulative mortality, diagnosing the virus and examining variations in immunological parameters including the total haemocyte counts (THCs), phagocytic percentage (PP), plasma protein concentration (PPC), phenoloxidase (PO) and nitric oxide synthase (NOS) activity. The results showed that the variations in the immunological parameters of F. chinensis and M. japonicus showed similar trends. The THCs of the two species decreased significantly postchallenge of WSSV. The virus was detected at 78 h in M. japonicus and at 42 h in F. chinensis after infection, which was in correlation with the accumulative mortality, and the variations in PO, PP, NOS and PPC in the two species. All shrimps of F. chinensis in the mortality experiment died within 66 h, much more quickly than M. japonicus, whose cumulative mortality reached 100% after 198 h. In conclusion, the immune system of M. japonicus has a stronger resistant ability to antagonize and endure the invasion of WSSV than that of F. chinensis. [source] Marine yeast diet confers better protection than its cell wall component (1-3)-,- d -glucan as an immunostimulant in Fenneropenaeus indicusAQUACULTURE RESEARCH, Issue 15 2009Thavarool Puthiyedathu Sajeevan Abstract A comparative study was performed to evaluate the immunostimulatory effect of yeast and yeast-derived glucan in white prawn Fenneropenaeus indicus (sub-adults of ,20 gm). Feed with a whole cell biomass of marine yeast Candida sake S165 (CSY) at a concentration of 10% (w/w) and another feed with 0.2% glucan of C. sake S165 (CSG) were used in the study. Fenneropenaeus indicus were fed with these diets for 40 days and subsequently challenged with the white spot syndrome virus (WSSV). Haematological parameters such as the total haemocyte count, phenoloxidase activity, superoxide anion (O2,) level, haemolymph peroxidase level and post-challenge survival against WSSV infection were determined to assess the immune status. In the present experiment, a higher immunity index and post-challenge survival were recorded in shrimps fed with the whole cell yeast diet. The better immunostimulatory performance of the whole cell yeast diet compared with the glucan diet could be attributed to the cellular constituents of yeast including the cell wall glucan, nucleotides, carotenoid pigments and vitamins. Here we observed that whole cell yeast performed better as an immunostimulant than the extracted cell wall glucans. Therefore, the use of yeast biomass in diets, rather than the yeast cell wall extract, glucan, would confer better protection against microbial infection besides reducing the cost of shrimp production. [source] Oral vaccination trials with crayfish, Procambarus clarkii, to induce resistance to the white spot syndrome virusAQUACULTURE RESEARCH, Issue 15 2009Fei Zhu Abstract The potential of oral vaccination against white spot syndrome virus (WSSV) in crayfish Procambarus clarkii was investigated. The protective effect of binary ethylenimine (BEI)-inactivated WSSV was tested by oral vaccination, followed by an oral challenge with WSSV. The crayfish fed with feed pellets coated with BEI-inactivated WSSV showed a resistance to WSSV on the seventh day post vaccination (dpv). The relative percentage survival values were 60%, 70% and 75% for the vaccinated once, twice and thrice with inactivated WSSV. Following an intramuscular injection experiment, no mortality was recorded in the inactivated WSSV group and the negative control at 17 days post challenge. The cumulative mortalities in the heated WSSV group and WSSV group were 100%. Shrimp that survived the WSSV challenge on the seventh day after cessation of oral vaccination were positive for the presence of WSSV by a polymerase chain reaction assay specific for WSSV. This result indicated that inactivated WSSV could protect crayfish against WSSV by oral delivery. [source] Probiotic microorganisms and antiviral plants reduce mortality and prevalence of WSSV in shrimp (Litopenaeus vannamei) cultured under laboratory conditionsAQUACULTURE RESEARCH, Issue 13 2009Viridiana Peraza-Gómez Abstract The protective effect of a probiotic mixture (PM) and antiviral plants, against the white spot syndrome virus (WSSV) in Litopenaeus vannamei, was evaluated in three experiments. The PM was composed of four lactic acid bacteria (LAB) and one yeast strain. The plant mixture was composed of Ocimum sanctum and commercial antiviral plants (VPH®, HSV®). Shrimp in each experiment (weighing 2.7±0.7, 11.5±1.3, 11.70±2.5 g) were cultured in 120-L plastic tanks and fed twice a day with commercial feed plus additives (plants or bacteria and yeast). Animals were monitored for the occurrence of WSSV by single-step and nested PCR. The PM and powdered antiviral plants added to the commercial feed showed an increase in survival and a decrease in the prevalence of WSSV in shrimp. The results showed that both the PM and the powdered antiviral plants can provide protection for shrimp against WSSV. [source] Virulence status, viral accommodation and structural protein profiles of white spot syndrome virus isolates in farmed Penaeus monodon from the southeast coast of IndiaAQUACULTURE RESEARCH, Issue 2 2009Victor Stalinraj Abstract The objective of this study was to investigate the reason for variation in the virulence of white spot syndrome virus (WSSV) from different shrimp farms in the Southeast coast of India. Six isolates of WSSV from farms experiencing outbreaks (virulent WSSV; vWSSV) and three isolates of WSSV from farms that had infected shrimps but no outbreaks (non-virulent WSSV; nvWSSV) were collected from different farms in the Southeast coast of India. The sampled animals were all positive for WSSV by first-step PCR. The viral isolates were compared using histopathology, electron microscopy, SDS-PAGE analysis of viral structural proteins, an in vivo infectivity experiment and sequence comparison of major structural protein VP28; there were no differences between isolates in these analyses. A significant observation was that the haemolymph protein profile of nvWSSV-infected shrimps showed three extra polypeptide bands at 41, 33 and 24 kDa that were not found in the haemolymph protein profile of vWSSV-infected shrimps. The data obtained in this study suggest that the observed difference in the virulence of WSSV may not be due to any change in the virus, rather it could be due to the shrimp defence system producing certain factors that help it to accommodate the virus without causing any mortality. [source] Experimental white spot syndrome virus challenge of juvenile Litopenaeus vannamei (Boone) at different salinitiesAQUACULTURE RESEARCH, Issue 15 2008I S Carbajal-Sánchez Abstract In recent years, the shrimp industry has turned to inland freshwater culture as one method to avoid problems such as the introduction of possible vectors of viral pathogens into seawater ponds. Our experiments evaluated susceptibility to white spot syndrome virus (WSSV) in Litopenaeus vannamei held under different salinity regimens. Juvenile L. vannamei that were conditioned at salinities of 35, 25, 15, 5 and 2 g L,1 were challenged with WSSV. In order to assess the severity of white spot disease, histological analysis and nested polymerase chain reaction (PCR) tests were carried out on the challenged shrimp every 4 h after 48 h post challenge. The results indicated that significantly more severe infections resulted at 15, than at other salinities. Mortality could not be compared due to the sampling design and because severe WSSV infections occurred in all test groups such that few shrimp remained alive in each challenged group at the end of the test. Despite this, the results suggest that salinity may affect the course and outcome of WSSV infections. [source] Expression, purification and crystallization of a novel nonstructural protein VP9 from white spot syndrome virusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 8 2006Yang Liu The nonstructural protein VP9 from white spot syndrome virus (WSSV) has been identified and expressed in Escherichia coli. To facilitate purification, a cleavable His6 tag was introduced at the N-terminus. The native protein was purified and crystallized by vapour diffusion against mother liquor containing 2,M sodium acetate, 100,mM MES pH 6.3, 25,mM cadmium sulfate and 3% glycerol. Crystals were obtained within 7,d and diffracted to 2.2,Å; they belonged to space group P212121, with unit-cell parameters a = 74.13, b = 78.21, c = 78.98,Å and four molecules in the asymmetric unit. The selenomethionine-labelled protein produced isomorphous crystals that diffracted to approximately 3.3,Å. [source] | ||||||||||