Entity

Time filter

Source Type


Cheng L.,Graduate Institute of Animal Vaccine | Lin W.H.,Pingtung Hsien Livestock Disease Control Center | Wang P.C.,National Pingtung University of Science and Technology | Hsu J.P.,Pingtung Hsien Livestock Disease Control Center | Chen S.C.,Graduate Institute of Animal Vaccine
Diseases of Aquatic Organisms | Year: 2011

Taura syndrome virus (TSV) has spread worldwide, causing significant economiclosses since Taura syndrome was first described in Ecuador in 1992. To determine the prevalenceand impact of TSV infection on the shrimp farming industry in Taiwan, Pacific white shrimpLitopenaeus vannamei B. were collected from 220 farms between 2004 and 2006 for viral detectionby reverse transcription polymerase chain reaction. Data showed that the overall TSV prevalencerate was 20% (43/220 farms). Comparing shrimp growth stages, TSV prevalence rates were4% for postlarvae, 24% for juveniles, 24% for subadults, 32% for adults, and 5% for brooders.Among TSV-positive farms, average infection incidence was 35% in postlarvae farms, 55% injuvenile farms, 39% in subadult farms, 31% in adult farms, and 20% in brooder farms. Notably,TSV was also detected in Exopalaemon orientis H. from 1 of 10 farms. Tail fans and appendageshad red pigmentation, which is characteristic of TSV infection. Of shrimp with pathologicallesions, 100% had lesions on tail fans, 88% on appendages, and 80% in gills. Sequence comparisonusing the TSV VP1 (structural protein) gene showed that 9 isolates from the farms had 92.3 to99.5% nucleotide sequence identity with strains in the GenBank database from Taiwan(AF406789 and AY355310) and Venezuela (DQ212790). This is the first broad epidemiologicalstudy of TSV infection in L. vannamei in Taiwan. © Inter-Research 2011. Source


Cheng L.,National Pingtung University of Science and Technology | Chen C.-Y.,National Pingtung University of Science and Technology | Tsai M.-A.,National Pingtung University of Science and Technology | Wang P.-C.,National Pingtung University of Science and Technology | And 4 more authors.
Journal of Fish Diseases | Year: 2011

Koi herpesvirus (KHV) poses a significant threat to cultured koi and common carp, both Cyprinus carpio L. Since the first reported case in Israel in 1998, KHV has rapidly spread worldwide. This study investigates the spread of KHV to Taiwan by collecting 49 cases of suspected common carp and koi infections from 2003 to 2005 for analysis. Clinical signs included lethargy, anorexia, increased respiratory movements and uncoordinated swimming. Hyperaemia, haemorrhage on body surface and necrotic gill filaments were recorded. Gill epithelial hyperplasia, necrosis and eosinophilic intranuclear inclusion bodies were observed by histological examination, while virions were detected using transmission electron microscopy. By detecting the presence of the KHV thymidine kinase (TK) gene and the KHV 9/5 gene using polymerase chain reaction (PCR), 37 cases were identified as KHV-positive, and the cumulative mortality of infected fish was 70-100%. Positive cases showed identical sequences for the genes analysed, implying that they were of the same origin. For the KHV 9/5 gene sequence, these cases exhibited 100% identity with the Japanese strain (TUMST1, accession number AP008984) and 99% identity with the Israeli (KHV-I, DQ177346) and US (KHV-U, DQ657948) strains. Additionally, a loop-mediated isothermal amplification (LAMP) assay was performed and found to be more sensitive than PCR tests, suggesting its potential use as a rapid diagnostic method for KHV. This is the first epidemiological study of KHV infection in cultured common carp and koi in Taiwan. © 2011 Blackwell Publishing Ltd. Source


Cheng L.,National Pingtung University of Science and Technology | Lin W.-H.,National Pingtung University of Science and Technology | Lin W.-H.,Pingtung Hsien Livestock Disease Control Center | Wang P.-C.,National Pingtung University of Science and Technology | And 3 more authors.
Journal of Fish Diseases | Year: 2013

White spot syndrome virus (WSSV) has caused significant losses in shrimp farms worldwide. Between 2004 and 2006, Pacific white shrimp Litopenaeus vannamei (Boone) were collected from 220 farms in Taiwan to determine the prevalence and impact of WSSV infection on the shrimp farm industry. Polymerase chain reaction (PCR) analysis detected WSSV in shrimp from 26% of farms. Juvenile shrimp farms had the highest infection levels (38%; 19/50 farms) and brooder shrimp farms had the lowest (5%; one of 20 farms). The average extent of infection at each farm was as follows for WSSV-positive farms: post-larvae farms, 71%; juvenile farms, 61%; subadult farms, 62%; adult farms, 49%; and brooder farms, 40%. Characteristic white spots, hypertrophied nuclei and basophilic viral inclusion bodies were found in the epithelia of gills and tail fans, appendages, cephalothorax and hepatopancreas, and virions of WSSV were observed. Of shrimp that had WSSV lesions, 100% had lesions on the cephalothorax, 96% in gills and tail fans, 91% on appendages and 17% in the hepatopancreas. WSSV was also detected in copepoda and crustaceans from the shrimp farms. Sequence comparison using the pms146 gene fragment of WSSV showed that isolates from the farms had 99.7-100% nucleotide sequence identity with four strains in the GenBank database - China (AF332093), Taiwan (AF440570 and U50923) and Thailand (AF369029). This is the first broad study of WSSV infection in L. vannamei in Taiwan. © 2013 John Wiley & Sons Ltd. Source

Discover hidden collaborations