Koi herpesvirus epizootic in cultured carp and koi, Cyprinus carpio L., in Taiwan.

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.

Nocardia seriolae infection in the three striped tigerfish, Terapon jarbua (Forsskål).

An epizootic in pond cultured three striped tigerfish, Terapon jarbua, in Taiwan was caused by Nocardia seriolae. Diseased fish first showed clinical signs and mortalities in February and March 2003. The cumulative mortality within 2 months was 2.4% (1200 of 50 000) and affected fish were 7 months old with total lengths from 18 to 25 cm. Most affected fish were pale and lethargic with haemorrhages and ulcers on the skin. The most significant gross pathological changes were varying degrees of ascites and enlargement of the spleen, kidney and liver. Obvious white nodules, varying in size, were found in these organs. Bacteria were either coccal or filamentous in appearance, with bead-like forms. Isolates from diseased fish were characterized using the API ZYM (Analytical profile index; Bio Mérieux, France) systems and conventional tests and identified as Nocardia sp. The isolate was designated NS127 and was confirmed as N. seriolae by a polymerase chain reaction assay that gave the expected specific 432 bp amplicon. In addition, its 16S rDNA sequence gave 100% sequence identity with N. seriolae. A partial sequence of the 16S rRNA gene, heat shock protein gene and RNA polymerase gene (rpo B) of NS127 and the type strain of N. seriolae BCRC 13745 formed a monophyletic clade with a high sequence similarity and bootstrap value of 99.9%. White nodules induced in experimental fish were similar to naturally infected cases and N. seriolae was re-isolated on brain heart infusion agar. This is the first report of N. seriolae-infection in three striped tigerfish in aquaculture.

Naturally-occurring adenovirus-associated gastrointestinal lesions in Coturnix (Coturnix coturnix) quail.

Farm-reared Coturnix quail less than 3 weeks old showed depression, ruffled feathers, diarrhoea and high mortality. Histological examination revealed basophilic intranuclear inclusion bodies mainly in the digestive tract, and rarely in the liver, kidney, nasal epithelium, conjunctiva and columnar epithelial cells within the mucosa of the bursa of Fabricius. The inclusions were more numerous in the caeca than in the small intestine. Ultrastructurally, they contained many adenovirus-like particles approximately 60 nm in diameter. This is the first evidence of adenoviral inclusions in the glandular epithelium of the gizzard, conjunctiva, plical epithelium of bursa of Fabricius, and mucosal epithelium of small and large intestines in Coturnix quail.