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In the past decades, the aquaculture industry made great progress in China, which contributes more than 70% yield of the world's farmed fish. Along with the rapid growth of fish production, increased emergence and outbreak of numbers of diseases pose harm to the aquaculture industry and food safety. From the efficient, safe, environmental and ethical aspects, vaccines is definitely the most appropriate and focused method to control different kinds of fish diseases. In China, researchers have done huge works on the fish vaccines, and so far six domestic aquatic vaccine products along with one imported aquatic vaccine have obtained the national veterinary medicine certificate. More critically, some new vaccines have also entered the field experiment stage and showed broad market prospects. In the present review, authors summarize seven aquatic vaccines, including the live vaccine against grass carp hemorrhagic disease, the inactivated vaccine against Aeromonas hydrophila sepsis in fish, the live vaccine against Edwardsiella tarda in turbot, the anti-idiotypic antibody vaccine against Vibrio alginolyticus , V. parahaemolyticus , and E. tarda in Japanese flounder, the cell-cultured inactivated vaccine against grass carp hemorrhagic disease, the inactivated vaccine against fish infectious spleen and kidney necrosis virus (ISKNV), and the genetically engineered live vaccine against V. anguillarum in turbot. Moreover, different delivery routes of fish vaccines are also compared in this review, along with differential fish immune response after vaccination. All these efforts will ultimately benefit the healthy and sustainable development of aquaculture industry in China. • Summarized seven certified vaccine products in China. • Demonstrated the future development of fish vaccines in China. • Compared fish immune responses after different vaccination strategies. [ABSTRACT FROM AUTHOR]

Infected yellow catfish ( Pelteobagrus fulvidraco) were sent from Niushan Lake Fishery, Hubei Province, China, to our laboratory for diagnosis. Macroscopic daffodil yellow mold was observed on the heads and fins of the fish and one Mucor species was isolated. Based on the morphological and molecular analysis, the species was identified as Mucor circinelloides. Its optimum growth temperature was 30 °C and it could not grow at 40 °C. The infectivity results showed wound infection could cause 100% cumulative mortalities at all experimental CFU (106, 107 and 108). The cumulative mortalities of the intraperitoneal infection increased along with the sporangiospore concentrations; the highest mortality was 90% with 108 CFU. Histopathological studies showed M. circinelloides could cause a series of pathological changes in the host tissues and they disseminated in different viscera, perhaps by the blood. This is the first report of M. circinelloides infection in yellow catfish. [ABSTRACT FROM AUTHOR]

Abstract: Two Saprolegnia isolates, JY isolated from silver crucian carp (Carassius auratus gibelio Bloch) and BMY isolated from zebra fish (Brachydanio rerio Hamilton) came from infections occurring concurrently in different locations in China. To confirm whether the two isolates were from the same Saprolegnia clone, comparative studies have been carried out based on their morphological, physiological and molecular characteristics. Observations showed that morphologically (both asexual and sexual organs) the two isolates were broadly similar and both isolates underwent repeated zoospore emergence. Comparing 704 base pairs of internal transcribed spacer (ITS) region and the 5.8S rDNA, we found isolates JY and BMY shared an identical ITS sequence with a minor variation (99.6% similarity). Forty available sequences for representatives Saprolegnia spp. belonged to four phylogenetically separate clades. The two studied isolates fell within clade I that comprised a group of isolates which showed almost an identical ITS sequence but had been identified as a number of different morphological species. Our findings suggest that isolates JY and BMY appear to belong to the S. ferax clade and this clade (I) contains a number of closely related phylogenetic species. This is distinct from the more common fish pathogenic isolates, which belong to the S. parasitica clade (III) and are characterized by having cysts decorated by bundles of long hooked hairs and two further clades (II and IV) containing largely saprotrophic or soil born species. [Copyright &y& Elsevier]

This paper presents a research attempt to develop and evaluate a Web-based tele-diagnosis system for fish diseases. Fish disease diagnosis is a complicated process and requires high level of expertise. A tele-diagnosis system T-VET is being developed and tested in China. T-VET is the key sub system of a Web-based expert system for fish disease diagnosis. This paper looks at why a tele-diagnosis system is needed and what are the advantages and difficulties in developing and using such a system. The system''s architecture and components are described. A user-centered approach was adopted throughout the development process to ensure the system would meet users'' needs and will be accepted. As a result, the system functions were emerged and improved by users'' requirements. The experience and feedback from testing and evaluating the system with potential users are discussed. Some valuable insights into the use of the Internet as a tele-diagnosis tool in aquaculture are highlighted. [Copyright &y& Elsevier]

The outbreaks of fungal diseases in cultured fish have been severe in recent years, which is harmful to the healthy and sustainable development of fish farming. In this study, an investigation was conducted for significant fungal infections of 12 species of fish in four regions in Xinjiang, China, to understand the distribution of local fish fungal pathogens. Twenty-six fungal strains with pathogenicity were isolated, and the challenge experiment showed that eight strains from Changji area had high infection rate to fish eggs. Based on internal transcribed spacer sequence data and molecular analysis, the 26 strains were classified into nine different species of six fungal genera. Phylogenetic analysis showed that all strains were divided into two clades, namely Cluster 1 (contains only the genus Mucor) and Cluster 2 (consists of five small branches), and the distribution of strains from the same region was scattered in two clusters. There is no strict host selectivity for these fungi to infect fish. Mucor sp. are the main fungal pathogen of fish in these four regions, whereas Hypophthalmichthys molitrix and Carassius auratus are two types of fish that were susceptible to pathogen. In addition, the environmental adaptability experiments showed that eight highly pathogenic strains have different adaptability to the environment, and their optimum temperature and pH were 25°C and 7.0, respectively, whereas the concentration of NaCl was negatively correlated with the growth of strains. Therefore, these results indicated that the coinfection of multiple fungal pathogens in a culture region should be considered in the future study., (© 2021 Fisheries Society of the British Isles.)