Epidemiology of turbot bacterial diseases in China between October 2016 and December 2019

Abstract

Turbot (Scophthalmus maximus) is an important commercial fish in China that can be infected by a series of bacterial pathogens, leading to great economic losses. In this study we focused on the epidemiology of turbot bacterial diseases in the major farming areas in China for three years. A total of 155 cases with 446 diseased turbots were investigated, and dominant bacterial pathogens were isolated from 137 cases (344 turbots). Thus, bacteria are the major threat to farming turbot in China. Edwardsiella piscicida was the major pathogen, which isolated as the dominant colony in 62 cases (40.00%) with 151 turbots (33.85%). Aeromonas salmonicida was isolated in 57 cases (36.77%) with 116 turbots (26.01%). Vibrio anguillarum was isolated in nine cases (5.81%), and Streptococcus parauberis in five cases (3.23%). Photobacterium damselae and Mycobacterium marinum were also isolated from one or two diseased fish. Other Vibrio spp. were isolated in 15 cases (9.68%). Two species of pathogen were isolated in 13 cases, and three species (E. piscicida, A. salmonicida, and S. parauberis) in one case. In 19 cases, no bacteria were isolated. Based on the annual disease analysis, we found that the E. piscicida infection proportion of total cases was greatly decreased, which may be caused by the attenuated vaccine inoculated in 2018. The antibiotic resistance of E. piscicida strains isolated in Weifang city was also determined. We found that the resistance to ceftriaxone, doxycycline, and SMZ/TMP were significantly increased from October 2016 to June 2018, and all the E. piscicida isolates exhibited resistance to SMZ/TMP in June 2018. These results indicated that E. piscicida is the major threat to turbot farming in China, and the attenuated E. piscicida vaccine exhibits effective protection. The usage of antibiotics may induce resistance quickly. Thus, development of vaccines is an important work for sustainable development of turbot farming in the future.

Identification and genomic analysis of a pathogenic circovirus associated with maricultured Scophthalmus maximus L. in China

“…However, when the water temperature was below 13 °C or above 18 °C, fish mortality seldom occurred. The temperature pattern of the disease is similar to other reported occurrences ( Gao et al, 2023 ; Ke et al, 2011 ; Shi et al, 2004 ). Species such as Japanese Flounder ( Paralichthys olivaceus ) ( Gong et al, 2022 ), spotted knifejaw ( Oplegnathus punctatus ) ( Huang et al, 2021 ), and Chinese tongue sole ( Cynoglossus semilaevis ) ( Zhou et al, 2022 ), co-cultured with S. maximus in the same pond, were unaffected by the disease.…”

“…The turbot, a species of significant economic importance within the global aquaculture industry, has experienced rapid growth in recent years. The intensification of farming practices, coupled with the regular translocation of turbot, has led to an increased incidence of emerging diseases within this species ( Gao et al, 2023 ; Ke et al, 2011 ; Shi et al, 2004 ; Sun et al, 2022 ). An emerging disease among farmed turbot populations has recently gained momentum in China, presenting a highly contagious and potentially devastating threat to the sustainability and expansion of the aquaculture industry.…”

“…Scophthalmus maximus L., commonly known as turbot, has long been a staple in European aquaculture and was introduced to China in 1992. It has since become a significant species in the mariculture industry, particularly along the northern coastal regions of China ( Gao et al, 2023 ). As reported by the China Fishery Statistical Yearbook , the production of flatfish with turbot being the primary contributor, reached 100.694 thousand tons in 2022.…”

Multiomics uncovers the epigenomic and transcriptomic response to viral and bacterial stimulation in turbot

“…Turbot ( Scophthalmus maximus ) is a valuable farmed fish in Europe and Asia (more than 100,000 tons), with the highest production in China (Gao et al, 2023) followed by Spain (APROMAR 2022). Turbot is in its 6 th generation of selective breeding and infectious disease outbreaks constitute one of the main challenges this young industry faces (Martínez et al, 2021; Gao et al, 2023). This is a broader trend shared by global aquaculture, where infectious diseases cause losses of totalling more than 5,000 M€ per year (Mishra et al, 2018).…”

“…Turbot (Scophthalmus maximus) is a valuable farmed fish in Europe and Asia (more than 100,000 tons), with the highest production in China (Gao et al, 2023) followed by Spain (APROMAR 2022). Turbot is in its 6 th generation of selective breeding and infectious disease outbreaks constitute one of the main challenges this young industry faces Gao et al, 2023).…”