Global aquaculture production yielded a record of 122.9 million tons in 2022. However, ~10% of farmed aquatic animal production is lost each year due to various infectious diseases, resulting in substantial economic waste. Therefore, the development of vaccines is important for the prevention and control of aquatic infectious diseases. Gene-deletion live attenuated vaccines are efficacious because they mimic natural pathogen infection and generate a strong antibody response, thus showing good potential for administration via immersion. However, most gene-deletion viruses still have residual virulence, and thus, gene-deletion immersion vaccines for aquatic viruses are rarely developed. In this study, an orf074r deletion strain (Δorf074r) of ISKNV with residual virulence was constructed, and an immunization process was developed to reduce its residual virulence at 22°C, thereby making it a potential immersion vaccine against ISKNV. Our work will aid in the development of an aquatic gene-deletion live-attenuated immersion vaccine.
It is known that filtering process always yields blurring and loss of details in image processing, especially in the case of noisy. In this paper, a new weighted adaptive guided filter (WAGIF) is proposed to estimate illumination component. Specifically, the proposed WAGIF consists of three steps: 1) Local skewness is employed to distinguish the flat areas and texture areas of the underlying image. 2) An adaptive regularization parameter is designed to filter the image adaptively according to the skewness. 3) The filtered results are weighted and aggregated to output the final image. After obtaining the illumination component, the Retinex model is used to obtain the reflection component. Furthermore, the illumination component is processed by sigmoid function and the reflection component is enhanced by gamma correction. Finally, the illumination component and the reflection component are reconstructed to obtain an image with high contrast and rich details. The experimental results show that the proposed method is better than the existing methods in terms of denoising performance and structure preservation for low-light image enhancement.
Infectious diseases seriously threaten sustainable aquaculture development, resulting in more than $10 billion in economic losses annually. Immersion vaccines are emerging as the key technology for aquatic disease prevention and control. Here, a safe and efficacious candidate immersion vaccine strain (Δorf103r/tk) of infectious spleen and kidney necrosis virus (ISKNV), in which the orf103r and tk genes were knocked out by homologous recombination, is described. Δorf103r/tk was severely attenuated in mandarin fish (Siniperca chuatsi), inducing mild histological lesions, a mortality rate of only 3%, and eliminated within 21 days. A single Δorf103r/tk immersion-administered dose provided long-lasting protection rates over 95% against lethal ISKNV challenge. Δorf103r/tk also robustly stimulated the innate and adaptive immune responses. For example, interferon expression was significantly upregulated, and the production of specific neutralizing antibodies against ISKNV was markedly induced postimmunization. This work provides proof-of-principle evidence for orf103r- and tk-deficient ISKNV for immersion vaccine development to prevent ISKNV disease in aquaculture production. IMPORTANCE Global aquaculture production reached a record of 122.6 million tons in 2020, with a total value of 281.5 billion U.S. dollars (USD). However, approximately 10% of farmed aquatic animal production is lost due to various infectious diseases, resulting in more than 10 billion USD of economic waste every year. Therefore, the development of vaccines to prevent and control aquatic infectious diseases is of great significance. Infectious spleen and kidney necrosis virus (ISKNV) infection occurs in more than 50 species of freshwater and marine fish and has caused great economic losses to the mandarin fish farming industry in China during the past few decades. Thus, it is listed as a certifiable disease by the World Organization for Animal Health (OIE). Herein, a safe and efficient double-gene-deleted live attenuated immersion vaccine against ISKNV was developed, providing an example for the development of aquatic gene-deleted live attenuated immersion vaccine.
Aquaculture provides important food, nutrition, and income sources for humans. However, aquaculture industry is seriously threatened by viral diseases. Infectious spleen and kidney necrosis virus (ISKNV) disease causes high mortality and economic losses to the fish culture industry in Asia and has been listed as a certifiable disease by the International Epizootic Office. Vaccine development is urgent to control this disease. Here, a gene-deleted live attenuated candidate vaccine (ΔORF022L) against ISKNV with low pathogenicity and high protection was developed. ΔORF022L replicated well in mandarin fish fry-1 cells and showed similar structure with wild-type ISKNV. However, the pathogenicity was significantly lower as 98% of the mandarin fish infected with ΔORF022L survived, whereas all those infected with wild-type ISKNV died. Of importance, 100% of the ΔORF022L-infected fish survived the ISKNV challenge. ΔORF022L induced anti-ISKNV specific antibody response and upregulation of immune-related genes. This work could be beneficial to the control of fish diseases.
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