Whole genome sequence and characterisation of Streptococcus suis 3112, isolated from snakeskin gourami, Trichopodus pectoralis.

Background: Streptococcus suis (S. suis) is an important swine and human pathogen. A recent study reported the first isolate of S.

Structural modelling and preventive strategy targeting of WSSV hub proteins to combat viral infection in shrimp Penaeus monodon.

White spot syndrome virus (WSSV) presents a considerable peril to the aquaculture sector, leading to notable financial consequences on a global scale. Previous studies have identified hub proteins, including WSSV051 and WSSV517, as essential binding elements in the protein interaction network of WSSV. This work further investigates the functional structures and potential applications of WSSV hub complexes in managing WSSV infection.

Genome Characterization and Phylogenetic Analysis of Scale Drop Disease Virus Isolated from Asian Seabass ().

Scale drop disease virus (SDDV), a double-stranded DNA virus in the family , has been reported widely in southeast Asian countries as a causative agent of scale drop syndrome (SDS) in Asian seabass. SDS has resulted in high mortality and significant economic losses to the aquaculture industry. This study demonstrated the use of metagenomic methods to investigate bacterial and viral communities present in infected fish tissues and recover a complete genome of the causative agent named SDDV TH7_2019.

Protective efficiency and immune responses to single and booster doses of formalin-inactivated scale drop disease virus (SDDV) vaccine in Asian seabass (Lates calcarifer).

Background: Scale drop disease virus (SDDV) threatens Asian seabass (Lates calcarifer) aquaculture production by causing scale drop disease (SDD) in Asian seabass. Research on the development of SDDV vaccines is missing an in-depth examination of long-term immunity and the immune reactions it provokes. This study investigated the long-term immune protection and responses elicited by an SDDV vaccine.

WSSV early protein WSSV004 enhances viral replication by suppressing LDH activity.

White spot syndrome virus (WSSV) is known to upregulate glycolysis to supply biomolecules and energy for the virus's replication. At the viral genome replication stage, lactate dehydrogenase (LDH), a glycolytic enzyme, shows increased activity without any increase in expression. In the present study, yeast 2-hybrid screening was used to identify WSSV proteins that interacted with LvLDH isoform 1 and 2, and these included the WSSV early protein WSSV004.

A novel vaccination strategy against Vibrio harveyi infection in Asian seabass (Lates calcarifer) with the aid of oxygen nanobubbles and chitosan.

Immersion vaccination, albeit easier to administer than immunization by injection, sometimes has challenges with antigen uptake, resulting in sub-optimal protection. In this research, a new strategy to enhance antigen uptake of a heat-inactivated Vibrio harveyi vaccine in Asian seabass (Lates calcarifer) using oxygen nanobubble-enriched water (ONB) and positively charged chitosan (CS) was explored. Antigen uptake in fish gills was assessed, as was the antibody response and vaccine efficacy of four different combinations of vaccine with ONB and CS, and two control groups.

End-point rapid detection of total and pathogenic ( and/or and/or ) in raw seafood using a colorimetric loop-mediated isothermal amplification-xylenol orange technique.

Background: is the leading cause of bacterial seafood-borne gastroenteritis in humans worldwide. To ensure seafood safety and to minimize the occurrence of seafood-borne diseases, early detection of total (pathogenic and non-pathogenic strains) and pathogenic ( and/or and/or ) is required. This study further improved a loop-mediated isothermal amplification (LAMP) assay using xylenol orange (XO), a pH sensitive dye, to transform conventional LAMP into a one-step colorimetric assay giving visible results to the naked eye.

First Investigation of the Optimal Timing of Vaccination of Nile Tilapia () Larvae against .

To investigate early immune responses and explore the optimal vaccination periods, Nile tilapia at 1, 7, 14, 21, 28, 35, and 42 days after yolk sac collapse (DAYC) were immersed in formalin-killed vaccine (FKV-SA). A specific IgM was first detected via ELISA in the 21 DAYC larvae (0.108 g) at 336 h after vaccination (hav), whereas in the 28-42 DAYC larvae (0.

Evaluate the potential use of TonB-dependent receptor protein as a subunit vaccine against Aeromonas veronii infection in Nile tilapia (Oreochromis niloticus).

Aeromonas veronii is an emerging bacterial pathogen that causes serious systemic infections in cultured Nile tilapia (Oreochromis niloticus), leading to massive deaths. Therefore, there is an urgent need to identify effective vaccine candidates to control the spread of this emerging disease. TonB-dependent receptor (Tdr) of A.

Immersion prime and oral boost vaccination with an inactivated Vibrio harveyi vaccine confers a specific immune response and protection in Asian seabass (Lates calcarifer).

Asian seabass (Lates calcarifer) holds significant economic value in fish farming in the Asia-Pacific region. Vibriosis caused by Vibrio harveyi (Vh) is a severe infectious disease affecting intensive farming of this species, for which prevention strategies by vaccination have been developed. This study investigated an alternative approach to injectable vaccination to prevent vibriosis in Asian seabass juveniles.

A multiplexed RT-PCR assay for nanopore whole genome sequencing of Tilapia lake virus (TiLV).

Tilapia lake virus (TiLV) is a highly contagious viral pathogen that affects tilapia, a globally significant and affordable source of fish protein. To prevent the introduction and spread of TiLV and its impact, there is an urgent need for increased surveillance, improved biosecurity measures, and continuous development of effective diagnostic and rapid sequencing methods. In this study, we have developed a multiplexed RT-PCR assay that can amplify all ten complete genomic segments of TiLV from various sources of isolation.

Effects of hyperoxia during oxygen nanobubble treatment on innate immunity, growth performance, gill histology, and gut microbiome in Nile tilapia, Oreochromis niloticus.

Oxygen nanobubble (NB-O) technology has been introduced to the aquaculture industry in recent years. This treatment usually results in a tremendously high level of dissolved oxygen (DO) in the water. However, little is known about the possible negative effects of hyperoxia due to NB-O treatment (hyper-NB-O) on farmed fish.

Improving the diagnosis of Streptococcus iniae using a novel probe-based qPCR assay combined with an enrichment step.

Streptococcus iniae is a bacterial pathogen that causes streptococcosis, leading to significant losses in fish aquaculture globally. This study reported a newly developed probe-based quantitative polymerase chain reaction (qPCR) method for the detection of S. iniae.

Synthetic peptides derived from predicted B cell epitopes of nervous necrosis virus (NNV) show antigenicity and elicit immunogenic responses in Asian seabass (Lates calcarifer).

Nervous necrosis virus (NNV) has spread throughout the world, affecting more than 120 freshwater and marine fish species. While vaccination effectively prevents disease outbreaks, the difficulty of producing sufficient viruses using cell lines continues to be a significant disadvantage for producing inactivated vaccines. This study, therefore, explored the application of synthetic peptides as potential vaccine candidates for the prevention of NNV in Asian seabass (Lates calcarifer).

Immunological response of 35 and 42 days old Asian seabass (Lates calcarifer, Bloch 1790) fry following immersion immunization with Streptococcus iniae heat-killed vaccine.

Early disease prevention by vaccination requires understanding when fry fish develop specific immunity to a given pathogen. In this research, we explored the immune responses of Asian seabass (Lates calcarifer) at the stages of 35- and 42- days post-hatching (dph) to an immersive heat-killed Streptococcus iniae (Si) vaccine to determine whether fish can produce specific antibodies against the pathogen. The vaccinated fish of each stage (V35 and V42) were immersed with the Si vaccine at 10 CFU/ml for 3 h, whereas the control groups (C35 and C42) were immersed with tryptic soy broth (TSB) in the same manner.

Immune Activation Following Vaccination of Bacterin in Asian Seabass (, Bloch 1790).

Juvenile Asian seabass () (body weight 10 ± 0.7 g) were intraperitoneally injected with 10 CFU fish of formalin-killed . The protective efficacy of the vaccine on survival and infection rate was assessed upon challenge at 4, 8, 12, 20, and 28 weeks post-vaccination.

Usefulness of the pancreas as a prime target for histopathological diagnosis of Tilapia parvovirus (TiPV) infection in Nile tilapia, Oreochromis niloticus.

Tilapia parvovirus (TiPV) is an emerging virus reportedly associated with disease and mortality in farmed tilapia. Although previous descriptions of histopathological changes are available, the lesions reported in these are not pathognomonic. Here, we report Cowdry type A inclusion bodies (CAIB) in the pancreas as a diagnostic histopathological feature found in adult Nile tilapia naturally infected with TiPV.

Concentration and quantification of from water using a simple iron flocculation coupled with probe-based RT-qPCR.

Background: , also known as tilapia lake virus (TiLV), is a significant virus that is responsible for the die-off of farmed tilapia across the globe. The detection and quantification of the virus using environmental RNA (eRNA) from pond water samples represents a potentially non-invasive and routine strategy for monitoring pathogens and early disease forecasting in aquaculture systems.

Methods: Here, we report a simple iron flocculation method for concentrating viruses in water, together with a newly-developed hydrolysis probe quantitative RT-qPCR method for the detection and quantification of TiLV.

Pre-treatment of Nile tilapia (Oreochromis niloticus) with ozone nanobubbles improve efficacy of heat-killed Streptococcus agalactiae immersion vaccine.

Nanobubble technology has shown appealing technical benefits and potential applications in aquaculture. We recently found that treatment with ozone nanobubbles (NB-O) activated expression of several immune-related genes leading to effective response to subsequent exposure to fish pathogens. In this study, we investigated whether pre-treatment of Nile tilapia (Oreochromis niloticus) with NB-O can enhance specific immune responses and improve efficacy of immersion vaccination against Streptococcus agalactiae.

Immunization of Nile Tilapia () Broodstock with Tilapia Lake Virus (TiLV) Inactivated Vaccines Elicits Protective Antibody and Passive Maternal Antibody Transfer.

Tilapia lake virus (TiLV), a major pathogen of farmed tilapia, is known to be vertically transmitted. Here, we hypothesize that Nile tilapia () broodstock immunized with a TiLV inactivated vaccine can mount a protective antibody response and passively transfer maternal antibodies to their fertilized eggs and larvae. To test this hypothesis, three groups of tilapia broodstock, each containing four males and eight females, were immunized with either a heat-killed TiLV vaccine (HKV), a formalin-killed TiLV vaccine (FKV) (both administered at 3.

Detection and characterization of Kudoa thunni from uncooked yellowfin tuna (Thunnus albacares) in Southeast Asia.

Myxosporean parasites Kudoa spp. have been reported in several marine fish species worldwide. However, little is known about the contamination of these parasites in raw fish in Southeast Asia, where the consumption demand of uncooked fish is increasing.