Zoonotic diseases of fish and their prevention and control

Function of three newly identified galectins in immune response of Takifugu obscurus against bacterial infection

Galectins, a family of β-galactoside-binding proteins, are evolutionarily conserved across diverse organisms. In our research, three galectins were identified from Takifugu obscurus, designated as ToGalec9, ToGalec10, and ToGalec11. Structural analysis revealed that the deduced proteins contain one, one, and two conserved carbohydrate recognition domains, respectively. Transcripts of ToGalec9-11 exhibited ubiquitous expression across all examined tissues, with significant upregulation observed in liver and kidney tissues following challenge with Vibrio harveyi and Staphylococcus aureus. siRNA-mediated knockdown of ToGalec9-11 downregulated four interleukin (IL) genes expression and substantially impaired bacterial clearance capacity. To further elucidate biological functions, the coding regions of ToGalec9-11 were expressed and the proteins were purified. The recombinant ToGalec9-11 proteins demonstrated broad carbohydrate-binding specificity against six tested ligands and displayed potent bacterial agglutination activity against both Gram-negative (V. harveyi) and Gram-positive (S. aureus) pathogens. Furthermore, rToGalec9-11 exhibited significant antimicrobial effects by suppressing bacterial proliferation and biofilm formation. Notably, rToGalec9-11 enhanced the expression of four IL genes and facilitated bacterial clearance in vivo. Our findings collectively demonstrate that ToGalec9-11 function as essential immune mediators in T. obscurus, orchestrating pathogen recognition, antimicrobial defense, and immune modulation through both lectin-mediated interactions and cytokine regulation.

Zoonotic Agents in Farmed Fish: A Systematic Review from the Interdisciplinary Perspective of the One Health Concept

This systematic review aims to synthesize evidence on zoonotic agents in farmed fish from the interdisciplinary One Health perspective. The review followed a protocol, following the PICOS strategy, where P represents population (farmed fish), I represents intervention (fish diseases), C represents comparison (healthy fish), O represents outcome (One Health) and S represents the type of study (experimental studies). The searches were conducted in the SCOPUS, Science Direct and PubMed Central databases. Of the 400 articles identified, 23 met the inclusion criteria due to their methodological robustness. These articles focused predominantly on parasitic (60.9%) and bacterial (39.1%) zoonotic agents. The One Health approaches discussed throughout the articles included host-parasite interactions (35%), antimicrobial resistance (22%), infections and food safety (18%), nutrition and immune responses (17%), stress and immune responses (4%) and anthelmintic testing (4%). The findings indicate that high-level scientific production is often confined to specific fields, such as veterinary medicine, biological sciences and animal science/fishery resources. There is a lack of broad interdisciplinary collaboration, limiting the integration of diverse fields to improve scientific production.

Biofilm formation and analysis of EPS architecture comprising polysaccharides and lipids by Pseudomonas aeruginosa and Escherichia coli on food processing surfaces

Biofilms are silent but formidable threats in seafood processing, where Pseudomonas aeruginosa and Escherichia coli can quickly transform contact surfaces into reservoirs of contamination. This study explores the dynamic biofilm formation on aluminum, silicone rubber, stainless steel, and polyethylene terephthalate over 24 and 72 h. Quantitative assays including Colony Forming Unit (CFU), Crystal Violet (CV), 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) revealed a significant increase in biofilm density, particularly on aluminum and silicone rubber. Fourier-Transform Infrared Spectroscopy (FTIR) and 1H Nuclear Magnetic Resonance (NMR) analyses showed that biofilm EPS exhibits an evolving amphiphilic nature, with stable polysaccharides and increasing lipid content enhancing resilience. Confocal Laser Scanning Microscopy (CLSM), and Field Emission Scanning Electron Microscopy (FE-SEM) captured the shift from early attachment to mature, dense biofilms. These findings underscore the crucial impact of surface material on biofilm growth and the pressing need for tailored cleaning protocols to curb contamination risks in food processing environments.

Phage-derived proteins: Advancing food safety through biocontrol and detection of foodborne pathogens

The emergence of antimicrobial-resistant foodborne pathogens poses a continuous health risk and economic burden as they can easily spread through contaminated food. Therefore, the demand for new antimicrobial agents to address this problem is steadily increasing. Similarly, the development of rapid, sensitive, and accurate pathogen detection tools is a prerequisite for ensuring food safety. Phage-derived proteins have become innovative tools for combating these pathogens because of their potent antimicrobial activity and host specificity. Phage proteins are relatively free from regulation compared to phages per se, and there are no concerns about the transduction of harmful genes. With recent progress in next-generation sequencing technology, the analysis of phage genomes has become more accessible, and numerous phage proteins with potential for biocontrol and detection have been identified. This review provides a comprehensive overview of phage protein research on food safety from 2006 to the present, a pivotal period marked by the certification of phages as Generally Recognized As Safe (GRAS). Emphasizing recent advancements, we investigated the diverse applications of various phage proteins for biocontrol and detection purposes. While highlighting the successful implementation of these proteins, we also address the current bottlenecks and propose strategies to overcome these challenges. By summarizing the current state of research on phage-derived proteins, this review contributes to a deeper understanding of their potential as effective antimicrobial agents and tools for detecting foodborne pathogens.

Advanced genomic research in understanding fish-borne zoonotic parasitic infection

Fish-borne zoonotic parasites pose substantial risks to human health and global aquaculture, primarily through raw or undercooked fish consumption. The rapid expansion of aquaculture, increasing global fish trade, and rising human populations have amplified these concerns. Despite widespread awareness of meat-borne zoonoses, fish-borne parasitic infections remain underrecognized, especially in developed countries. Traditional morphological and molecular methods have provided critical foundations for studying these parasites, yet recent genomic advances have revolutionized our understanding of their genetic diversity, biology, and host-pathogen dynamics. This review underscores the significance of integrating genomic approaches with conventional methods to enhance disease surveillance, risk assessment, and control strategies. Harnessing genomic tools will enable the development of effective interventions to mitigate zoonotic parasite impacts, protect human health, and promote sustainable aquaculture. A comprehensive, genomics-driven approach is essential to overcoming the global challenges of fish-borne zoonotic infections.

Aeromonas characteristics in Iran, Southwest Asia; a systematic review and meta-analysis on epidemiology, reservoirs and antibiotic resistance profile from aquatic environments to human society during 2000-2023

BACKGROUND

As recent evidence shows the prevalence and transmission of Aeromonas species in Southwest Asia, and there is no updated information on the characteristics of Aeromonas in Iran, we conducted this review. We systematically searched biomedical databases (PubMed, Web of Sciences, Scopus, SID, ISC, and Google Scholar) to identify relevant studies investigating the prevalence, antibiotic resistance, and main reservoirs of Aeromonas in aquatic animals and human clinical specimens during 2000-2023 in Iran. Cochrane's Q test and I^2 statistical test was used to assess heterogeneity, and publication bias was assessed using funnel plots and random effects tests.

RESULTS

In Iran, among 8347 human clinical samples and 1802 animal and food samples, only 87 (1.04%) and 388 (21.53%) samples were positive for Aeromonas spp. respectively, and the most isolated species was A. hydrophila. The main reservoir for Aeromonas spp. were twenty-four genera of aquatic animals besides minced meat, pigeon stool and chicken meat. In Iran, Aeromonas spp. isolates showed maximum resistance to ampicillin, tetracycline, nalidixic acid and vancomycin. The heterogeneity test for prevalence of Aeromonas species on human samples and animals or food products was significant (88.1256, (5), P-value < 0.0001) and the heterogeneity rate was 97.34% with a confidence interval of 0.2-4.3 and (194.02, (10), P-value < 0.0001) and the heterogeneity rate was 94.85% with a confidence interval of 15,124 - 33,335 respectively.

CONCLUSIONS

According to these results, it is essential for exclusive attention to the prevalence and antibiotic resistance of Aeromonas in different provinces of Iran. Furthermore, special planning should be done for prevention, outbreak control and proper treatment of infections in the aquaculture industry and human societies.

Microbiological Hazards in the Food Chain of Fish and Products, a Focus on Klebsiella spp

Feeding is an elementary human need from which we obtain the energy and nutrients necessary for development and survival. Health heavily depends on food, which can be a means of different microbial hazards when contaminated at any stage of the food chain, compromising food safety and consumer health. Fish are considered widely produced foods (fishing or aquaculture) and are marketed worldwide; they are also a basic element of the human diet because they are a source of proteins and lipids. On the other hand, owing to their chemical properties (neutral pH and water activity), fish are highly susceptible to contamination by saprophytic and pathogenic microorganisms related to spoilage and risk to human health. Among the contaminating microorganisms in fish are bacteria of the genus Klebsiella, which are considered important in human and animal health worldwide due to their opportunistic pathogenicity, resistance to various antimicrobials, and association with numerous infections at the community and hospital levels, where foods such as fish and other products can serve as important sources of transmission. Therefore, this document presents a bibliographic review focused on describing, in a general way, the genus Klebsiella and its relationship with human health, aquatic animal health, and the safety of fish and products, as well as laboratory analysis procedures and identification of control and prevention measures of this biological hazard in fish and products to safeguard public health.

Coccidia (Apicomplexa: Eucoccidiorida) of Freshwater Fish

The phylum Apicomplexa includes endoparasites of fish worldwide, which cause parasitic infections that can adversely affect productivity in aquaculture. They are considered bioindicators of water pollution. Piscine apicomplexan parasites can be divided into two major groups: the intracellular blood parasites (Adeleorina) and the coccidians (Eimeriorina), which can infect the gastrointestinal tract and several organs. This work aims to compile, as completely as possible and for the first time, the available information concerning the species of coccidia (Apicomplexa: Conoidasida), which has been reported from freshwater fish. A comprehensive bibliographic search was performed using all available databases and fields, including Scopus, PubMed, and Google Scholar. In the freshwater fish found, there were 173 described species. This review demonstrates that freshwater fish's eimeriid coccidia are better studied than adeleid coccidia. Studies of coccidian freshwater fish fauna indicate a high infection with Eimeria and Goussia species. The wealthiest coccidia fauna were found in the Cypriniformes, Perciformes, Siluriformes and Cichliformes fishes.

Medicinal and aromatic plants assisted bioremediation of ammonical and bacterial contaminants in aquaponics water

An experiment was conducted under laboratory conditions to examine the effect of sixteen medicinal and aromatic plants (MAPs), namely Aloe barbadensis, Cymbopogen citratus, Bacopa monnieri, Senna sigueana, Plantado ovata, Asparagus racemosses, Phylanthus emblica, Vitex negundo, Cammiphora wightii, Cymbopogon martini, Andrographis paniculate, Ocimum tenuiflorum, Gymnema sylvestre, Centella asiatica, Adhatoda vasica, and Cyamopsis tetragonoloba in the removal of total ammonia-N (TAN) from aquaponics water. The different dried and grounded MAPs were added @ 100 mgl-1 into individual conical flasks containing 100 ml aquaponics water (spiked with 5 mgl-1 ammonia) and placed in a shaker. The effectiveness of different MAPs in removing TAN was evaluated at 24 hrs intervals until one of the MAPs achieved a removal rate of over 80%. The study also investigated their potential activity against fish bacterial pathogens viz. Edwardsiella tarda, Escherichia coli, Vibrio parahaemolyticus, Aeromonas hydrophila, and Staphylococcus aureus using the agar well diffusion method. The study indicates a negligible removal of TAN in the first twelve hours for all the MAPs. TAN concentration significantly reduced from 24 hrs for amla-treated water followed by satavari-treated water. Within 96 hrs., amla, satavari, and jalbrahmi removed 88.13 ± 0.81%, 79.52 ± 2.27%, and 77.22 ± 0.70 of TAN respectively. Other MAPs showed little effectiveness in removing ammonia, while cluster beans and ardushi increased the ammonia level in the water. Additionally, the methanol extract of amla exhibited strong antibacterial activities against all tested pathogens especially, against E. tarda. This study suggests the potential application of a MAP-based One-Health approach for mitigating abiotic and biotic stresses in aquaculture. PRACTITIONER POINTS: Evaluated 16 different medicinal and aromatic plants (MAPs) for their ammonia removal activity from aquaponics water. Amla treated water showed the highest ammonia removal followed by Satavaari and Jalbrahmi. Cluster beans and Ardushi treated water resulted in increasing ammonia levels due to their high nitrogen contents. Methanolic extract of amla showed bactericidal activity against fish pathogens Edwardsiella tarda, E. coli, Vibrio parahaemolyticus, A. hydrophila, and S. aureus. Potential applications in developing aquaponics production system of fish with medicinal plants through nutrient cycling and water recycling.

Silent Carriers: The Hidden Threat of Antibiotic-Resistant Staphylococcus aureus in Retail Seafood Across Poland's Tri-City Area

Background/objectives: Antibiotic-resistant Staphylococcus aureus poses a significant risk to food safety and public health, particularly through the consumption of contaminated seafood. This study aimed to assess the presence and antibiotic resistance of S. aureus in seafood sold in the Tri-City area of Poland, addressing a knowledge gap regarding the region. Methods: Seafood samples (n = 89) were categorized according to their origin: domestic-Poland (PL), European countries (ECs), and Asian countries (ACs). S. aureus was isolated using ISO 6888-1 methods, and antimicrobial susceptibility testing was conducted against three antibiotics: erythromycin, clindamycin, and gentamicin, following CLSI guidelines. Results: Of the 89 samples, 68.5% were contaminated with S. aureus. The highest resistance rates were found for erythromycin (30.5%), with gentamicin showing the lowest resistance (8.3%).No significant correlation (p > 0.05) was found between resistance patterns and fish origin or processing level. Conclusions: The results of this study highlight the widespread occurrence of Staphylococcus aureus in fish sold in the Tri-City area, with a notable prevalence of antibiotic-resistant strains.

Current disease treatments for the ornamental pet fish trade and their associated problems

The trade in live ornamental fishes to be held as companion animals or displayed in public aquaria has an estimated global annual value of US$15–20 billion. Supply chains for ornamental pet fishes often involve many more parties than for fish farmed as food fishes, and at each stage, fishes are exposed to stressors including handling, confinement, crowding, mechanical disturbance, and poor water quality. If chronic, these stressors can compromise their immune system, making fishes more susceptible to pathogens. Mortality and morbidity from infectious disease can result in considerable welfare impacts and massive economic losses for the industry, and the range of infective agents seen in ornamental species is well documented. However, treating these diseases is not straightforward with practices varying greatly across the trade and with several approaches having unintended consequences, such as the emergence of resistant strains of pathogens. While disease treatments for a handful of fish species (e.g., koi, goldfish) have received focused research attention, for the home aquarium owner, there is an increasing reliance on products based on natural compounds which have received far less scientific attention. This review aims to highlight the gaps in our knowledge surrounding the range of disease treatments used across the ornamental pet fish trade, with a particular focus on freshwater tropical species destined for home aquaria. Consideration is given to the potential problems arising from these treatments, including microbial resistance and effects of treatments themselves on fish health and welfare.

Copromicroscopic Diagnosis and Prevalence of Parasitic Infections in Animals in Sitio Ibayo, San Mateo, Rizal, Philippines: Establishing a Sentinel Study for Zoonotic Disease Surveillance

BACKGROUND

This study investigates the prevalence and intensity of parasitic infections in animal fecal samples collected from Sitio Ibayo, San Mateo, Rizal, Philippines, a suburban community considered a potential sentinel site for zoonotic disease surveillance.

METHODS

Using cross-sectional sampling, 132 animal fecal samples were collected in the area exhaustively. Samples were processed through direct smear with saline solution and Lugol's iodine and flotation technique using mini- and fill-FLOTAC. Microscopy was conducted, and the photomicrographs were analyzed to identify the parasite.

RESULTS

This study revealed an overall prevalence of parasitic infection of 50.67%. The prevalence was 100% in birds, cats, doves, and a rabbit, whereas dogs showed a high prevalence of 68.75%, followed by ducks at 66.67% and humans at 44.44%. Notably, the parasitic infection among ruminants was low, including zero in cows. Farm animals such as pigs and chickens have 53.8% and 42.9% prevalence, respectively. The co-infection was seen as 24 (18.18%) samples had two types of parasites, 12 (9.09%) had three types of parasites, three (2.27%) had four types of parasites, and one (0.76%) had five types of parasites. A total of 17 genera/species of parasites were found, including those belonging to the phylum Nematoda, phylum Platyhelminthes, and phylum Protozoa. Intensity analysis of infections demonstrated high intensity of Capillaria spp. infections among 50% of the sampled birds and Eimeria spp. among 20% of the sampled geese, with most parasitic infections in the other categories at low intensity.

CONCLUSION

This study highlights the burden of parasitic infections among various animal groups in Sitio Ibayo. The prevalence and co-infections in companion animals, farm animals, and humans were notable. The high prevalence of parasites in dogs, cats, and birds underscores their potential role in maintaining and dispersing parasitic infections within the ecosystem. The predominance of low-intensity infections suggests that while immediate health impacts may be minimal for some hosts, multi-parasite infections raise concerns for ecosystem health and zoonotic transmission. Targeted interventions using the One Health approach, including improved hygiene practices, deworming programs, and public awareness campaigns, are needed to mitigate the spread of parasitic diseases in this community.

Advances in Vibrio-related infection management: an integrated technology approach for aquaculture and human health

Vibrio species pose significant threats worldwide, causing mortalities in aquaculture and infections in humans. Global warming and the emergence of worldwide strains of Vibrio diseases are increasing day by day. Control of Vibrio species requires effective monitoring, diagnosis, and treatment strategies at the global scale. Despite current efforts based on chemical, biological, and mechanical means, Vibrio control management faces limitations due to complicated implementation processes. This review explores the intricacies and challenges of Vibrio-related diseases, including accurate and cost-effective diagnosis and effective control. The global burden due to emerging Vibrio species further complicates management strategies. We propose an innovative integrated technology model that harnesses cutting-edge technologies to address these obstacles. The proposed model incorporates advanced tools, such as biosensing technologies, the Internet of Things (IoT), remote sensing devices, cloud computing, and machine learning. This model offers invaluable insights and supports better decision-making by integrating real-time ecological data and biological phenotype signatures. A major advantage of our approach lies in leveraging cloud-based analytics programs, efficiently extracting meaningful information from vast and complex datasets. Collaborating with data and clinical professionals ensures logical and customized solutions tailored to each unique situation. Aquaculture biotechnology that prioritizes sustainability may have a large impact on human health and the seafood industry. Our review underscores the importance of adopting this model, revolutionizing the prognosis and management of Vibrio-related infections, even under complex circumstances. Furthermore, this model has promising implications for aquaculture and public health, addressing the United Nations Sustainable Development Goals and their development agenda.

Decellularization of fish tissues for tissue engineering and regenerative medicine applications

Decellularization is the process of obtaining acellular tissues with low immunogenic cellular components from animals or plants while maximizing the retention of the native extracellular matrix structure, mechanical integrity and bioactivity. The decellularized tissue obtained through the tissue decellularization technique retains the structure and bioactive components of its native tissue; it not only exhibits comparatively strong mechanical properties, low immunogenicity and good biocompatibility but also stimulates in situ neovascularization at the implantation site and regulates the polarization process of recruited macrophages, thereby promoting the regeneration of damaged tissue. Consequently, many commercial products have been developed as promising therapeutic strategies for the treatment of different tissue defects and lesions, such as wounds, dura, bone and cartilage defects, nerve injuries, myocardial infarction, urethral strictures, corneal blindness and other orthopedic applications. Recently, there has been a growing interest in the decellularization of fish tissues because of the abundance of sources, less religious constraints and risks of zoonosis transmission between mammals. In this review, we provide a complete overview of the state-of-the-art decellularization of fish tissues, including the organs and methods used to prepare acellular tissues. We enumerated common decellularized fish tissues from various fish organs, such as skin, scale, bladder, cartilage, heart and brain, and elaborated their different processing methods and tissue engineering applications. Furthermore, we presented the perspectives of (i) the future development direction of fish tissue decellularization technology, (ii) expanding the sources of decellularized tissue and (iii) innovating decellularized tissue bio-inks for 3D bioprinting to unleash the great potential of decellularized tissue in tissue engineering and regenerative medicine applications.

Investigation of Carriers of Salmonella and Other Hydrogen Sulphide-Positive Bacteria in the Digestive Content of Fish from the Atlantic Area of Macaronesia: A Comparative Study of Identification by API Gallery and MALDI-TOF MS

Salmonella spp. are known pathogens in fish, with their presence potentially resulting from the contamination of the aquatic environment or improper handling. Accurate bacterial identification is crucial across various fields, including medicine, microbiology, and the food industry, and thus a range of techniques are available for this purpose. In this study, Salmonella spp. and other hydrogen sulphide-positive bacteria were investigated in the digestive contents of fish destined for consumption from the Atlantic area of Macaronesia. Two identification techniques were compared: the traditional API method and the MALDI-TOF MS technique. For the identification of Salmonella spp. carriers, 59 samples were processed following ISO 6579-1:2017. A total of 47 strains of Gram-negative bacilli were obtained. No Salmonella spp. isolates were detected. The most frequent genus was Enterobacter (76.50%), followed by Shewanella (10.63%). The MALDI-TOF MS technique showed a high concordance with the API technique, with 72.34% concordance at the species level. Both techniques demonstrated a high degree of concordance in the identification of Enterobacter cloacae, with 87.23% genus-level concordance and 12.76% non-concordant identifications. This study highlights the limitations of the API technique and the speed and precision of MALDI-TOF MS. The identified bacteria could pose a health risk to humans.

Hyperspectral imaging and deep learning for parasite detection in white fish under industrial conditions

Parasites in fish muscle present a significant problem for the seafood industry in terms of both quality and health and safety, but the low contrast between parasites and fish tissue makes them exceedingly difficult to detect. The traditional method to identify nematodes requires removing fillets from the production line for manual inspection on candling tables. This technique is slow, labor intensive and typically only finds about half the parasites present. The seafood industry has struggled for decades to develop a method that can improve the detection rate while being performed in a rapid, non-invasive manner. In this study, a newly developed solution uses deep neural networks to simultaneously analyze the spatial and spectral information of hyperspectral imaging data. The resulting technology can be directly integrated into existing industrial processing lines to rapidly identify nematodes at detection rates (73%) better than conventional manual inspection (50%).

Genomic insights into fish pathogenic bacteria: A systems biology perspective for sustainable aquaculture

Fish diseases significantly challenge global aquaculture, causing substantial financial losses and impacting sustainability, trade, and socioeconomic conditions. Understanding microbial pathogenesis and virulence at the molecular level is crucial for disease prevention in commercial fish. This review provides genomic insights into fish pathogenic bacteria from a systems biology perspective, aiming to promote sustainable aquaculture. It covers the genomic characteristics of various fish pathogens and their industry impact. The review also explores the systems biology of zebrafish, fish bacterial pathogens, and probiotic bacteria, offering insights into fish production, potential vaccines, and therapeutic drugs. Genome-scale metabolic models aid in studying pathogenic bacteria, contributing to disease management and antimicrobial development. Researchers have also investigated probiotic strains to improve aquaculture health. Additionally, the review highlights bioinformatics resources for fish and fish pathogens, which are essential for researchers. Systems biology approaches enhance understanding of bacterial fish pathogens by revealing virulence factors and host interactions. Despite challenges from the adaptability and pathogenicity of bacterial infections, sustainable alternatives are necessary to meet seafood demand. This review underscores the potential of systems biology in understanding fish pathogen biology, improving production, and promoting sustainable aquaculture.

Awareness of fish-borne zoonoses and prevalence of Contracaecum in Oreochromis niloticus and Lates niloticus collected from Lake Chamo, Arba Minch, Ethiopia

AIM

Many fish species can harbour a wide range of pathogenic agents in their tissues. Of many pathogens, the parasitic nematode of genus Contracaecum, which resides in the tissues of fish species, can results in fish-borne infections in humans. This study was planned to assess consumers' awareness of fish-borne zoonoses in the fishing sites of Lake Chamo, Arba Minch, Ethiopia. The study was also aimed at demonstrating the zoonotic nematode, Contracaecum parasites in the Oreochromis niloticus and Lates niloticus fishes collected from Lake Chamo, Arba Minch, Ethiopia.

METHODS AND RESULTS

Assessment of awareness about fish-borne zoonoses was conducted in randomly selected participants (n = 162) using face-to-face interviews via a structured and semi-structured questionnaire. Besides, 70 fishes (O. niloticus = 35 and L. niloticus = 35) were examined for the presence of larva of Contracaecum and other anisakid genera through standard dissection, pepsin-hydrochloric acid digestion and microscopic observation. Consumers have inadequate awareness about fish-borne zoonoses based on the answers they provided to the questions. The majority of respondents (82%) consume raw fish in the area. Of these, a significantly higher proportion were male (p < 0.001), completed their elementary or high school (p = 0.004), Orthodox Christian (p = 0.044), fishermen (p < 0.001) and participants without previous information about fish-borne zoonoses (p < 0.001). Overall, of examined fishes (n = 70), n = 15 (21.4%, 95% CI, 12.8-33.2) were infected with Contracaecum larva. A significant (p = 0.028) higher infection prevalence was noted in L. niloticus (34.3%, 95% CI, 19.7-52.3) compared to O. niloticus (8.6%, 95% CI, 2.2-24.2). A unit gram addition in the total weight of fish would significantly raise the risk of Contracaecum infection by 1% (p < 0.001).

CONCLUSIONS

The presence of Contracaecum, a zoonotic nematode in the fishes, which are often preferred by consumers for raw dishes, designates a high risk of possible fish-borne infections in the area. Thus, providing education and training for fishermen, visitors of the area, and local people who visit the area for fish consumption, it is inevitably important to minimize the risk. Furthermore, health workers should suspect fish-borne infections, such as anisakidosis in patients who have a history of raw fish consumption in Arba Minch, Ethiopia.

Evaluation of Praziquantel effectiveness in treating Nile tilapia clinostomid infections and its relationships to fish health and water quality : By

This study aimed to conduct a multidisciplinary investigation integrating detailed morphology, molecular characterization, water parameters, histopathology alteration, and the trials of treatment of Clinostomum spp. In this study, 300 Nile tilapia (Oreochromis niloticus) were collected from the farmed and wild Nile River at Al Bahr Al Aazam, Giza Governorate to assess Clinostomid infection prevalence. Fish and water samples were collected from private fish farms, and water drains at Dakahlia, and Giza, Egypt. Analysis of the water revealed inadequate water quality, particularly in the fish farms. Snails and piscivorous birds were abundant at fish collection sites. The recovered Clinostomid MCs morphological characteristics and COI gene sequence analysis identified them as Clinostomum complanatum, C. phalacrocoracis, and Euclinostomum heterostomum. Clinostomid MCs disturbed the fish's hematological and biochemical blood parameters. Bath treatment of parasitized fish with praziquantel (2 mg/L for 24 h) revealed a significant reduction in the number of vital MCs vs. infected fish (non-treated). Praziquantel (PZQ) is an effective and safe therapy for controlling Clinostomid infections affecting farmed Nile tilapia. The current findings indicate a link between poor environmental conditions and Clinostomum infections in tilapia. The study highlights the impacts of Clinostomid MCs on fish health and recommends bath treatment with PZQ as an efficient control method for these dangerous parasites to protect human and fish health.

Factors Affecting Yeast Digestibility and Immunostimulation in Aquatic Animals

The aquafeed industry increasingly relies on using sustainable and appropriate protein sources to ensure the long-term sustainability and financial viability of intensive aquaculture. Yeast has emerged as a viable substitute protein source in the aquaculture sector due to its potential as a nutritional supplement. A substantial body of evidence exists to suggest that yeast has the potential to act as an effective immune-stimulating agent for a range of aquaculture fish species. Furthermore, the incorporation of yeast supplements and feed additives has the potential to bolster disease prevention, development, and production within the aquaculture sector. Except for methionine, lysine, arginine, and phenylalanine, which are typically the limiting essential amino acids in various fish species, the various yeast species exhibit amino acid profiles that are advantageous when compared to fishmeal. The present review considers the potential nutritional suitability of several yeast species for fish, with particular attention to the various applications of yeast in aquaculture nutrition. The findings of this study indicate that the inclusion of yeast in the diet resulted in the most favorable outcomes, with improvements observed in the overall health, growth performance, and nutritional condition of the fish. Digestibility, a key factor in sustainable feed development, is discussed in special detail. Additionally, this review addresses the utilization of yeast as an immunostimulating agent for fish and its digestion in fish. Furthermore, the research emphasizes the necessity of large-scale production of yeast as a substitute for fishmeal in aquaculture.

Isopods infesting Atlantic bonefish (Albula vulpes) host novel viruses, including reoviruses related to global pathogens, and opportunistically feed on humans

Isopods infest fish worldwide, but their role as disease vectors remains poorly understood. Here, we describe infestation of Atlantic bonefish (Albula vulpes) in Belize with isopods in two of three locations studied, with infestation rates of 15 and 44%. Isopods fed aggressively, and infested fish showed missing scales and scars. Gross morphologic and molecular phylogenetic analyses revealed the isopods to cluster within the family Aegidae and to be most closely related to members of the genus Rocinela, which are globally distributed micro-predators of fish. Metagenomic analysis of 10 isopods identified 11 viruses, including two novel reoviruses (Reovirales) in the families Sedoreoviridae and Spinareoviridae. The novel sedoreovirus clustered phylogenetically within an invertebrate-specific clade of viruses related to the genus Orbivirus, which contains arboviruses of global concern for mammal health. The novel spinareovirus clustered within the fish-infecting genus Aquareovirus, which contains viruses of global concern for fish health. Metagenomic analyses revealed no evidence of infection of bonefish with the novel aquareovirus, suggesting that viremia in bonefish is absent, low, or transient, or that isopods may have acquired the virus from other fish. During field collections, isopods aggressively bit humans, and blood meal analysis confirmed that isopods had fed on bonefish, other fish, and humans. Vector-borne transmission may be an underappreciated mechanism for aquareovirus transmission and for virus host switching between fish and other species, which has been inferred across viral families from studies of deep virus evolution.

The effects of kelp powder and fucoidan on the intestinal digestive capacity, immune response, and bacterial community structure composition of large yellow croakers (Larimichthys crocea)

Feed terrestrial components can induce intestinal stress in fish, affecting their overall health and growth. Recent studies suggest that seaweed products may improve fish intestinal health. In this experiment, three types of feed were prepared: a basic diet (C group), a diet with 0.2 % fucoidan (F group), and a diet with 3 % kelp powder (K group). These diets were fed to large yellow croaker (Larimichthys crocea) over an 8-week period. Each feed was randomly assigned to three seawater cages (4.0 m × 4.0 m × 5.0 m) containing 700 fish per cage. The study assessed changes in growth and intestinal health, including intestinal tissue morphology, digestive enzyme activities, expression of immune-related genes, and bacterial community structure. Results showed that incorporating seaweed products into the diet improved the growth and quality traits of large yellow croakers and significantly enhanced their intestinal digestive capacity (P < 0.05). Specifically, the 0.2 % fucoidan diet significantly increased the intestinal villus length and the activities of digestive enzymes such as trypsin, lipase, and α-amylase (P < 0.05). The 3 % kelp powder diet significantly enhanced the intestinal crypt depth and the activities of trypsin and lipase (P < 0.05). Both seaweed additives significantly enhanced intestinal health by mitigating inflammatory factors. Notably, the control group's biomarkers indicated a high presence of potential pathogenic bacteria, such as Streptococcus, Pseudomonas, Enterococcus, Herbaspirillum, Neisseria, Haemophilus, and Stenotrophomonas. After the addition of seaweed additives, these bacteria were no longer the indicator bacteria, while the abundance of beneficial bacteria like Ligilactobacillus and Lactobacillus increased. Significant reductions in the expression of inflammatory factors (e.g., il-6, tnf-α, ifn-γ in the fucoidan group and il-8 in the kelp powder group) further supported these findings. Our findings suggested that both seaweed additives helped balance intestinal microbial communities and reduce bacterial antigen load. Considering the effects, costs, manufacturing, and nutrition, adding 3 % kelp powder to the feed of large yellow croaker might be preferable. This study substantiated the beneficial effects of seaweed on the aquaculture of large yellow croaker, particularly in improving intestinal health. These findings advocated for its wider and more scientifically validated use in fish farming practices.

Current Challenges of Vaccination in Fish Health Management

Vaccination is an essential method of immunological preventive care required for the health management of all animals, including fish. More particularly, immunization is necessary for in-land aquaculture to manage diseases in fish broodstocks and healthy seed production. According to the latest statistics in 2020, 90.3 million tons of capture fishery production was achieved from the aquaculture sector. Out of the above, 78.8 million tons were from marine water aquaculture sectors, and 11.5 million tons were from inland water aquaculture sectors. About a 4% decline in fish production was achieved in 2020 in comparison to 2018 from inland aquaculture sectors. On the other hand, the digestive protein content, healthy fats, and nutritional values of fish products are comparatively more affordable than in other meat sources. In 2014, about 10% of aquatic cultured animals were lost (costing global annual losses > USD 10 billion) due to infectious diseases. Therefore, vaccination in fish, especially in broodstocks, is one of the essential approaches to stop such losses in the aquaculture sector. Fish vaccines consist of whole-killed pathogens, protein subunits, recombinant proteins, DNA, or live-attenuated vaccines. Challenges persist in the adaption of vaccination in the aquaculture sector, the route of administration, the use of effective adjuvants, and, most importantly, the lack of effective results. The use of autogenous vaccines; vaccination via intramuscular, intraperitoneal, or oral routes; and, most importantly, adding vaccines in feed using top dressing methods or as a constituent in fish feed are now emerging. These methods will lower the risk of using antibiotics in cultured water by reducing environmental contamination.

Conjugal plasmid transfer in the plant rhizosphere in the One Health context

Introduction

Horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) is one of the primary routes of antimicrobial resistance (AMR) dissemination. In the One Health context, tracking the spread of mobile genetic elements (MGEs) carrying ARGs in agri-food ecosystems is pivotal in understanding AMR diffusion and estimating potential risks for human health. So far, little attention has been devoted to plant niches; hence, this study aimed to evaluate the conjugal transfer of ARGs to the bacterial community associated with the plant rhizosphere, a hotspot for microbial abundance and activity in the soil. We simulated a source of AMR determinants that could enter the food chain via plants through irrigation.

Methods

Among the bacterial strains isolated from treated wastewater, the strain Klebsiella variicola EEF15 was selected as an ARG donor because of the relevance of Enterobacteriaceae in the AMR context and the One Health framework. The strain ability to recolonize lettuce, chosen as a model for vegetables that were consumed raw, was assessed by a rifampicin resistant mutant. K. variicola EEF15 was genetically manipulated to track the conjugal transfer of the broad host range plasmid pKJK5 containing a fluorescent marker gene to the natural rhizosphere microbiome obtained from lettuce plants. Transconjugants were sorted by fluorescent protein expression and identified through 16S rRNA gene amplicon sequencing.

Results and discussion

K. variicola EEF15 was able to colonize the lettuce rhizosphere and inhabit its leaf endosphere 7 days past bacterial administration. Fluorescence stereomicroscopy revealed plasmid transfer at a frequency of 10-3; cell sorting allowed the selection of the transconjugants. The conjugation rates and the strain's ability to colonize the plant rhizosphere and leaf endosphere make strain EEF15::lacIq-pLpp-mCherry-gmR with pKJK5::Plac::gfp an interesting candidate to study ARG spread in the agri-food ecosystem. Future studies taking advantage of additional environmental donor strains could provide a comprehensive snapshot of AMR spread in the One Health context.

Is it possible to eliminate or eradicate human fish-borne parasitic diseases? A sweet dream or a nightmare?

Human fish-borne parasitic diseases may be caused by at least 111 taxa of both freshwater and marine fish parasites. It is estimated that they occur in many hundreds of millions of people all over the world, and many more are at risk, sometimes with serious consequences including the death of the host. Therefore, all efforts must be made to minimize and prevent the infection. In this paper we present an overview detailing the several types of parasites infecting humans, the reasons for the occurrence of the disease, the ways of infection, the preventive measures and difficulties encountered when combating such infections. Finally, we discuss the possibility of eliminating or eradicating fish-borne diseases. It is concluded that elimination is difficult to achieve but it is possible in some places under favourable circumstances, and that eradication will probably never be fully achieved.

Risk Communication on Zoonoses and Antimicrobial Resistance-How Do Exotic Pet Owners Perceive the Communication of Their Veterinarians?

Exotic animals traded and kept as pets can transmit a variety of diseases to humans and other animals, and vice versa. Therefore, it is essential for pet owners, particularly vulnerable groups, to be informed about associated risks. Veterinarians play a crucial role in informing pet owners about health risks associated with zoonotic pathogens and antimicrobial resistance (AMR) and should, therefore, have good communication skills to effectively transfer information to pet owners. Thus, exotic pet owners in Germany were surveyed on animal husbandry, veterinary consultation and risk communication. To evaluate the perception of communication, a self-developed questionnaire was used to derive a communication score. The perception of veterinarian communication received a high average score showing a high level of satisfaction. The duration of the veterinarian-client relationship was associated with better communication perception, and the frequency of communication on zoonoses and AMR was associated with the presence of a permanent veterinarian. However, the results indicated that the frequency of disseminated information on zoonoses and/or AMR from veterinarians was lower than desired by the pet owners. Therefore, more educational material on zoonoses and AMR should be made available, and the awareness concerning risk communication should be increased by further education and training at universities.

Bridging aquatic invasive species threats across multiple sectors through One Biosecurity

Understanding the magnitude of biosecurity risks in aquatic environments is increasingly complex and urgent because increasing volumes of international shipping, rising demand for aquaculture products, and growth in the global aquarium trade, are accelerating invasive alien species spread worldwide. These threats are especially pressing amid climate and biodiversity crises. However, global and national biosecurity systems are poorly prepared to respond because of fragmented research and policy environments, that often fail to account for risks across sectors or across stakeholder needs and fail to recognize similarities in the processes underpinning biological invasions. In the present article, we illustrate the complex network of links between biosecurity threats across human, animal, plant, and environment sectors and propose a universal approach to risk assessment. One Biosecurity is a holistic, interdisciplinary approach that minimizes biosecurity risks across human, animal, plant, algal, and ecosystem health and is critical to reduce redundancy and increase cross-sectoral cohesion to improve policy, management, and research in aquatic biosecurity.

The impacts of animal agriculture on One Health-Bacterial zoonosis, antimicrobial resistance, and beyond

The industrialization of animal agriculture has undoubtedly contributed to the improvement of human well-being by increasing the efficiency of food animal production. At the same time, it has also drastically impacted the natural environment and human society. The One Health initiative emphasizes the interdependency of the health of ecosystems, animals, and humans. In this paper, we discuss some of the most profound consequences of animal agriculture practices from a One Health perspective. More specifically, we focus on impacts to host-microbe interactions by elaborating on how modern animal agriculture affects zoonotic infections, specifically those of bacterial origin, and the concomitant emergence of antimicrobial resistance (AMR). A key question underlying these deeply interconnected issues is how to better prevent, monitor, and manage infections in animal agriculture. To address this, we outline approaches to mitigate the impacts of agricultural bacterial zoonoses and AMR, including the development of novel treatments as well as non-drug approaches comprising integrated surveillance programs and policy and education regarding agricultural practices and antimicrobial stewardship. Finally, we touch upon additional major environmental and health factors impacted by animal agriculture within the One Health context, including animal welfare, food security, food safety, and climate change. Charting how these issues are interwoven to comprise the complex web of animal agriculture's broad impacts on One Health will allow for the development of concerted, multidisciplinary interventions which are truly necessary to tackle these issues from a One Health perspective.

Genetic relatedness and diversity of Capillaria species infecting bayad (Bagrus bajad) in upper Egypt

BACKGROUND

This study investigates the genetic characteristics of Capillaria isolates from the infected fish, Bagrus bajad, and their relation to human Capillaria philippinensis using Random Amplified Polymorphic DNA (RAPD-PCR) analysis. Fifteen fish Capillaria were isolated and compared to identified human C. philippinensis using six primers: M-are, M-1, G-7, G-11, G-15, and G-18.

RESULTS

All six primers successfully amplified DNA, highlighting their efficacy in distinguishing between human and fish Capillaria isolates. The analysis revealed distinctive banding patterns between fish and human isolates, with variations in size and number of DNA fragments. Additionally, genetic similarity analysis showed intriguing patterns of relatedness, with certain pairs exhibiting high similarity percentages. Comparative assessment of RAPD polymorphism demonstrated consistent findings of 100% polymorphism across all primers. The Unweighted Pair Group Method with Arithmetic Mean Algorithm (UPGMA) evaluated the closest relationship between human and fish isolates. These results underscore the utility of RAPD analysis in delineating the genetic diversity among Capillaria isolates from different hosts.

CONCLUSION

Overall, this study contributes to our understanding of the genetic variability and relatedness among Capillaria isolates, shedding light on their evolutionary dynamics and zoonotic potential.

Occurrence, molecular characterization, and antimicrobial susceptibility of sorbitol non-fermenting Escherichia coli in lake water, fish and humans in central Oromia, Ethiopia

Contaminated lake water and fish can be sources of bacterial pathogens of public health concern, including pathogenic E. coli. Within Ethiopia, specifically, Central Oromia, raw fish consumption is a common practice. Although there are few reports on occurrence of E. coli O157 in fish destined for human consumption and children under five years, information on the transmission pathways of E. coli O157 and other sorbitol non-fermenting (SN-F) E. coli from water-to-fish-to-human, and their virulence factors and antimicrobial resistant determinants along the fish supply chain is lacking. The study aimed to investigate the occurrence, molecular characteristics, and antimicrobial susceptibility of E. coli O157 and other SN-F E. coli strains in fish, lake water and humans in central Oromia, Ethiopia. A total of 750 samples (450 fish samples, 150 water samples, 150 human stool samples) were collected from five lakes and three health facilities. The samples were processed following the standard protocol recommended by European Food Safety Authority and Kirby-Bauer disc diffusion method for detection of the bacteria, and antimicrobial susceptibility tests, respectively. Molecular characterization of presumptive isolates was performed using Whole-Genome Sequencing (WGS) for serotyping, determination of virulence factors, antimicrobial resistance traits, and genetic linkage of the isolates. Overall, 3.9% (29/750) of the samples had SN-F E. coli; of which 6.7% (n = 10), 1.8% (n = 8) and 7.3% (n = 11) were retrieved from water, fish, and diarrheic human patients, respectively. The WGS confirmed that all the isolates were SN-F non-O157: H7 E. coli strains. We reported two new E. coli strains with unknown O-antigen from fish and human samples. All the strains have multiple virulence factors and one or more genes encoding for them. Genetic relatedness was observed among strains from the same sources (water, fish, and humans). Most isolates were resistant to ampicillin (100%), tetracycline (100%), cefotaxime (100%), ceftazidime (100%), meropenem (100%), nalidixic acid (93.1%) and sulfamethoxazole/trimethoprim (79.3%). Majority of the strains were resistant to chloramphenicol (58.6%) and ciprofloxacin (48.3%), while small fraction showed resistance to azithromycin (3.45%). Isolates had an overall MDR profile of 87.5%. Majority, (62.1%; n = 18) of the strains had acquired MDR traits. Genes encoding for mutational resistance and Extended-spectrum beta-lactamases (ESBL) were also detected. In conclusion, our study revealed the occurrence of virulent and MDR SN-F E. coli strains in water, fish, and humans. Although no genetic relatedness was observed among strains from various sources, the genomic clustering among strains from the same sources strongly suggests the potential risk of transmission along the supply chain at the human-fish-environment interface if strict hygienic fish production is not in place. Further robust genetic study of the new strains with unknown O-antigens, and the epidemiology of SN-F E. coli is required to elucidate the molecular profile and public health implications of the pathogens.

Cryptosporidium and agriculture: A review

Cryptosporidiosis is a significant contributor to global foodborne and waterborne disease burden. It is a widespread cause of diarrheal diseases that affect humans and animals worldwide. Agricultural environments can become a source of contamination with Cryptosporidium species through faecal material derived from humans and animals. This review aims to report the main findings of scientific research on Cryptosporidium species related to various agricultural sectors, and highlights the risks of cryptosporidiosis in agricultural production, the contamination sources, the importance of animal production in transmission, and the role of farmed animals as hosts of the parasites. Agricultural contamination sources can cause water pollution in groundwater and different surface waters used for drinking, recreational purposes, and irrigation. The application of contaminated manure, faecal sludge management, and irrigation with inadequately treated water are the main concerns associated with foodborne and waterborne cryptosporidiosis related to agricultural activities. The review emphasizes the public health implications of agriculture concerning the transmission risk of Cryptosporidium parasites and the urgent need for a new concept in the agriculture sector. Furthermore, the findings of this review provide valuable information for developing appropriate measures and monitoring strategies to minimize the risk of infection.

Potential Fungal Zoonotic Pathogens in Cetaceans: An Emerging Concern

Over 60% of emerging infectious diseases in humans are zoonotic, often originating from wild animals. This long-standing ecological phenomenon has accelerated due to human-induced environmental changes. Recent data show a significant increase in fungal infections, with 6.5 million cases annually leading to 3.7 million deaths, indicating their growing impact on global health. Despite the vast diversity of fungal species, only a few are known to infect humans and marine mammals. Fungal zoonoses, especially those involving marine mammals like cetaceans, are of global public health concern. Increased human-cetacean interactions, in both professional and recreational settings, pose risks for zoonotic disease transmission. This review focuses on the epidemiology, clinical manifestations, and zoonotic potential of major fungal pathogens shared in humans and cetaceans, highlighting their interspecies transmission capability and the challenges posed by antifungal resistance and environmental changes. It underscores the need for enhanced awareness and preventative measures in high-risk settings to protect public health and marine ecosystems.

Helicobacter pullorum and Helicobacter canadensis: Etiology, pathogenicity, epidemiology, identification, and antibiotic resistance implicating food and public health

Nowadays, it is well-established that the consumption of poultry meat, especially chicken meat products has been drastically increasing. Even though more attentions are being paid to the major foodborne pathogens, it seems that scientists in the area of food safety and public health would prefer tackling the minor food borne zoonotic emerging or reemerging pathogens, namely Helicobacter species. Recently, understanding the novel aspects of zoonotic Enterohepatic Helicobacter species, including pathogenesis, isolation, identification, and genomic features is regarded as a serious challenge. In this regard, considerable attention is given to emerging elusive zoonotic Enterohepatic Helicobacter species, comprising Helicobacter pullorum and Helicobacter canadensis. In conclusion, the current review paper would attempt to elaborately summarize and somewhat compare the etiology, pathogenesis, cultivation process, identification, genotyping, and antimicrobial resistance profile of both H. pullorum and H. Canadensis. Further, H. pullorum has been introduced as the most significant food borne pathogen in chicken meat products.

Occurrence and First Molecular Characterization of Spinitectus notopteri Karve et Naik, 1951, Infected Bronze Featherback (Notopterus notopterus) in India

PURPOSE

The nematode genus Spinitectus Fourment, 1883, comprises species that are mainly parasitic on freshwater and marine fishes. However, our knowledge of the distribution and molecular identification of Spinitectus spp. in the Indian region is rather limited. This study aims to fill this gap in our knowledge using molecular data as evidence for Spinitectus species characterization.

METHODS

Bronze featherback were obtained opportunistically from the fish markets of district Muzaffarnagar (29.4727° N, 77.7085° E), Uttar Pradesh, India. Nematode species collected from the gastrointestinal tract were characterized morphologically and molecularly. Partial sequences of the ribosomal 18S rRNA gene were used for molecular characterization of the present specimens.

RESULTS

The current study represented molecular analysis that determined the presence of the species Spinitectus notopteri Karve et Naik, 1951. The sequences obtained were closely related to representatives of the family Rhabdochonidae.

CONCLUSION

This first molecular exploration of S. notopteri Karve et Naik, 1951, in the GenBank database and for any species of Spinitectus from India indicates a lack of genetic data for parasitic nematodes.

Tracking antimicrobial resistance indicator genes in wild flatfish from the English Channel and the North Sea area: A one health concern

Antimicrobial resistance (AMR) is a burgeoning environmental concern demanding a comprehensive One Health investigation to thwart its transmission to animals and humans, ensuring food safety. Seafood, housing bacterial AMR, poses a direct threat to consumer health, amplifying the risk of hospitalization, invasive infections, and death due to compromised antimicrobial treatments. The associated antimicrobial resistance genes (ARGs) in diverse marine species can amass and transmit through various pathways, including surface contact, respiration, and feeding within food webs. Our research, focused on the English Channel and North Sea, pivotal economic areas, specifically explores the occurrence of four proposed AMR indicator genes (tet(A), blaTEM, sul1, and intI1) in a benthic food web. Analyzing 350 flatfish samples' skin, gills, and gut, our quantitative PCR (qPCR) results disclosed an overall prevalence of 71.4% for AMR indicator genes. Notably, sul1 and intI1 genes exhibited higher detection in fish skin, reaching a prevalence of 47.5%, compared to gills and gut samples. Proximity to major European ports (Le Havre, Dunkirk, Rotterdam) correlated with increased AMR gene frequencies in fish, suggesting these ports' potential role in AMR spread in marine environments. We observed a broad dispersion of indicator genes in the English Channel and the North Sea, influenced by sea currents, maritime traffic, and flatfish movements. In conclusion, sul1 and intI1 genes emerge as robust indicators of AMR contamination in the marine environment, evident in seawater and species representing a benthic food web. Further studies are imperative to delineate marine species' role in accumulating and transmitting AMR to humans via seafood consumption. This research sheds light on the urgent need for a concerted effort in comprehending and mitigating AMR risks in marine ecosystems within the context of One Health.

Photocatalytic inactivation mechanism of nano-BiPO4 against Vibrio parahaemolyticus and its application in abalone

Vibrio parahaemolyticus (V. parahaemolyticus) is the main pathogenic bacteria in seafood that can cause serious food-borne illness. The annual incidence of V. parahaemolyticus infection in the United States exceeds 45,000 cases, indicating there are potential shortcomings in seafood sterilization techniques. Meanwhile, the ongoing emergence of antibiotic-resistant strains highlights the urgent need for novel bacteriostatic strategies to eliminate V. parahaemolyticus. Nano-BiPO4 is a semiconductor with high H2O2 production efficiency and has potential for photocatalytic bacterial inactivation. But the effectiveness and mechanism of BiPO4 photocatalytic inactivation of V. parahaemolyticus has not been reported. In this study, nano-BiPO4 synthesized in pure water (P1) was found to exhibit optimal H2O2 production efficiency (1203 μmol h-1g-1) and antibacterial activity (in 0.8 g/L). Under UV light irradiation, P1 induced alterations in bacterial cell morphology, elevation in intracellular levels of ROS, H2O2, O2-, GSSG and MDA, and reduction in GSH level. Meanwhile, metabolomic analysis revealed that P1 stimulates the arginine biosynthesis, TCA cycle and alanine, aspartate and glutamate metabolism. These abnormal changes in the oxidative stress indicators and metabolic pathways proved that the bacterial damage was related to the H2O2 produced by nano-BiPO4 photocatalysis. Moreover, sliced abalone and hemolysis assay were used to demonstrate the applicability and biosafety of P1. This study provides theoretical support for exploring nano-BiPO4 as a bacterial inhibitor against V. parahaemolyticus.

Phenotypic characteristics and immune response of Procypris merus following challenge with aquatic isolate of Klebsiella pneumoniae

Currently, aquaculture is a relatively mature industry; however, disease problems are continuously threatening the industry and hindering its development to a certain extent. Klebsiella pneumoniae is one of the zoonotic bacteria widely present in different hosts and has caused some degree of harm to the aquaculture industry, posing a potential threat to the water environment and indirectly also affecting human food safety issues. In this study, K. pneumoniae was isolated from the aquaculture environment, named as ELD, and subjected to pathogenic and immunological related studies. The results of the study showed that the strain carries at least four virulence-related genes, magA, wabG, ureA and uge, and has developed resistance to at least seven antibacterial drugs, such as amoxicillin, doxycycline, rifampicin, and so on. Moreover, the strain is highly pathogenic and is capable of causing systemic clinical foci in Procypris merus. In addition, after infection with K. pneumoniae, the expression of IL-1β, IL-8, HSP70 and C2 was upregulated in P. merus as a whole, whereas the expression of TNF-α did not change significantly in any of the tissues, which might be a kind of immune response of P. merus against K. pneumoniae infection. This study provides an important theoretical basis for the in-depth exploration of the pathogenic mechanism of K. pneumoniae in fish and the immune response that occurs after the disease is contracted in fish, as well as theoretical support for the development of effective preventive and therapeutic strategies against K. pneumoniae-infected aquatic animals in the future.

Edwardsiella tarda Causing Septicemia in a Wild Crested Ibis (Nipponia nippon)

An adult Crested Ibis (Nipponia nippon) was found moribund in the Qinling area of China. Postmortem examination and histopathological analysis revealed lung inflammation and multi-organ hemorrhage. Bacterial isolation and whole-genome sequencing confirmed Edwardsiella tarda infection.

Stakeholder attitudes and perspectives on wildlife disease surveillance as a component of a One Health approach in Thailand

Coordinated wildlife disease surveillance (WDS) can help professionals across disciplines effectively safeguard human, animal, and environmental health. The aims of this study were to understand how WDS in Thailand is utilized, valued, and can be improved within a One Health framework. An online questionnaire was distributed to 183 professionals (55.7% response rate) across Thailand working in wildlife, marine animal, livestock, domestic animal, zoo animal, environmental, and public health sectors. Twelve semi-structured interviews with key professionals were then performed. Three-quarters of survey respondents reported using WDS data and information. Sectors agreed upon ranking disease control (76.5% of respondents) as the most beneficial outcome of WDS, while fostering new ideas through collaboration was valued by few participants (2.0%). Accessing data collected by one's own sector was identified as the most challenging (50%) yet least difficult to improve (88.3%). Having legal authority to conduct WDS was the second most frequently identified challenge. Interviewees explained that legal documentation required for cross-institutional collaborations posed a barrier to efficient communication and use of human resources. Survey respondents identified allocation of human resources (75.5%), adequate budget (71.6%), and having a clear communication system between sectors (71.6%) as highest priority areas for improvement to WDS in Thailand. Authorization from administrative officials and support from local community members were identified as challenges during in-person interviews. Future outreach may be directed toward these groups. As 42.9% of marine health professionals had difficulty knowing whom to contact in other sectors and 28.4% of survey respondents indicated that communication with marine health professionals was not applicable to their work, connecting the marine sector with other sectors may be prioritized. This study identifies priorities for addressing current challenges in the establishment of a general WDS system and information management system in Thailand while presenting a model for such evaluation in other regions.

A novel report on the emerging and zoonotic neurotropic fungus Trichosporon japonicum in the brain tissue of the endangered Brazilian guitarfish (Pseudobatos horkelii) off the southeastern coast of Brazil

Yeast infections have gained significant attention in the field of marine biology in recent years. Among the broad diversity of marine organisms affected by these infections, elasmobranchs (sharks and rays) have emerged as highly susceptible, due to climate change effects, such as increasing water temperatures and pollution, which can alter the composition and abundance of fungal communities. Additionally, injuries, or compromised immune systems resulting from pollution or disease may increase the likelihood of fungal infections in elasmobranchs. Studies are, however, still lacking for this taxonomic group. In this context, this study aimed to screen yeast species in cell cultures obtained from the brain of artisanally captured Pseudobatos horkelii, a cartilaginous fish that, although endangered, is highly captured and consumed worldwide. Fungi were isolated during an attempt to establish primary cultures of elasmobranch neural cells. Culture flasks were swabbed and investigated using morphological, phenotypic, and molecular techniques. Two isolates of the emerging opportunistic pathogen Trichosporon japonicum were identified, with high scores (1.80 and 1.85, respectively) by the MALDI-ToF technique. This is the first report of the basidiomycetous yeast T. japonicum in Pseudobatos horkelii in Brazil. This finding highlights the need for further research to determine the potential impact on elasmobranch health, ecology, as well as on commercial fisheries.

Microbial Pathogens in Aquaponics Potentially Hazardous for Human Health

The union of aquaculture and hydroponics is named aquaponics-a system where microorganisms, fish and plants coexist in a water environment. Bacteria are essential in processes which are fundamental for the functioning and equilibrium of aquaponic systems. Such processes are nitrification, extraction of various macro- and micronutrients from the feed leftovers and feces, etc. However, in aquaponics there are not only beneficial, but also potentially hazardous microorganisms of fish, human, and plant origin. It is important to establish the presence of human pathogens, their way of entering the aforementioned systems, and their control in order to assess the risk to human health when consuming plants and fish grown in aquaponics. Literature analysis shows that aquaponic bacteria and yeasts are mainly pathogenic to fish and humans but rarely to plants, while most of the molds are pathogenic to humans, plants, and fish. Since the various human pathogenic bacteria and fungi found in aquaponics enter the water when proper hygiene practices are not applied and followed, if these requirements are met, aquaponic systems are a good choice for growing healthy fish and plants safe for human consumption. However, many of the aquaponic pathogens are listed in the WHO list of drug-resistant bacteria for which new antibiotics are urgently needed, making disease control by antibiotics a real challenge. Because pathogen control by conventional physical methods, chemical methods, and antibiotic treatment is potentially harmful to humans, fish, plants, and beneficial microorganisms, a biological control with antagonistic microorganisms, phytotherapy, bacteriophage therapy, and nanomedicine are potential alternatives to these methods.

Captivating Colors, Crucial Roles: Astaxanthin's Antioxidant Impact on Fish Oxidative Stress and Reproductive Performance

Fish, constantly exposed to environmental stressors due to their aquatic habitat and high metabolic rates, are susceptible to oxidative stress. This review examines the interplay between oxidative stress and fish reproduction, emphasizing the potent antioxidant properties of astaxanthin. Our primary objective is to highlight astaxanthin's role in mitigating oxidative stress during critical reproductive stages, leading to improved gamete quality, ovary development, and hormone levels. We also explore its practical applications in aquaculture, including enhanced pigmentation and overall fish health. We conducted a comprehensive literature review, analyzing studies on astaxanthin's antioxidant properties and its impact on fish reproduction. Astaxanthin, a carotenoid pigment, effectively combats reactive oxygen species, inhibiting lipid peroxidation and maintaining membrane integrity. It significantly enhances reproductive success in fish and improves overall fish health in aquaculture settings. This review reveals astaxanthin's multifaceted benefits in fish health and reproduction, offering economic advantages in aquaculture. Future research should delve into species-specific responses, optimal dosages, and the long-term effects of astaxanthin supplementation to inform sustainable aquaculture strategies.

Infection levels of Gnathostomatidae (Nematoda) larvae in commercial fishes in north-eastern Australian waters and related food safety concerns

The majority of research on the safety of marine edible fish has primarily focused on anisakid nematodes, neglecting the potential risks posed by other parasites, including those belonging to the family Gnathostomatidae. In Australia, there have been few reported cases of human infections with gnathostomatid parasites since 2011. However, due to the absence of a standardized diagnostic test in the country, it is believed that the actual number of infections is higher than reported. This study aimed to assess the occurrence and prevalence of infectious gnathostomatid parasites in selected commercial fish species in Australia. A total of 1947 marine fish from northern Australia, representing 9 families, 16 genera, and 30 species, were examined for gnathostomatid nematode infections. Overall, 12.3 % of the fish were found to be infected with at least one gnathostomatid larva. Among the species examined, the yellow-dabbled flounder (Branchypleura novaezeelandiae) exhibited the highest prevalence (83.3 %; n = 6) and the largest number of gnathostomatid larvae. The identification of the gnathostomatid larvae was confirmed as belonging to the genus Echinocephalus based on both morphological characteristics and sequence data. No significant correlation was observed between the prevalence, mean abundance, and mean intensity of infection with the length or weight of the examined fish species. Notably, several of the infected fish species are considered popular choices in the Australian market. Hence, it is imperative to raise awareness among relevant food safety authorities regarding the occurrence of these parasites. The findings from this study should be taken into consideration for the revision of current seafood safety protocols in the country.

Hepcidin and piscidin modulation and antibacterial response in gilthead seabream (Sparus aurata) infected with Vibrio harveyi

Vibriosis is an infectious disease that generates large economic losses in Mediterranean aquaculture. Vibrio harveyi is one of the marine bacteria causing this disease, it is widespread in the Mediterranean Sea and causes ulcers on the skin of the fish it infects. In addition, the skin is a route of entry and colonization of this pathogen. In this study, one group of fish was injected intraperitoneally with phosphate buffered saline (control group) and another with V. harveyi (infected group). At 4 h after injection, samples of skin mucus, blood, skin, head kidney, liver, and spleen were collected to study the immune response generated. Liver histology showed notable alterations in hepatocyte morphology, such as increased vacuolization. Bactericidal activity was measured in skin mucus and serum against V. harveyi and V. anguillarum, different changes in this activity were recorded depending on the bacteria target and sample (skin mucus or serum) used. Gene expression of genes encoding hepcidins and piscidins (antimicrobial peptides) was performed in the mentioned organs. The results indicated a different expression according to the type of AMP and the tissue studied. Hepcidin appeared involved in all tissues studied while piscidins were in the spleen. In this study we have integrated hepcidin-piscidin modulation with the effects of infection on skin mucosa, serum and hepatocyte morphology. Knowing the changes produced in all these parameters improves the understanding of the infection in the first hours in sea bream and could have applications in the diagnosis or treatment of vibriosis in fish farms.

Intestinal Obstruction for Anisakiasis: Surgical and Physical Therapy Treatment

Anisakiasis, a zoonotic disease that can lead to small intestine obstruction, has seen a significant rise in Spain. The country has become the first in Europe with an annual incidence of 8000 cases, primarily due to the popularity of consuming exotic dishes of undercooked or raw fish and the impact of climate change. The clinical presentation of anisakiasis can mimic symptoms of acute appendicitis or intestinal obstruction, leading to potential misdiagnosis. This case report describes a 37-year-old patient with no significant medical history who presented abdominal distension and intense pain in the right lower quadrant. The patient underwent surgery and received physiotherapy treatment, including therapeutic exercises and pulsed-pressure myofascial vacuum therapy, to facilitate functional recovery. The increasing incidence of anisakiasis in Spain underscores the need to consider it in the differential diagnosis of digestive diseases, given the high consumption of poorly prepared or raw fish in the region.

Irradiation as a Promising Technology to Improve Bacteriological and Physicochemical Quality of Fish

Fish is an excellent source of protein and other essential minerals and vitamins; nevertheless, several food-borne disease outbreaks have been linked to the consumption of different types of fish. Therefore, we aimed to overcome these health threats by evaluating gamma radiation as a good fish preservation method. The aerobic plate count (APC), identification of most common pathogenic bacteria, organoleptic properties, proximate composition, and other chemical evaluations were detected in both untreated and gamma-treated fish. The overall grades of organoleptic evaluations ranged from good to very good. Fortunately, the overall chemical analysis of all examined fish samples was accepted. For the untreated fish samples, the APC was within and above the permissible limit (5 × 10⁷ CFU/g). Pathogenic bacteria were detected with a high prevalence rate, especially S. aureus, which was found in high percentages among examined untreated fish samples. Regarding the treated fish samples, APC and pathogenic bacterial counts were reduced in a dose-dependent manner, and the irradiation at dose 5 KGy resulted in complete eradication of the aerobic plate count (not detectable) with a mean reduction percentage equal to 100%. However, gamma irradiation has no significant effect on proximate composition; particularly, carbohydrates, proteins, and lipids were not significantly affected by low and medium doses of radiation. Therefore, gamma irradiation is a highly effective fish preservation method without any effect on fish quality. Additionally, gamma irradiation as a cold process is an attractive technology for solving the problem arising from fish-borne pathogens, and it has been purposed in this study as a cheap and safe method for reducing microbial contamination of fish.

Plerocercoids of Adenocephalus pacificus in Argentine hakes: Broad distribution, low zoonotic risk

Adenocephalus pacificus is a tapeworm parasitic of marine mammals and the main agent of human diphylobothriosis caused by consumption of raw or undercooked marine fishes, being considered as a reemerging disease. Despite having a broad distribution in marine mammals in both hemispheres, plerocercoid larvae in fish have only been reported in the Pacific Ocean, in Peruvian waters, from where most human cases are known. In Argentine waters larval stages of Diphyllobothriidae have been recorded in Merluccius hubbsi, a main fish resource mostly exported frozen, headed and gutted (H&G) or as fillets; therefore, the possible presence of A. pacificus in edible products, and the extent of the risk of parasitism for humans becomes of health and commercial relevance. With the aim of detecting and identifying potentially zoonotic diphyllobothriids and quantifying infection levels in viscera and fillets of hakes, 43 entire fish, 471 H&G, and 942 fillets obtained from research cruises in 2019 and 2021 from the southern Argentine Sea (44-53°S; 63-68°W) were examined by transillumination and under stereoscopic microscopy. Plerocercoids were recovered at low prevalence and mean abundance in entire fish (13.95 % and 0.35) and H&G fish (2.76 % and 0.03) but no larval worms were found adhered to musculature or peritoneum, furthermore, no larvae were found in the fillets. Larvae were genetically identified, based on sequences of the large subunit ribosomal RNA nuclear gene (lsrDNA) and the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene, as members of A. pacificus, representing the first report of this species in a fish host outside South American Pacific coasts. No spatial nor bathymetric patterns in parasite burdens were observed across sampling sites, but prevalence increased with fish size. The recorded low parasite burdens, the absence of infective stages in fillets and the fact that most products are commercialized deeply frozen, diminish the risk of parasitism for consumers to a minimum. However, the identification of this zoonotic agent and the assessment of its distribution in fish products are a first indispensable step for the design of efficient and suitable measures, such as freezing or cooking meet, to ensure the prevention of human infections.

Misunderstandings and misinterpretations: Antimicrobial use and resistance in salmon aquaculture

The exponential growth of aquaculture over the past 30 years has been accompanied by a parallel increase in the use of antimicrobials. This widespread use has had negative effects on animal, human and environmental health and affected the biodiversity of the environments where aquaculture takes place. Results showing these harmful effects have been resisted and made light of by the aquaculture industry and their scientific supporters through introduction of misunderstandings and misinterpretations of concepts developed in the evolution, genetics, and molecular epidemiology of antimicrobial resistance. We focus on a few of the most obvious scientific shortcomings and biases of two recent attempts to minimise the negative impacts of excessive antimicrobial use in Chilean salmon aquaculture on human and piscine health and on the environment. Such open debate is critical to timely implementation of effective regulation of antimicrobial usage in salmon aquaculture in Chile, if the negative local and worldwide impacts of this usage are to be avoided.