Fish and fisheries in Bangladesh: Zoonotic risks, AMR, and environmental challenges under a one health perspective.

Bangladesh's fisheries sector, central to national nutrition, food security, and rural livelihoods, is increasingly threatened by the convergence of zoonotic pathogens, antimicrobial resistance (AMR), and environmental degradation. Using a One Health framework, this review synthesizes evidence from 87 peer-reviewed articles, institutional reports, and regional studies to demonstrate how interactions among aquatic ecosystems, farmed and wild fish populations, and human communities drive the emergence and transmission of disease. Zoonotic parasites including trematodes, cestodes, nematodes, and protozoa persist through contaminated water, inadequate market hygiene, and exposure to domestic and wild animals. Aquaculture systems are further burdened by zoonotic bacteria (e.g., Vibrio spp., Aeromonas spp., and Mycobacterium spp.) and microsporidian parasites (e.g., Enterocytozoon spp.), together posing significant occupational and foodborne risks. Emerging fungal pathogens, notably Saprolegnia spp. and Aphanomyces invadans, intensify disease burdens under poor farm management and environmentally stressed conditions. Critical contamination pathways, industrial and agricultural runoff, cross-contamination in fish markets, unregulated chemical use, and weak biosecurity link aquatic pollution with human and animal health outcomes. The introduction of non-native fish species (e.g., tilapia, pangas, carp) and the expanding ornamental fish trade further amplify pathogen risks, facilitating the silent spread of bacterial, parasitic, and fungal agents with zoonotic potential. Climate change, biodiversity loss, and socioeconomic vulnerabilities exacerbate these pressures by destabilizing aquatic ecosystems, reducing resilience, and accelerating AMR dissemination across aquatic, human, and livestock interfaces. By integrating insights from parasitology, microbiology, epidemiology, and environmental science, this review underscores the urgent need for coordinated surveillance, diagnostic capacity, regulatory enforcement, and risk communication strategies. Embedding One Health and climate-smart approaches into fisheries governance is essential to mitigate zoonotic hazards, safeguard food safety, and ensure the long-term sustainability of Bangladesh's aquaculture sector under accelerating environmental change.