Antimicrobial and other aquamedicine use for disease treatment in pond-based commercial tilapia farms in Bangladesh

This study addresses the limited information on use of antimicrobials and other chemical use in commercial tilapia farms in Bangladesh. A retrospective cross-sectional survey was conducted in November 2022 in the Mymensingh district, a major tilapia production hub. Nearly half of the farms (46.6%) experienced fish mortality during the last production cycle, and 75.0% of farmers did not seek professional assistance during disease outbreaks. Among those who did, 68.0% relied on chemical or drug suppliers for guidance rather than veterinary experts. Biosecurity practices were inadequate, with 98.3% not implementing four basic monitored measures: disinfection of vehicles, footwear, hands, and equipment. Awareness of antimicrobial use (AMU) risks among respondents was low, with 56.0% unaware of its negative impacts and 88.8% unfamiliar with antimicrobial resistance (AMR). Antibiotic use was low, with only 15.5% of farms reporting antibiotic treatments, primarily oxytetracycline hydrochloride (23.8%), enrofloxacin (19.0%), and erythromycin–sulphadiazine–trimethoprim (19.0%). However, other chemicals with antimicrobial properties, such as disinfectants, were more commonly applied, reported by 39.7% of farms for disease management. The use of both antimicrobial and non-antimicrobial medicine varied significantly by location, being significantly less likely observed in Tarakanda (p < 0.05) and Fulbaria (p < 0.01), suggesting location-specific differences in disease management. The presence of clinical signs was significantly associated with increased use of both antimicrobials, non-antimicrobial medicine and use of overall aquamedicine (p < 0.001), while longer cultivation durations showed a weak association with reduced AMU. Imprudent use of antimicrobials and other chemicals may pose One Health risks, including disruption of pond microbial ecosystems, AMR development, chemical residues, and occupational hazards. In-depth qualitative studies are needed to further understand and optimize antimicrobial and other chemical use practices and determine how tilapia farmers may benefit from improved biosecurity, training, and veterinary access.