The aquaculture sector in Bangladesh is an important employer and a significant source of foreign exchange. In addition, it contributes significantly to food security due to the role of fish in peoples' diets, the most important source of protein and micronutrients. However, infectious diseases represent an important barrier to sector development due to economic losses and vulnerability of smallholders. The aim of this study was to gain an overview of the impact of infectious diseases in the aquaculture sector, and to assess the usefulness and use of impact studies in decision making for animal health management and biosecurity governance in Bangladesh. A review of scientific and grey literature on infectious disease impact in different aquaculture systems was conducted and their methodologies and findings summarised. Subsequently, interviews with 28 stakeholders from the private and public sector were conducted to enquire about decision-making structures in animal health management. The data were analysed using the framework method to allow the development of themes, by using the information, experiences and opinions inductively obtained from interviewees, deductively through the reviewed literature. Results showed a substantial socio-economic impact of infectious diseases. The numerous stakeholders involved in the decision-making process explained that key barriers to effective aquaculture health management were insufficient resources to investigate and tackle infectious aquatic animal diseases, a dearth of legislation and capacity for disease surveillance, a reliance on reactive response, and a lack of impact and evidence-based approaches for prioritising problem-solving, commonly based on anecdotal evidence. Furthermore, communication among the multiple stakeholders involved was reported to be weak. This complex situation requires a multi-level response, which should span from strengthening the knowledge of farmers and professionals in the field to the improvement of surveillance and diagnostic systems. Improved systems along with evidence on disease impact could inform the prioritisation of diseases and resource allocation for disease control in Bangladesh. Further, this evidence needs to be used to advise decisions to have a true value, for which establishing and strengthening communication pathways and processes is critical to make systematic use of the information and improve animal health management. In the light of future threats to Bangladesh such as climate change, increasing population density and demand for animal source foods, it is crucial to strengthen animal health management systems to reduce livelihoods vulnerability, food insecurity and the likelihood of disease emergence.
Indiscriminate antimicrobial use (AMU) in aquaculture to treat and prevent diseases is common and can lead to the emergence of antimicrobial-resistant micro-organisms, potentially impacting public health and connected ecosystems. This study aimed to develop a typology to classify and characterise interventions to reduce AMU in aquaculture and identify points of action. Seventeen aquaculture and animal health professionals in Asian and African countries were interviewed to gather information on characteristics of interventions in different contexts to develop a typology. Seven types of interventions were defined: (i) legislation and regulations; (ii) industry rules and standards; (iii) voluntary instruments; (iv) commercial technology and alternatives to antimicrobials; (v) on-farm management; (vi) learning and awareness-raising; and (vii) activities with co-benefits. Types were based on intervention function, scope of implementation, implementer, compulsion, strength of the intervention, AMU/antimicrobial resistance (AMR) objective and stakeholder to influence. For each type, examples were described and discussed. The most common interventions to address AMU and AMR were legislative and regulatory frameworks and voluntary instruments, including National Action Plans. Interventions addressing AMU/AMR specifically were scarce. Other interventions focused on indirect effect pathways to AMU and AMR reduction aiming to improve good aquaculture practices, disease prevention and improved management. Monitoring and evaluation of these interventions were found to be rare, only present for interventions driven by development projects and international agencies. The presented typology of existing strategies and interventions addressing AMU/AMR in aquaculture systems can guide evaluation of AMR-sensitive interventions that promote responsible AMU, and informs the design and implementation of future interventions.
Aquaculture systems are highly complex, dynamic and interconnected systems influenced by environmental, biological, cultural, socio-economic and human behavioural factors. Intensification of aquaculture production is likely to drive indiscriminate use of antibiotics to treat or prevent disease and increase productivity, often to compensate for management and husbandry deficiencies. Surveillance or monitoring of antibiotic usage (ABU) and antibiotic resistance (ABR) is often lacking or absent. Consequently, there are knowledge gaps for the risk of ABR emergence and human exposure to ABR in these systems and the wider environment. The aim of this study was to use a systems-thinking approach to map two aquaculture systems in Vietnam - striped catfish and white-leg shrimp - to identify hotspots for emergence and selection of resistance, and human exposure to antibiotics and antibiotic-resistant bacteria. System mapping was conducted by stakeholders at an interdisciplinary workshop in Hanoi, Vietnam during January 2018, and the maps generated were refined until consensus. Thereafter, literature was reviewed to complement and cross-reference information and to validate the final maps. The maps and component interactions with the environment revealed the grow-out phase, where juveniles are cultured to harvest size, to be a key hotspot for emergence of ABR in both systems due to direct and indirect ABU, exposure to water contaminated with antibiotics and antibiotic-resistant bacteria, and duration of this stage. The pathways for human exposure to antibiotics and ABR were characterised as: occupational (on-farm and at different handling points along the value chain), through consumption (bacterial contamination and residues) and by environmental routes. By using systems thinking and mapping by stakeholders to identify hotspots we demonstrate the applicability of an integrated, interdisciplinary approach to characterising ABU in aquaculture. This work provides a foundation to quantify risks at different points, understand interactions between components, and identify stakeholders who can lead and implement change.