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.

The study was conducted to detection and determination of concentration or level of antibiotic residues in milk and egg of local and commercial farms at Chittagong during December 2011 to June 2012. A total of 400 (200 milk and 200 egg) samples were collected from local and commercial dairy cows and local scavenging and commercial poultry farms, respectively. Microbial inhibition test and thin layer chromatography were used for screening and ultra-high performance liquid chromatography was used to estimate the concentrations of antibiotic residues in samples. Tetracycline, amoxicillin, and ciprofloxacin residues were significantly (p ≤ 0.05) higher in commercial farms than local. The boiling insignificantly (p>0.05) reduced residues level in milk and egg. The average concentrations of amoxicillin residue in local milk, commercial milk, local egg, and commercial egg were 9.84 µg/ml, 56.16 µg/ml, 10.46 µg/g and 48.82 µg/g, respectively, in raw samples and were reduced to 9.81 µg/ml, 55.54 µg/ml, 10.29 µg/g, and 48.38 µg/g, respectively, after boiling. Proper maintaining of the withdrawal period and development of active surveillance system are highly recommended for public health security.

It is anticipated that a 50% to 70% increase in food productivity will be needed to feed 9 billion people by 2050. Livestock provide for about 33% of human protein consumption and 17% of total calories ( FAO, 2018). The demand for livestock products is estimated to more than double in the next 20 yr, as a result of urbanization, economic growth, and a change in consumption patterns in low- and middle-income countries (LMICs). The livestock sector represents nearly 1 billion smallholder livestock producers in developing countries and contributes 40% of agricultural Gross Domestic Product and from 2% to over 33% of household incomes. Smallholder livestock production is largely based on family farming and is key to poor rural people’s livelihoods, food security, and employment creation. Livestock provide food for household consumption, products for income generation, and quick cash when emergencies and external shocks occur (i.e., climatic conditions, diseases, and price volatility). Livestock are important assets that respond to the multiple needs of smallholders (e.g., manure, draught, and hauling power), while also having a cultural and spiritual value. Poultry and small ruminants are generally managed by and provide direct benefits to women ( Guèye, 2003; FAO, 2020; IFAD, 2020).

The COVID-19 pandemic has severely affected numerous economic sectors across the world, including livestock production. This study investigates how the pandemic has impacted the poultry production and distribution network (PDN), analyses stakeholders' changing circumstances, and provides recommendations for rapid and long-term resilience. This is based on a literature review, social media monitoring, and key informant interviews (n = 36) from across the poultry sector in Bangladesh. These included key informants from breeder farms and hatcheries, pharmaceutical suppliers, feed companies, dealers, farmers, middlemen, and vendors. We show that the poultry sector was damaged by the COVID-19 pandemic, partly as a result of the lockdown and also by rumors that poultry and their products could transmit the disease. This research shows that hardly any stakeholder escaped hardship. Disrupted production and transportation, declining consumer demand and volatile markets brought huge financial difficulties, even leading to the permanent closure of many farms. We show that the extent of the damage experienced during the first months of COVID-19 was a consequence of how interconnected stakeholders and businesses are across the poultry sector. For example, a shift in consumer demand in live bird markets has ripple effects that impact the price of goods and puts pressure on traders, middlemen, farmers, and input suppliers alike. We show how this interconnectedness across all levels of the poultry industry in Bangladesh makes it fragile and that this fragility is not a consequence of COVID-19 but has been revealed by it. This warrants long-term consideration beyond the immediate concerns surrounding the COVID-19 pandemic.