Intensification of fragility: Poultry production and distribution in Bangladesh and its implications for disease risk

Modelling the transmission dynamics of H9N2 avian influenza viruses in a live bird market

H9N2 avian influenza viruses (AIVs) are a major concern for the poultry sector and human health in countries where this subtype is endemic. By fitting a model simulating H9N2 AIV transmission to data from a field experiment, we characterise the epidemiology of the virus in a live bird market in Bangladesh. Many supplied birds arrive already exposed to H9N2 AIVs, resulting in many broiler chickens entering the market as infected, and many indigenous backyard chickens entering with pre-existing immunity. Most susceptible chickens become infected within one day spent at the market, owing to high levels of viral transmission within market and short latent periods, as brief as 5.3 hours. Although H9N2 AIV transmission can be substantially reduced under moderate levels of cleaning and disinfection, effective risk mitigation also requires a range of additional interventions targeting markets and other nodes along the poultry production and distribution network.

EPINEST, an agent-based model to simulate epidemic dynamics in large-scale poultry production and distribution networks

The rapid intensification of poultry production raises important concerns about the associated risks of zoonotic infections. Here, we introduce EPINEST (EPIdemic NEtwork Simulation in poultry Transportation systems): an agent-based modelling framework designed to simulate pathogen transmission within realistic poultry production and distribution networks. We provide example applications to broiler production in Bangladesh, but the modular structure of the model allows for easy parameterization to suit specific countries and system configurations. Moreover, the framework enables the replication of a wide range of eco-epidemiological scenarios by incorporating diverse pathogen life-history traits, modes of transmission and interactions between multiple strains and/or pathogens. EPINEST was developed in the context of an interdisciplinary multi-centre study conducted in Bangladesh, India, Vietnam and Sri Lanka, and will facilitate the investigation of the spreading patterns of various health hazards such as avian influenza, Campylobacter, Salmonella and antimicrobial resistance in these countries. Furthermore, this modelling framework holds potential for broader application in veterinary epidemiology and One Health research, extending its relevance beyond poultry to encompass other livestock species and disease systems.

Prevalence and genetic characterization of Campylobacter from clinical poultry cases in China

IMPORTANCE

Campylobacter is a major cause of campylobacteriosis worldwide, and poultry is the main reservoir for its transmission. Campylobacter was generally considered to be a harmless commensal organism in poultry without pathogenic properties. However, it was proposed that a Campylobacter-like organism may be the cause of vibrionic hepatitis, which poses a significant public health risk. The occurrence and epidemiology of Campylobacter in healthy poultry have been studied systematically, but little is known about the epidemiology of Campylobacter isolates from diseased poultry in China. Therefore, this study determined the prevalence and molecular characterization of Campylobacter from diseased chickens, ducks, and geese in Yangzhou Veterinary Hospital between December 2016 and September 2017, which was critical for improving the diagnosis and prevention of Campylobacter infections.

Method in limbo? Theoretical and empirical considerations in using thematic analysis by veterinary and One Health researchers

This article spans a number of theoretical, empirical and practice junctures at the intersection of human and animal medicine and the social sciences. We discuss the way thematic analysis, a qualitative method borrowed from the social sciences, is being increasingly used by veterinary and One Health researchers to investigate a range of complex issues. By considering theoretical aspects of thematic analysis, we expand our discussion to question whether this tool, as well as other social science methods, is currently being used appropriately by veterinary and human health researchers. We suggest that additional engagement with social science theory would enrich research practices and improve findings. We argue that considerations of 'big theory' - ontological and epistemological positionings of the researcher - and 'small(er)' theory, the specific social theory in which research is situated, are both necessary. Our point of departure is that scientific discourse is not merely construction or ideology but a unique and continuing arena of debate, in part at least because of the elevation of self-criticism to a central tenet of its practice. We argue for further engagement with the core ideas and concepts outlined above and discuss them in what follows. In particular, and by way of focusing the point, we suggest that for veterinary, One Health, and human medical researchers to use thematic analysis to its maximum potential they should be encouraged to engage with both broader socio-economic theories and with questions of ontology and epistemology.

Mapping of dressed and processed poultry products in Bangladesh: Identifying the food safety risks for policy intervention

Bangladesh's commercial poultry production is growing rapidly, including the commercial processing of poultry. This expansion of poultry processing plants is fueled by the belief that this sub-sector provides safer food and has less food-borne disease risks compared to traditional live bird markets (LBMs). The purpose of this study is to describe Bangladesh's dressed and processed poultry production and distribution network (PDN), identify what and where quality control occurs, and suggest where improvements could be made. Engaging with PDN for dressed and processed poultry, we used in-depth interviews with key informants to identify the stakeholders involved and their connections with other poultry PDNs. In addition, we mapped out the supply and distribution of dressed and processed poultry and quality control processes occurring throughout the network. We argue that dressed and processed poultry PDNs are closely connected with traditional PDNs such as LBMs, with multiple crossover points between them. Also, there is a lack of consistency in quality control testing and a lack of meat traceability. Consequently, perceptions of dressed and processed poultry being safer than birds from LBMs needs to be treated with caution. Otherwise, unsubstantiated consumer confidence in dressed poultry may inadvertently increase the risk of food-borne diseases from these products.

Annual trading patterns and risk factors of avian influenza A/H5 and A/H9 virus circulation in turkey birds (Meleagris gallopavo) at live bird markets in Dhaka city, Bangladesh

The impacts of the avian influenza virus (AIV) on farmed poultry and wild birds affect human health, livelihoods, food security, and international trade. The movement patterns of turkey birds from farms to live bird markets (LBMs) and infection of AIV are poorly understood in Bangladesh. Thus, we conducted weekly longitudinal surveillance in LBMs to understand the trading patterns, temporal trends, and risk factors of AIV circulation in turkey birds. We sampled a total of 423 turkeys from two LBMs in Dhaka between May 2018 and September 2019. We tested the swab samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We used exploratory analysis to investigate trading patterns, annual cyclic trends of AIV and its subtypes, and a generalized estimating equation (GEE) logistic model to determine the factors that influence the infection of H5 and H9 in turkeys. Furthermore, we conducted an observational study and informal interviews with traders and vendors to record turkey trading patterns, demand, and supply and turkey handling practices in LBM. We found that all trade routes of turkey birds to northern Dhaka are unidirectional and originate from the northwestern and southern regions of Bangladesh. The number of trades from the source district to Dhaka depends on the turkey density. The median distance that turkey was traded from its source district to Dhaka was 188 km (Q1 = 165, Q3 = 210, IQR = 45.5). We observed seasonal variation in the median and average distance of turkey. The qualitative findings revealed that turkey farming initially became reasonably profitable in 2018 and at the beginning of 2019. However, the fall in demand and production in the middle of 2019 may be related to unstable market pricing, high feed costs, a shortfall of adequate marketing facilities, poor consumer knowledge, and a lack of advertising. The overall prevalence of AIV, H5, and H9 subtypes in turkeys was 31% (95% CI: 26.6-35.4), 16.3% (95% CI: 12.8-19.8), and 10.2% (95% CI: 7.3-13.1) respectively. None of the samples were positive for H7. The circulation of AIV and H9 across the annual cycle showed no seasonality, whereas the circulation of H5 showed significant seasonality. The GEE revealed that detection of AIV increases in retail vendor business (OR: 1.71; 95% CI: 1.12-2.62) and the bird's health status is sick (OR: 10.77; 95% CI: 4.31-26.94) or dead (OR: 11.33; 95% CI: 4.30-29.89). We also observed that winter season (OR: 5.83; 95% CI: 2.80-12.14) than summer season, dead birds (OR: 61.71; 95% CI: 25.78-147.75) and sick birds (OR 8.33; 95% CI: 3.36-20.64) compared to healthy birds has a higher risk of H5 infection in turkeys. This study revealed that the turkeys movements vary by time and season from the farm to the LBM. This surveillance indicated year-round circulation of AIV with H5 and H9 subtypes in turkey birds in LBMs. The seasonality and health condition of birds influence H5 infection in birds. The trading pattern of turkey may play a role in the transmission of AIV viruses in the birds. The selling of sick turkeys infected with H5 and H9 highlights the possibility of virus transmission to other species of birds sold at LBMs and to people.

Mapping chicken production and distribution networks in Vietnam: An analysis of socio-economic factors and their epidemiological significances

The growing chicken industry in Viet Nam has an increasingly important contribution to the country's food security, but its development requires careful planning to prevent disease risks. This study characterizes the chicken production and distribution networks in Vietnam and identifies potential factors that could promote disease emergence and transmission. Qualitative data were collected from interviews with 29 key informants from five stakeholder groups representing the main nodes from chicken production and distribution networks (PDN). Three main networks were identified based on production type: a colored broiler and spent hen network, a white (or exotic) broiler network, and an egg network. Colored chickens and spent hens are the most preferred commodity by vietnamese consumers and their PDN is composed of production units differing in their scale and management and with long distribution chains involving numerous small-scale independent stakeholders. Live bird markets plays a central role in this network, which is driven by consumers' preference for live chickens. The white chicken network presents an important duality, as it is composed of both a large number of independent household farms and traders operating independently with little chain coordination, and of large farms contracted by vertically-integrated companies. The egg PDN was the most organized network, being mostly controlled by large vertically-integrated companies. High level specialization and diversification of stakeholders is found in all three networks. Stakeholders' perceptions of the main factors promoting disease risk along the PDN were the low biosecurity in household farms and live bird markets, mobile traders, the informal slaughter of birds and the management of sick birds. Findings from this study can be used to plan future studies to support food system planners in the development of safer poultry production and distribution in Vietnam.

Drivers of Antibiotic Use in Semi-Intensive Poultry Farms: Evidence from a Survey in Senegal

Antimicrobial resistance (AMR), the capacity of microbial pathogens to survive in the presence of antimicrobials, is considered one of the greatest threats to human health worldwide and is growing rapidly in importance. AMR is thought to be driven in part by the use of antimicrobials (AMU) in livestock production. AMU reduction in agriculture is therefore important, but doing so may endanger farmers' livelihoods and hamper broader food security. Understanding the drivers for farmers' antibiotics use is essential for designing interventions which avoid harming agricultural output and to safeguard farmers' economic security. In this study, we analyse AMUSE survey data from poultry farmers in Senegal to explore the effects of vaccination, attitudes towards AMR, and biosecurity practices on: AMU, animal mortality, and farm productivity. We found that farmers with more "AMR-aware" attitudes may be less likely to use antibiotics in healthy birds. Stronger on-farm biosecurity was associated with less use of antibiotics in healthy birds, and in some specifications was linked to higher broiler productivity. Vaccination and AMU were both higher in farms with a higher disease prevalence, and both factors appeared conducive to higher broiler productivity. Overall, there is evidence that awareness raising and biosecurity improvements could encourage prudent use of antibiotics, and that biosecurity and vaccination could to some extent replace antibiotic use as productivity-enhancing and disease management tools in broiler farms. Finally, issues of farm antimicrobial stewardship must be considered at the structural level, with farm behaviours contingent on interaction with state and private stakeholders.

Prevalence and risk factors for avian influenza virus (H5 and H9) contamination in peri-urban and rural live bird markets in Bangladesh

Avian influenza viruses (AIV) have been frequently detected in live bird markets (LBMs) around the world, primarily in urban areas, and have the ability to spillover to other species, including humans. Despite frequent detection of AIV in urban LBMs, the contamination of AIV on environmental surfaces in rural and peri-urban LBMs in Bangladesh is poorly documented. Therefore, we conducted this study to determine the prevalence of AIV subtypes within a subset of peri-urban and rural LBMs in Bangladesh and to further identify associated risk factors. Between 2017 and 2018, we collected faecal and offal samples from 200 stalls in 63 LBMs across four sub-districts. We tested the samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We performed a descriptive analysis of market cleanliness and sanitation practices in order to further elucidate the relationship between LBM biosecurity and AIV subtypes by species, sample types, and landscape. Subsequently, we conducted a univariate analysis and a generalized linear mixed model (GLMM) to determine the risk factors associated with AIV contamination at individual stalls within LBMs. Our findings indicate that practices related to hygiene and the circulation of AIV significantly differed between rural and peri-urban live bird markets. 42.5% (95% CI: 35.56-49.67) of stalls were positive for AIV. A/H5, A/H9, and A HA/Untyped were detected in 10.5% (95% CI: 6.62-15.60), 9% (95% CI: 5.42-13.85), and 24.0% (95% CI: 18.26-30.53) of stalls respectively, with no detection of A/H7. Significantly higher levels of AIV were found in the Sonali chicken strain compared to the exotic broiler, and in offal samples compared to fecal samples. In the GLMM analysis, we identified several significant risk factors associated with AIV contamination in LBMs at the stall level. These include: landscape (AOR: 3.02; 95% CI: 1.18-7.72), the number of chicken breeds present (AOR: 2.4; 95% CI: 1.01-5.67), source of birds (AOR: 2.35; 95% CI: 1.0-5.53), separation of sick birds (AOR: 3.04; 95% CI: 1.34-6.92), disposal of waste/dead birds (AOR: 3.16; 95% CI: 1.41-7.05), cleaning agent (AOR: 5.99; 95% CI: 2.26-15.82), access of dogs (AOR: 2.52; 95% CI: 1.12-5.7), wild birds observed on site (AOR: 2.31; 95% CI: 1.01-5.3). The study further revealed a substantial prevalence of AIV with H5 and H9 subtypes in peri-urban and rural LBMs. The inadequate biosecurity measures at poultry stalls in Bangladesh increase the risk of AIV transmission from poultry to humans. To prevent the spread of AIV to humans and wild birds, we suggest implementing regular surveillance at live bird markets and enhancing biosecurity practices in peri-urban and rural areas in Bangladesh.

Antibiotic usage practices and its drivers in commercial chicken production in Bangladesh

Irrational and inappropriate use of antibiotics in commercial chicken production can contribute to the development of antimicrobial resistance. We aimed to assess antibiotic usage in commercial chicken production in Bangladesh, and identify factors associated with this practice. We conducted a large-scale cross-sectional study to collect information on antibiotic usage in commercial chickens from January to May 2021. Structured interviews were conducted with 288 broiler, 288 layer and 192 Sonali (locally-produced cross-bred) farmers in 20 sub-districts across Bangladesh. The frequency of antibiotic usage, the types of antibiotics and purpose of usage were estimated for each production type. Adjusted odds ratios (aOR) were calculated to measure the association between antibiotic usage and factors related to the characteristics of the farms and farmers using multivariable logistic regression models. The proportion of farms, irrespective of their production type, reporting usage of antibiotics in the 24 hours preceding the interview was 41% (n = 314, 95% CI: 37–44%). Forty-five percent (n = 344, 41–48%) reported antibiotic usage in the last 72 hours, 86% (n = 658, 83–88%) in the last 14 days, and almost all farms, 98% (n = 753, 97–99%), had used antibiotics since the start of their production cycle. Use of antibiotics in the 24 hours preceding an interview was more frequently reported in broiler (OR 1.91, 95% CI: 1.36–2.69) and Sonali (OR 1.94, 95% CI: 1.33–2.33) than layer farms. Oxytetracycline (23–31%, depending on production type), doxycycline (18–25%), ciprofloxacin (16–26%) and amoxicillin (16–44%) were the most frequently used antibiotics. Antibiotics were reported to be used for both treatment and prophylactic purposes on most farms (57–67%). Usage of antibiotics in the 24h preceding an interview was significantly associated with the occurrence of any illnesses in chickens (aOR broiler: 41.22 [95% CI:13.63–124.62], layer: aOR 36.45[9.52–139.43], Sonali: aOR 28.47[4.97–162.97]). Antibiotic usage was mainly advised by veterinary practitioners (45–71%, depending on production type), followed by feed dealers (21–40%) and farmers (7–13%). Improvement of chicken health through good farming practices along with changes in key stakeholders (feed dealers and practitioners) attitudes towards antibiotic recommendations to farmers, may help to reduce the levels of antibiotic usage and thus contribute to mitigate antimicrobial resistance.

Farm-Level Risk Factors Associated With Avian Influenza A (H5) and A (H9) Flock-Level Seroprevalence on Commercial Broiler and Layer Chicken Farms in Bangladesh

A cross-sectional study was conducted to identify farm-level risk factors associated with avian influenza A H5 and H9 virus exposure on commercial chicken farms in Bangladesh. For broiler farms, both H5 and H9 seropositivity were associated with visits by workers from other commercial chicken farms [odds ratio (OR) for H5 = 15.1, 95% confidence interval (CI): 2.8-80.8; OR for H9 = 50.1, 95% CI: 4.5-552.7], H5 seropositivity was associated with access of backyard ducks (OR = 21.5, 95% CI: 2.3-201.1), and H9 seropositivity with a number of farm employees (OR = 9.4, 95% CI: 1.1-80.6). On layer farms, both H5 and H9 seropositivity were associated with presence of stray dogs (OR for H5 = 3.1, 95% CI: 1.1-9.1; OR for H9 = 4.0, 95% CI: 1.1-15.3), H5 seropositivity with hatcheries supplying chicks (OR = 0.0, 95% CI: 0.0-0.3), vehicles entering farms (OR = 5.8, 95% CI: 1.5-22.4), number of farm employees (OR = 5.8, 95% CI: 1.2-28.2), and burying of dead birds near farms (OR = 4.6, 95% CI: 1.2-17.3); H9 seropositivity with traders supplying feed (OR = 5.9, 95% CI: 1.0-33.9), visits conducted of other commercial poultry farms (OR = 4.7, 95% CI: 1.1-20.6), number of spent layers sold (OR = 24.0, 95% CI: 3.7-155.0), and frequency of replacing chicken droppings (OR = 28.3, 95% CI: 2.8-284.2). Policies addressing these risk factors will increase the effectiveness of prevention and control strategies reducing the risk of avian influenza on commercial chicken farms.

COVID-19 Impact on Poultry Production and Distribution Networks in Bangladesh

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.

Antibiotic Usage and Resistance in Food Animal Production: What Have We Learned from Bangladesh?

Irrational and inappropriate use of antibiotics in commercial chicken and aquaculture industries can accelerate the antibiotic resistance process in humans and animals. In Bangladesh, the growing commercial chicken and aquaculture industries are playing significantly important roles in the food value chain. It is necessary to know the antibiotic usage practices and antibiotic resistance in food animal production to design rational policies, guidelines, and interventions. We conducted a narrative review to understand the level of antibiotic usage and resistance in food animal production in Bangladesh. Information about antibiotic usage in different food animal production systems, including commercial chickens and aquaculture in Bangladesh is inadequate. Only a few small-scale studies reported that the majority (up to 100%) of the broiler and layer chicken farms used antibiotics for treating and preventing diseases. However, numerous studies reported antibiotic-resistant bacteria of public health importance in commercial chicken, fish, livestock, and animal origin food. The isolates from different pathogenic bacteria were found resistant against multiple antibiotics, including quinolones, the third or fourth generation of cephalosporins, and polymyxins. Veterinary practitioners empirically treat animals with antibiotics based on presumptive diagnosis due to inadequate microbial diagnostic facilities in Bangladesh. Intensive training is helpful to raise awareness among farmers, feed dealers, and drug sellers on good farming practices, standard biosecurity practices, personal hygiene, and the prudent use of antibiotics. Urgently, the Government of Bangladesh should develop and implement necessary guidelines to mitigate irrational use of antibiotics in food animals using a multi-sectoral One Health approach.