Competing biosecurity and risk rationalities in the Chittagong poultry commodity chain, Bangladesh

Amplification of avian influenza virus circulation along poultry marketing chains in Bangladesh: A controlled field experiment

The prevalence of avian influenza viruses is commonly found to increase dramatically as birds are transported from farms to live bird markets. Viral transmission dynamics along marketing chains are, however, poorly understood. To address this gap, we implemented a controlled field experiment altering chicken supply to a live bird market in Chattogram, Bangladesh. Broilers and backyard chickens traded along altered (intervention) and conventional (control) marketing chains were tested for avian influenza viruses at different time points. Upon arrival at the live bird market, the odds of detecting avian influenza viruses did not differ between control and intervention groups. However, 12 h later, intervention group odds were lower, particularly for broilers, indicating that viral shedding in live bird markets resulted partly from infections occurring during transport and trade. Curtailing avian influenza virus prevalence in live bird markets requires mitigating risk in marketing chain nodes preceding chickens' delivery at live bird markets.

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.

Determinants for the presence of avian influenza virus in live bird markets in Bangladesh: Towards an easy fix of a looming one health issue

Highly pathogenic avian influenza virus subtype H5N1 endangers poultry, wildlife, and human health and is enzootic in large parts of Asia, with live bird markets (LBMs) as putative hotspots for their maintenance, amplification, and spread. To mitigate the extent of these and other avian influenza viruses (AIV) of concern, we aimed to increase our quantitative understanding of the factors determining the presence of avian influenza virus in LBM stalls. Between 2016 and 2017, we collected fecal or offal samples from 1008 stalls in 113 LBMs across the Dhaka and Rajshahi districts in Bangladesh. For each stall, samples were pooled and tested for the AIV matrix gene, followed by H5 and H9 subtyping using rRT-PCR. We detected Influenza A viral RNA in 49% of the stalls. Of the AIV positive samples, 52% and 24% were determined to be H5 and H9 viruses, respectively, which are both subtypes of considerable health concern. We used generalized linear mixed effect modelling to study AIV presence in individual stalls within LBMs as a function of 13 out of the 20 risk factors identified by FAO. We found that small and feasible improvements in cleaning and disinfection frequency, installing running water in stalls, and not mixing different breeds of chicken in the same cages had large impacts on the presence of AIV in stalls (Odds ratios 0.03-0.05). Next, cleaning vehicles used in poultry transport, not selling waterfowl with chickens in the same stall, buying stock directly from commercial farms, separating sick birds from healthy ones, and avoiding access by wild birds like house crows, also had major effects on lowering the risk of stalls having AIV (Odds ratios 0.16-0.33). These findings can be directly used in developing practical and affordable measures to reduce the prevalence of AIV in LBMs. Also, in settings with limited resources like Bangladesh, such mitigation may significantly contribute to reducing AIV circulation amongst poultry and spillover to wildlife and humans.

Live poultry markets beyond health risks: Understanding consumer preferences for live poultry in South China

Live poultry markets (LPMs) are veterinary and public health risks because of potential for zoonotic spillover of pathogens from diseased animals to humans. To control these health risks, veterinary and public health authorities in Asia, including China, have closed or restricted LPMs. In south China, however, LPM closure has been opposed or rendered infeasible by consumers who prefer to purchase live poultry. Previous scholarship has suggested this preference is due to cultural values of freshness. In this study, we present results from detailed interviews with shoppers in south China, including those who prefer live poultry and those who prefer pre-slaughtered poultry. We argue that broader concerns about food safety and quality, rather than freshness alone, drive the demand for LPMs. Live poultry provide sensory information that enable shoppers to evaluate safety and quality in ways that are not possible with pre-slaughtered, refrigerated meat. Based on these findings, we suggest that hygienic interventions into LPMs should recognize that not only freshness, but also trust, must be constructed and maintained in any intervention.

Quantifying Enteropathogen Contamination along Chicken Value Chains in Maputo, Mozambique: A Multidisciplinary and Mixed-Methods Approach to Identifying High Exposure Settings

BACKGROUND

Small-scale poultry production is widespread and increasing in low- and middle-income countries (LMICs). Exposure to enteropathogens in poultry feces increases the hazard of human infection and related sequela, and the burden of disease due to enteric infection in children < 5 y in particular is substantial. Yet, the containment and management of poultry-associated fecal waste in informal settings in LMICs is largely unregulated.

OBJECTIVES

To improve the understanding of potential exposures to enteropathogens carried by chickens, we used mixed methods to map and quantify microbial hazards along production value chains among broiler, layer, and indigenous chickens in Maputo, Mozambique.

METHODS

To map and describe the value chains, we conducted 77 interviews with key informants working in locations where chickens and related products are sold, raised, and butchered. To quantify microbial hazards, we collected chicken carcasses (n = 75 ) and fecal samples (n = 136 ) from chickens along the value chain and assayed them by qPCR for the chicken-associated bacterial enteropathogens C. jejuni/coli and Salmonella spp.

RESULTS

We identified critical hazard points along the chicken value chains and identified management and food hygiene practices that contribute to potential exposures to chicken-sourced enteropathogens. We detected C. jejuni/coli in 84 (76%) of fecal samples and 52 (84%) of carcass rinses and Salmonella spp. in 13 (11%) of fecal samples and 16 (21%) of carcass rinses. Prevalence and level of contamination increased as chickens progressed along the value chain, from no contamination of broiler chicken feces at the start of the value chain to 100% contamination of carcasses with C. jejuni/coli at informal markets. Few hazard mitigation strategies were found in the informal sector.

DISCUSSION

High prevalence and concentration of C. jejuni/coli and Salmonella spp. contamination along chicken value chains suggests a high potential for exposure to these enteropathogens associated with chicken production and marketing processes in the informal sector in our study setting. We identified critical control points, such as the carcass rinse step and storage of raw chicken meat, that could be intervened in to mitigate risk, but regulation and enforcement pose challenges. This mixed-methods approach can also provide a model to understand animal value chains, sanitary risks, and associated exposures in other settings. https://doi.org/10.1289/EHP11761.

Effect of biosecurity-based interventions on broiler crude mortality rate at an early stage of production in the small-scale farming system in Bangladesh

BACKGROUND

Biosecurity-based interventions are important health strategies for the control of infectious disease and improve productivity in broiler. There are various reasons why broilers die at the early stages of production; however, biosecurity measures are crucial in reducing the risk of disease prevalence and can therefore affect the overall deaths in a flock for a specific period (crude mortality rate [CMR]).

OBJECTIVES

This study was designed to determine the current biosecurity situation on small-scale broiler farms in Bangladesh and its relationship to the CMR during the early stages of production.

METHODS

A cross-sectional observational study was conducted on small-scale broiler farms (N = 57) located in peri-urban areas of Chattogram and Pabna districts of Bangladesh. Descriptive and predictive statistical analyses were performed to estimate the frequency of categorical variables and their effect on CMR.

RESULTS

The findings indicated that around 80% of small-scale broiler farms lacked adequate biosecurity measures. Both on day 1 (p = 0.012) and on days 2-14 (p = 0.003), flocks with inadequate biosecurity had considerably higher median CMRs. Farms that were near the neighbourhood used wood shavings as bedding, offered tube well/shallow well or supply line water, maintained a brief empty period (≤5 days) before introducing new flocks and began using antibiotics on day 1 all had significantly higher CMR at both days 1 and 2-14.

CONCLUSIONS

The findings point to the necessity of implementing stringent biosecurity measures in broiler production in locations where there is a shortage, which can lower the burden of arbitrary antibiotic usage and will lower total production costs due to crude mortality and management-related issues.

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.

The Impact of Experiences and Perceptions of Highly Pathogenic Avian Influenza (HPAI) on Water-Related Biosecurity Behaviour in Rural Vietnam

BACKGROUND

In Southeast Asia from 2004 to 2006, highly pathogenic avian influenza (HPAI) resulted in culling 45 million birds and jeopardizing sustainable agricultural production. HPAI is highly virulent; small-scale farms present a high-risk environment for disease transmission between animals and humans. We investigated how attitudes toward HPAI influence water-related biosecurity mitigation behaviors on small-scale farms in Vietnam using the conceptual framework Social Cognitive Theory.

METHOD

We analyzed a secondary cross-sectional data set from northern (Thai Binh) and southern (An Giang) provinces in Vietnam, describing a stratified randomized selection of 600 small-scale farmers who were interviewed using questionnaires and in-person interviews. Logistic regression analysis and odds ratios were used to examine relationships between factors influencing HPAI attitudes, social norms, perceived importance, and behaviors (α = 0.10) RESULTS: Concern about the severity of HPAI was significantly associated with increased perceived importance for all water management biosecurity methods (p < 0.01). Media and/or peer influence had negative effects on perceived importance to practice water-related biosecurity (p < 0.10). High importance of practice water-related biosecurity resulted in high uptake (p < 0.05). Past experiences with HPAI were significant in predicting perceived importance; none were significant in describing behavior uptake.

DISCUSSION

Biosecurity guidelines may not be consistent with management styles of Vietnamese small-scale farms; perceived importance of a behavior may be an important mediating variable. Gaps exist in uptake of water management practices as biosecurity for HPAI, potentially negatively affected by peer and media influence. Our results should be of interest to public health and policy authorities addressing HPAI mitigation.

Molecular epidemiology and pathogenicity of H5N1 and H9N2 avian influenza viruses in clinically affected chickens on farms in Bangladesh

Avian influenza virus (AIV) subtypes H5N1 and H9N2 co-circulate in poultry in Bangladesh, causing significant bird morbidity and mortality. Despite their importance to the poultry value chain, the role of farms in spreading and maintaining AIV infections remains poorly understood in most disease-endemic settings. To address this crucial gap in our knowledge, we conducted a cross-sectional study between 2017 and 2019 in the Chattogram Division of Bangladesh in clinically affected and dead chickens in farms with suspected AIV infection. Viral prevalence of each subtype was approximately 10% among farms for which veterinary advice was sought, indicating a high level of virus circulation in chicken farms despite the low number of reported outbreaks. The level of co-circulation of both subtypes on farms was high, with our study suggesting that in the field, the co-circulation of H5N1 and H9N2 can modulate disease severity, which could facilitate an underestimated level of AIV transmission in the poultry value chain. Finally, using newly generated whole-genome sequences, we investigate the evolutionary history of a small subset of H5N1 and H9N2 viruses. Our analyses revealed that for both subtypes, the sampled viruses were genetically most closely related to other viruses isolated in Bangladesh and represented multiple independent incursions. However, due to lack of longitudinal surveillance in this region, it is difficult to ascertain whether these viruses emerged from endemic strains circulating in Bangladesh or from neighbouring countries. We also show that amino acids at putative antigenic residues underwent a distinct replacement during 2012 which coincides with the use of H5N1 vaccines.

Avian influenza transmission risk along live poultry trading networks in Bangladesh

Live animal markets are known hotspots of zoonotic disease emergence. To mitigate those risks, we need to understand how networks shaped by trading practices influence disease spread. Yet, those practices are rarely recorded in high-risk settings. Through a large cross-sectional study, we assessed the potential impact of live poultry trading networks’ structures on avian influenza transmission dynamics in Bangladesh. Networks promoted mixing between chickens sourced from different farming systems and geographical locations, fostering co-circulation of viral strains of diverse origins in markets. Viral transmission models suggested that the observed rise in viral prevalence from farms to markets was unlikely explained by intra-market transmission alone, but substantially influenced by transmission occurring in upstream network nodes. Disease control interventions should therefore alter the entire network structures. However, as networks differed between chicken types and city supplied, standardised interventions are unlikely to be effective, and should be tailored to local structural characteristics.

Association between farm biosecurity practices and antimicrobial usage on commercial chicken farms in Chattogram, Bangladesh

Commercial broiler and layer farming represents an important livestock industry in Bangladesh. Adequate biosecurity practices are considered to be an effective method to prevent infectious disease occurrence on commercial poultry farms, but antimicrobials are also frequently administered to reduce disease risk. We conducted a cross-sectional study on 57 commercial layer and 83 broiler farms in eight subdistricts of the Chattogram district in Bangladesh to investigate the relationship between implemented biosecurity practices and the use of antimicrobials on these farms. We used a causal diagram framework to inform multi-level mixed effects logistic regression models to explore the total and direct effects of biosecurity practices implemented on commercial farms on prophylactic versus therapeutic antimicrobial usage on these farms. Overall, inadequate biosecurity was more common on broiler compared to layer farms and on farms rearing smaller flock sizes. For example, separation of sick from healthy birds was more common on layer farms (85.2 %, 46/54) compared to broiler farms (38.6 %, 32/83) (p = 0.001). Prophylactic administration (compared to therapeutic use) of antimicrobials was less common on farms that were separating sick birds from the healthy birds (total and direct effect OR = 0.1, 95 % CI: 0.1-0.6, p = 0.006) and less common on farms that used a poorer quality source of water for drinking, cooling, cleaning, and washing (total and direct effect OR = 0.3, 95 % CI: 0.1-0.9, p = 0.036). In contrast, farmers that used washing facilities (versus non-usage of washing facilities) were more likely to administer antimicrobials prophylactically (total and direct effect OR = 3.9, 95 % CI: 1.3-11.3, p = 0.012). The null model ICC indicated significant clustering at the subdistrict level (ICC = 0.20, 95 % CI: 0.04-0.60, p = 0.013), but the ICC was reduced after including flock size and farm type, and the biosecurity practices as fixed effects (ICC = 0.14, 95 % CI: 0.02-0.59, p = 0.0661). Overall, our study highlighted that a large proportion of commercial chicken farmers mediated poor biosecurity practices by prophylactic application of antimicrobials. The results of our research can be used to inform awareness programs for commercial poultry farmers emphasizing the importance of improving biosecurity rather than using antimicrobials to reduce the risk of poultry disease occurrence.

Avian Influenza Risk Environment: Live Bird Commodity Chains in Chattogram, Bangladesh

In this paper, we identify behaviours in live bird commodity chains in Chattogram, Bangladesh, which may influence the risk of pathogen emergence and transmission: the nature of poultry trade, value appropriation and selling sick or infected birds. Examining the reasons why actors engage in these behaviours, we emphasise the politics of constraints within a context of real-world decisions, governed by existential and pragmatic agency. Focusing on contact zones and entanglement, analysing patron-client relationships and precarious circumstances, we argue that agency and structure specific to the Bangladeshi context produce a risk environment. Structural constraints may reinforce risky occupational practises and limit individual agency. Structural constraints need to be addressed in order to tackle animal and zoonotic disease risk along live animal commodity chains.

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.

Risk Areas for Influenza A(H5) Environmental Contamination in Live Bird Markets, Dhaka, Bangladesh

We evaluated the presence of influenza A(H5) virus environmental contamination in live bird markets (LBMs) in Dhaka, Bangladesh. By using Bernoulli generalized linear models and multinomial logistic regression models, we quantified LBM-level factors associated with market work zone–specific influenza A(H5) virus contamination patterns. Results showed higher environmental contamination in LBMs that have wholesale and retail operations compared with retail-only markets (relative risk 0.69, 95% 0.51–0.93; p = 0.012) and in March compared with January (relative risk 2.07, 95% CI 1.44–2.96; p<0.001). Influenza A(H5) environmental contamination remains a public health problem in most LBMs in Dhaka, which underscores the need to implement enhanced biosecurity interventions in LBMs in Bangladesh.

Factors influencing chicken farmers' decisions to implement prevention and control measures to reduce avian influenza virus spread under endemic conditions

The ongoing circulation of Highly Pathogenic Avian Influenza (HPAI) H5N1 poses a threat to both poultry and public health. Adapting the constructs of the Health Belief Model (HBM) framework, we investigated perceptions of backyard, commercial broiler and layer chicken farmers to implement HPAI prevention and control measures in Bangladesh. Two cross-sectional studies were conducted in 2016 and 2017 on 144 backyard, 106 broiler and 113 layer chicken farms. Using Structural Equation Modelling, we modelled the direct and indirect effects on farmers' perceptions on taking HPAI prevention and control actions. Our results indicate that farmers of different chicken production systems have different decision-making processes. While perceived barriers to the implementation of prevention and control measures (e.g. wearing protective equipment when handling chickens) prevented both broiler and backyard farmers to adopt interventions, perceived benefits of measures (e.g. maintaining high biosecurity will reduce the risk of birds becoming sick) strongly influenced commercial farmers' decisions, but not backyard farmers' decisions. Information provided on HPAI through media, meetings or via information campaigns played an important role in farmers' decision-making in all production systems. Outcomes of this research can be used to tailor advice on HPAI control and prevention to different poultry farming groups by accounting for specific factors influencing their decision-making, instead of using one-size-fit-all communication approach.

Meat Safety in Northern Tanzania: Inspectors' and Slaughter Workers' Risk Perceptions and Management

Through a social scientific lens, this paper considers the risk perceptions and "risk-based decision-making" of two key groups in a northern Tanzanian context: (1) frontline government meat inspectors and health officers charged with ensuring that red meat sold commercially is safe for people to consume, and (2) the workers who slaughter and process cattle and red meat prior to its sale in rural butcheries. In contrast to techno-scientific understandings of disease risk and "rational" approaches to its management, this paper foregrounds the role of social, economic and institutional context in shaping the perceptions and practices around meat safety of these actors whose daily, close proximity to meat means they play a significant role in mitigating potential meat-borne disease. We show how limited resources, and a combination of scientific and local knowledge and norms result in "situated expertise" and particular forms of risk perception and practice which both enhance and compromise meat safety in different ways. Actors' shared concerns with what is visible, ensures that visibly unsafe or abnormal meat is excluded from sale, and that infrastructure and meat is kept "clean" and free of certain visible contaminants such as soil or, on occasion, feces. While such contaminants serve as a good proxy for pathogen presence, meat inspectors and especially slaughter workers were much less aware of or concerned with invisible pathogens that may compromise meat safety. The role of process and meat handling did not figure very strongly in their concerns. Microorganisms such as Salmonella and Campylobacter, which can easily be transferred onto meat and persist in slaughter and meat sale environments, went unacknowledged. Although health officers expressed more concern with hygiene and meat handling, their influence over slaughter process and butchery operations was unclear. Ultimately, recognizing the perceptions and practices of frontline actors who engage with meat, and the ways in which social, material and institutional realities shape these, is important for understanding how decisions about risk and meat safety are made in the complexity and context of everyday life, and thus for finding effective ways to support them to further enhance their work.

Meat Safety in Tanzania's Value Chain: Experiences, Explanations and Expectations in Butcheries and Eateries

Urbanisation is associated with changes in consumption patterns and food production processes. These patterns and processes can increase or decrease the risks of outbreaks of foodborne diseases and are generally accompanied by changes in food safety policies and regulations about food handling. This affects consumers, as well as people economically engaged in the food value chain. This study looks at Tanzania's red meat value chain-which in its totality involves about one third of the population-and focuses on the knowledge, attitudes and reported practices of operators of butcheries and eateries with regards to meat safety in an urban and in a rural environment. We interviewed 64 operators about their experiences with foodborne diseases and their explanations and expectations around meat safety, with a particular emphasis on how they understood their own actions regarding food safety risks vis-à-vis regulations. We found operators of eateries emphasising their own agency in keeping meat safe, whereas operators of butcheries-whose products are more closely inspected-relied more on official inspections. Looking towards meat safety in the future, interviewees in rural areas were, relative to their urban counterparts, more optimistic, which we attribute to rural operators' shorter and relatively unmediated value chains.