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

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, antibiotic resistance, and genomic characterisation of Campylobacter spp. in retail chicken in Hanoi, Vietnam

Campylobacter spp. are a leading cause of bacterial foodborne zoonosis worldwide, with poultry meat and products recognised as a significant source of human infection. In Vietnam there are few data regarding the occurrence, antimicrobial resistance, and genomic diversity of Campylobacter in poultry and poultry meat. The aim of this study was to estimate the prevalence of Campylobacter in chicken meat at retail in Hanoi, determine antimicrobial sensitivities of the Campylobacter isolated, and assess their genetic diversity. A total of 120 chicken meat samples were collected from eight traditional retail markets (n=80) and four supermarkets (n=40). Campylobacter was isolated following ISO 10272-1 : 2017 and identification verified by PCR. The prevalence of Campylobacter was 38.3 % (46/120) and C. coli was the most prevalent species in both retail markets (74 %) and supermarkets (88 %). The minimum inhibitory concentrations for ciprofloxacin, erythromycin, gentamicin, nalidixic acid, streptomycin, and tetracycline were determined by broth microdilution for 32 isolates. All characterised Campylobacter were resistant to ciprofloxacin, nalidixic acid, and tetracycline, with corresponding resistance determinants detected in the sequenced genomes. Most C. coli were multidrug resistant (24/28) and two harboured the erythromycin resistance gene ermB on a multiple drug-resistance genomic island, a potential mechanism for dissemination of resistance. The 32 isolates belonged to clonal complexes associated with both poultry and people, such as CC828 for C. coli. These results contribute to the One Health approach for addressing Campylobacter in Vietnam by providing detailed new insights into a main source of human infection and can inform the design of future surveillance approaches.