Investigation of avian influenza outbreak in birds at the Akatsi South Municipality, Ghana, 2025

Abstract

Introduction: Avian influenza (AI) is a contagious viral disease of birds. Highly pathogenic AI (HPAI) causes high poultry mortality, major economic losses, and poses a zoonotic risk. On 26 May 2025, sudden poultry deaths were reported on a farm in Akatsi, prompting an investigation to determine the magnitude, source, transmission mode, and control measures. Methods: We investigated the AI outbreak in the Akatsi-South Municipality, Volta Region, Ghana, from June 30 to July 4, 2025. We defined a case as a sudden death of birds, discolouration of wattle or comb, coughing, or diarrhoea from 4th May. In-depth interviews were conducted with farm managers and workers using a standardised AI outbreak investigation checklist. Farms were assessed for biosecurity, human exposures, and environmental risk factors. Descriptive analysis was used to characterise the outbreak in terms of time and place. Attack rates (AR) were calculated to measure the magnitude. Data were summarised using frequencies and proportions and presented with tables, charts, and a spot map. Results: The index farm recorded its first mortality on 22nd May 2025, with subsequent spread to 11 others, affecting 80% (12/15) of farms. Farm-specific AR ranged from 1.6% to 66.7%, with an overall rate of 20.3%. Biosecurity was inadequate, and environmental assessments revealed the presence of migratory birds and rodents on the farms. Laboratory investigation confirmed HPAI H5N1. On average, depopulation took 12 days (range: 8–16). Likely transmission routes included shared feed mills and farm workers, and maize sourced from Togo, where outbreaks had been ongoing since February 2025. No human infections were reported. Conclusion: Poor biosecurity and cross-border feed sourcing facilitated farm-to-farm transmission. Depopulation and disinfection were the interventions implemented to contain the outbreak. Biosecurity measures, such as enforcing exit and entry protocols, were also strengthened on unaffected farms.