Biosecurity audit and tailored grassland and facility biosecurity measures to reduce the occurrence of Rhodococcal infection in breeding centres

International audienceBackground: Rhodococcus equi (R.equi) VapA+ is a facultative pathogen that could induce pneumonia in foals below 6 months of age. Rhodococcal infection may be severe and is a recognised threat to the equine breeding industry. Infected foals may require antibio-therapy for several weeks with associated issues such as side effects and/or bacterial resistance. To date, no vaccine is commercially available, and protection induced by hyperimmune plasma has limitations.Objectives: To validate a tailored biosecurity approach to reduce disease occurrence in equine breeding centres/farms.Study design: Proof of concept; field biosecurity audit, design/implementation of tailored biosecurity measures and longitudinal annual monitoring (up to 3 years).Methods: 5 breeding centres (from 50 to 200 breeding mares) with a disease history ranging from no cases to almost 80% per year were selected. A biosecurity audit was conducted in each centre to determine existing measures. A tailored biosecurity programme (including grassland and facilities management, animal/human/vehicle flows etc.) was subsequently designed with owners and veterinarians to support/strengthen existing measures. Soil samples were semi-quantitatively analysed to identify areas with high concentration of R. equi VapA+.Results: Bacterial analyses were successfully used to map “at risk” areas and to adapt foals’ paddock allocation, animal movement flows and grassland management accordingly. The combination of measures such as regular disinfection protocols, faeces removal, annual reseeding, liming, watering and use of heavy sand, reduced disease occurrence in all previously affected centres when implemented (e.g. from 49 suspicious/confirmed cases prior to audit to 2 cases per year for 2 years). Audit and annual monitoring also increased general awareness about other equine infectious diseases.Main limitations: The audit was standardised but implemented measures were centre-specific. Confirmation of results will require a larger number of centres and standardisation.Conclusions: Tailored grassland and facility management could help to reduce the occurrence of Rhodococcal infection in the field