Effect of carcase decomposition on the inactivation of foot-and-mouth disease virus under northern Australian conditions

Abstract

Objective: The control of foot-and-mouth disease virus (FMDV) across northern Australia would likely result in animal carcases that will often be inaccessible for disposal. The aim of this preliminary study was to determine whether the natural pH and/or temperature changes that occur within the skeletal muscle and/or body cavities of a decomposing carcase shot and left in situ in this environment would be sufficient to inactivate FMDV. Methods: Study pigs (n = 30), cattle (6), sheep (6) and goats (8) were shot in one of four locations in Queensland. Carcase temperature and pH and ambient temperature were measured every 15–60 min for up to 46 h in two sites per animal: central (thoracic/abdominal cavity) and peripheral (skeletal muscle) or brain. A target pH ≤ 6.0 at any time and/or a target temperature ≥ 43°C for ≥ 7 h or ≥ 49°C for ≥ 1 h were used as proxies for achievement of FMDV inactivation. Results: The target temperature was achieved in only one goat carcase. However, within 16 h of death, the target central and/or peripheral pH was attained in 88–100% of pig, cattle and sheep carcases. Increasing hours since death and death in the late morning/afternoon, relative to the early morning, were positively associated with attaining the target central carcase pH. Conclusion: This preliminary study provided evidence that FMDV inactivation may be achieved in the skeletal muscle and/or body cavities of carcases left under northern Australian conditions, though further work on pH changes in bone marrow are required. © 2018 Australian Veterinary Association