Effects of seasonal meteorological variables on E. coli persistence in livestock faeces and implications for environmental and human health

Abstract

Agriculture contributes significant volumes of livestock faeces to land. Understanding how faecal microbes respond to shifts in meteorological patterns of contrasting seasons is important in order to gauge how environmental (and human health) risks may alter under a changing climate. The aim of this study was to: (i) quantify the temporal pattern ofE. coligrowth within dairy faeces post defecation; and (ii) deriveE. coliseasonal population change profiles associated with contrasting environmental drivers. Evaluation of the die-off dynamics ofE. colirevealed that a treatment mimicking drought and warming conditions significantly enhanced persistence relative toE. coliin faeces that were exposed to field conditions, and that this pattern was consistent across consecutive years. The internal temperature of faeces was important in driving the rate of change in theE. colipopulation in the immediate period post defecation, with mostE. coliactivity (as either die-off or growth) occurring at low dry matter content. This study highlighted that the use of seasonalE. colipersistence profiles should be approached with caution when modelling environmental and human health risks given the increased likelihood of atypical seasonal meteorological variables impacting onE. coligrowth and die-off.