A review of the abundance, behaviour and detection of clostridial pathogens in agricultural soils. (15th July 2019)

• Record Type: Journal Article
• Authors: Palmer, Joseph S.; Hough, Rupert L.; West, Helen M.; Avery, Lisa M.
• Is Part Of: European journal of soil science. Volume 70:Number 4(2019)
• Page Start: 911
• Page End: 929
• Publication Date: 2019-07-15
• Subjects: anaerobes -- bacterial survival -- Clostridium -- livestock disease -- soil‐borne pathogens; Soil science -- Periodicals; 631.4
• DOI: 10.1111/ejss.12847
• Languages: English
• ISSNs: 1351-0754

Abstract

Abstract: The soil is a reservoir for various clostridial pathogens, with agricultural soils representing a major source of contamination for overlying crops and grazing livestock. Understanding the prevalence and behaviour of pathogens in these soils is fundamental to ascertaining and mitigating the risk of disease from agroecosystems. This article reviews research pertaining to the overall distribution and abundance of clostridial pathogens in the soil while identifying possible environmental and soil factors influencing their behaviour. Large‐scale soil screens have identified pathogens across the globe, although some Clostridium botulinum toxinotypes are more prevalent in certain geographic regions. Faecal inputs and organic waste amendments to the soil can elevate the levels of enteric clostridial pathogens in the soil and the subsequent disease risk, as highlighted by case–control studies. The ability of Clostridia to sporulate results in their long‐term persistence post‐introduction, increasing the time period for disease transmission. Regularly or permanently saturated soils may also enhance survival, or potentially facilitate the regrowth of some indigenous or introduced Clostridia. This is supported by the high prevalence of Clostridia in paddy soils, greater detection of pathogens in flooded soils, and the higher onset of some clostridial diseases in regions with poorly drained soils. Future research should elucidate soil types and environmental conditions which can enhance pathogen survival/regrowth. The adoption of molecular and sequencing technologies for future diagnostics can facilitate more sensitive detection and a higher resolution of pathogen typing, allowing a better understanding of pathogen population dynamics in farm soils and disease epidemiology. Highlights: Understanding the behaviour of soil‐borne clostridial pathogens is key for disease management. Soil, environmental and management factors affecting pathogen survival/introduction are discussed. Soil waterlogging and application of organic soil amendments may increase the number of soil pathogens. More pathogen surveillance and standardisation of diagnostics to better understand behaviour is needed.