Parasite DNA detection in water samples enhances crayfish plague monitoring in asymptomatic invasive populations

Sieber, Natalie; Hartikainen, Hanna; Krieg, Raphael; Zenker, Armin; Vorburger, Christoph

Abstract

Invasive species can facilitate the spread of pathogens by first providing asymptomatic host reservoirs, and then driving disease outbreaks in native populations through pathogen spillover. An example of this are invasive crayfish species in Europe (Faxonius limosus, Pacifastacus leniusculus, Procambarus clarkii), which carry the deadly plague agent (Aphanomyces astaci). Effective disease management requires comprehensive monitoring, however, pathogen detection in carrier populations with low pathogen prevalence and intensities is challenging. We simultaneously collected and analysed crayfish tissue samples of invasive crayfish populations and water samples to compare A. astaci detection in different sample types using quantitative PCR. Combined, the two sampling methods revealed A. astaci presence with DNA concentrations above limit of detection (LOD; the lowest concentration which can be detected with reasonable certainty) in 13 of 23 invasive crayfish populations. In four additional sites, A. astaci DNA concentrations below LOD were found in water. In four populations only were A. astaci concentrations above LOD detected in both sample types and in three populations in concentrations above LOD in tissue but below LOD in water. The likely reason for these discrepancies is the low A. astaci prevalence and concentration in resistant invasive crayfish, which limit detection reliability. Consistency may be improved by timing surveys with seasonal periods of high A. astaci abundance and by increasing water sampling effort. Considering the ease of collecting eDNA samples, compared to crayfish tissue sampling, eDNA methods would facilitate frequent and comprehensive surveys. However, remaining uncertainties in eDNA-based detection reveal the relevance of combining monitoring tools to improve detection of invasive pathogens and their management.

• Journal Article Type: Article
• Acceptance Date: Oct 6, 2021
• Online Publication Date: Nov 1, 2021
• Publication Date: Jan 1, 2022
• Deposit Date: Aug 3, 2022
• Publicly Available Date: Aug 5, 2022
• Journal: Biological Invasions
• Print ISSN: 1387-3547
• Electronic ISSN: 1573-1464
• Publisher: Springer Science and Business Media LLC
• Peer Reviewed: Peer Reviewed
• Volume: 24
• Issue: 1
• Pages: 281-297
• DOI: https://doi.org/10.1007/s10530-021-02644-y
• Keywords: Ecology; Ecology, Evolution, Behavior and Systematics
• Public URL: https://nottingham-repository.worktribe.com/output/7357708
• Publisher URL: https://link.springer.com/article/10.1007/s10530-021-02644-y
• Additional Information: Received: 31 August 2020; Accepted: 6 October 2021; First Online: 1 November 2021; : ; : The authors declare that they have no conflict of interest.; : All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.