Can environmental DNA be used for aquatic biosecurity in the aquarium fish trade?

Trujillo-González, A., Becker, J.A., Huerlimann, R., Saunders, R.J., and Hutson, K.S. (2020) Can environmental DNA be used for aquatic biosecurity in the aquarium fish trade? Biological Invasions, 22. pp. 1011-1025.

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Abstract

The global ornamental fish trade enables translocation of exotic aquatic pathogens. In many countries, health certification and visual inspection of imported fish are key components of biosecurity to prevent the introduction of aquatic diseases. However, infected fish do not always exhibit clinical or behavioural signs of disease, and alternatives to visual inspection must be validated. This study examined the use of environmental DNA (eDNA) to detect sub-clinical parasite infections at border control. We simulated the export process of live ornamental fish in which non-infected fish, infected fish, treated fish, and non-infected fish held in contaminated water were packaged and delivered in 48 h. Quantitative PCR (qPCR) was used to detect eDNA of an ectoparasitic monogenean, Neobenedenia girellae, infecting barramundi, Lates calcarifer. The qPCR assay did not reliably detect parasite eDNA under 2 copies/mu L from fish with sub-clinical infections (mean parasite intensity = 6.80 +/- 4.78 S.D.), suggesting parasite infection loads tested in this study may be too low for reliable detection within the timeframe used to export live ornamental fish. Quantitative PCR tests detected parasite eDNA in 50% of infected fish and 70% of non-infected fish in contaminated transport water. This indicated a high plausibility of false negative detections because of low eDNA concentrations in transport water and false positive detections of DNA from dead parasites in the water. Environmental DNA screening methods for border control biosecurity must overcome limitations posed by low eDNA concentrations in the water, limited timeframes for sample processing, and the essential differentiation between live parasite infections and dead, non-viable parasites.

Item ID: 61232
Item Type: Article (Research - C1)
ISSN: 1573-1464
Keywords: Parasites, eDNA, Ornamental fish, Quarantine, Border control, Transboundary animal disease
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Copyright Information: © Springer Nature Switzerland AG 2019.
Additional Information:

A version of this publication was included as Chapter 6 of the following PhD thesis: Trujillo-González, Alejandro (2018) Parasite threats from the ornamental fish trade. PhD thesis, James Cook University, which is available Open Access in ResearchOnline@JCU. Please see the Related URLs for access.

Funders: Fisheries Research and Development Corporation (FRDC), James Cook University, University of Sydney
Projects and Grants: FRDC Project no. 2014/001
Research Data: http://doi.org/10.25903/5bd295b16d2ad
Date Deposited: 18 Dec 2019 07:41
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050103 Invasive Species Ecology @ 50%
06 BIOLOGICAL SCIENCES > 0604 Genetics > 060499 Genetics not elsewhere classified @ 50%
SEO Codes: 96 ENVIRONMENT > 9604 Control of Pests, Diseases and Exotic Species > 960401 Border Biosecurity (incl. Quarantine and Inspection) @ 100%
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