Exploring whether native pathogens can be used to control AIS

Project manager: Nicholas Phelps

Phase 1 Description:

Overall Project Outcome and Results

Although ambitious, eradication of aquatic invasive species is an ultimate goal of MAISRC. One possible method would be through the introduction or promotion of species-specific pathogens. This high-risk, high-reward approach must be carefully assessed with thorough investigation and scientifically justified risk assessment. As a first step in Phase I of a multi-phase project, invasive carp species were surveyed to identify viruses circulating in these populations. Nearly 700 common carp were collected from Minnesota lakes, 120 silver carp from the Fox and Illinois Rivers, and a variety of carp species from eight mortality events.  All fish were negative for cyprinid herpes viruses 1, 2, and 3, carp edema virus, and spring viremia of carp virus.  However, advanced molecular approaches and virus isolation detected several known and unknown viruses of significance. This included novel viruses from at least seven RNA virus families: picornavirus, reovirus, hepatovirus, astrovirus, hepatitis virus, betanodavirus, and paramyxovirus. The novel carp paramyxovirus was associated with a mortality event and shows particular promise for further evaluation as a biocontrol agent.  The standard operating procedures developed during Phase I will be essential to advance future work on this and related pathogen discovery research.  Unfortunately, Phase I was met with several unforeseen challenges that hindered completion of all proposed activities, including laboratory renovation progress, service provider availability and delays, and access to mortality events.  In spite of these setbacks, this project has significantly advanced our understanding of invasive carp viruses and positioned us well to for future research efforts.  Phase I of this project provided researchers and managers with baseline data on viruses circulating in invasive carp populations in the region.  These data have been broadly disseminated at scientific conferences, peer-reviewed and lay publications, and through MAISRC communications.  Continued efforts to build upon this line of research will commence in Phase II of this long-term effort.

Project Results Use and Dissemination

The data generated from this study was presented five times in different scientific and stakeholder conferences. The research data from this study will generate three or more publications, which are currently in preparation. These are tentatively titled (i) Prevalence of RNA viruses in invasive carp populations in Minnesota; (ii) Genomic-based characterization of novel RNA viruses present in invasive carp population in Minnesota; (iii) Molecular characterization of novel RNA viruses associated with fish mortality events in different lakes in Minnesota; (iv) Next generation sequencing as a tool for diagnosis and discovery of novel pathogens.

Project start date: 2013

Estimated project end date: 2016

Progress and updates:

Phase 2: Virus discovery and evaluation for use as potential biocontrol agents

Description: Phase I of this project provided initial baseline data on viruses of carp species in the region. Phase II will build upon this work for carp species and now include zebra mussels to utilize newly developed techniques to more strategically identify viral biocontrol candidates for control of invasive carp and zebra mussels. More specifically, Phase II will:

  • Collect apparently healthy invasive carp and mussel species in the Midwest region;
  • Collect samples from mortality events of native and invasive fish and mussel populations in the Midwest region;
  • Conduct virus discovery by next generation sequencing and culture potential pathogens;
  • Determine the disease causing potential of two selected viruses, one for native and invasive fish and the other for native and invasive mussels; and
  • Communicate findings to scientific, management, and public stakeholders.

This will provide the scientific foundation to begin to evaluate specific pathogens for invasive species control. Furthermore, understanding the virome of invasive species will serve as a potential early indicator for the movement and distribution of pathogens that may threaten native species. Phase II will largely be basic research generating baseline data on the virome diversity of invasive and native species. Significant effort will also be in applied research whereby diagnostic and disease challenge findings will be used to inform the health management of fish populations.