WISCONSIN & UPPER MICHIGAN Survey of Mississippi River Unionids for Viruses Associated with a Mortality Event in the Clinch River

Overview

Many mussel populations in North America and other parts of the world have seen catastrophic declines and mass mortality events, raising concerns about what this trend may mean for aquatic environments. Mussels provide invaluable services to the ecosystem, from water filtration to water quality indication to food web enhancement. Their shells provide habitats and nesting sites for small fish and insects. In the past, unionid population declines have been attributed to pollution, habitat degradation and the introduction of exotic species with little consideration given to the role of disease until recently. The cause of these declines remains enigmatic, however a link was discovered between cases of mortality and a novel densovirus (hereafter referred to as Clinch densovirus 1). The purpose of this study was to determine the prevalence of this densovirus and several other viruses (Clinch CRESS virus 1, Clinch picorna-like virus 1) among mussels in the Mississippi river. Samples from 59 mussels of various species and location were collected, and hemolymph samples were taken from their anterior adductor muscles. A subset of 30 samples was chosen for analysis. Samples were analyzed via recently developed qPCR assays, and results indicated that two Pocketbooks (Lampsilis cardium) tested positive for Clinch picorna-like virus 1. One Wabash pigtoe (Fusconaia flava) was positive for both Clinch picorna-like virus 1 and Clinch densovirus 1. Further study is necessary to confirm they are indeed the same viruses, but results may indicate a range and host expansion for the viruses, which could have implications for mussel populations in the Mississippi river. The assays evaluated in this study could be used to survey different geographic regions, to evaluate mortality events, and to study how much the virus replicates in experimental studies.

Competition history

• JSHS 2022 Category not listed

Resources

• National JSHS abstract book ↗

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