Mass mortality events of common carp (Cyprinus carpio, carp) associated with carp edema virus (CEV) alone or in coinfections with koi herpesvirus (KHV), is an emerging issue. Despite recent outbreaks of CEV in wild carp populations, the host range of North American species has not been well studied. To that end, we intensively sampled carp (n = 106) and co-habiting native fish species (n = 5 species; n = 156 total fish) from a CEV-suspect mass-mortality event of carp in a small Minnesota lake (Lake Swartout). Additionally, fecal and regurgitant samples (n = 73 each) from double-crested cormorants (Phalacrocorax auritus, DCCO) were sampled to test the potential of DCCO to act as a vector for virus transmission. CEV was confirmed to be widespread in the Lake Swartout carp population during the outbreak with high viral loads and histological confirmation, suggesting that CEV was the cause of the mortality event. There were no detections of CEV in any native fish species; however, DCCO regurgitant and fecal samples were positive for CEV DNA. In addition, three CEV-positive and one CEV + KHV-positive mortality events were confirmed with no observed mortality or morbidity of non-carp species in other lakes. This study provides evidence that CEV infection and disease may be specific to carp during mortality events with mixed-species populations, identifies DCCO as a potential vector for CEV, and further expands the known range of CEV, as well as coinfections with KHV, in North America.
Bibliographical noteFunding Information:
This research was funded by the Environment and Natural Resource Trust Fund, as recommended by the Minnesota Aquatic Invasive Species Research Center, and state of Minnesota. Field support was provided by Sophie Halvorson and Morgan Linn. Lake access was kindly provided by Alan Wolff. We also thank Alex Primus for assistance with histological review. Carp from three mortality events in Minnesota lakes (Traverse, Crystal, and Currant) were collected by Minnesota Department of Natural Resources (MNDNR) while carp from Pymatuning Reservoir were collected by the Pennsylvania Fish and Boat Commission. DCCO samples were collected in collaboration with the USDA National Wildlife Disease Program and the MNDNR.
Funding: This research was funded by the Environment and Natural Resource Trust Fund, as recommended by the Minnesota Aquatic Invasive Species Research Center, and state of Minnesota.
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- carp edema virus
- emerging wildlife disease
- host range
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't