The etiology of Sea Star Wasting Syndrome is hypothesized to be caused by a densovirus, SSaDV, that has previously been reported on the Pacific and Atlantic coasts of the United States. In this study, we reevaluated the presence of SSaDV among sea stars from the North American Atlantic Coast and in doing so discovered a novel densovirus we have named Asterias forbesi associated densovirus (AfaDV) that shares 78% nucleotide pairwise identity to SSaDV. In contrast to previous studies, SSaDV was not detected in sea stars from the North American Atlantic Coast. Using a variety of PCR-based techniques, we investigated the tissue tropism, host specificity, and prevalence of AfaDV among populations of sea stars at fiv... More
The etiology of Sea Star Wasting Syndrome is hypothesized to be caused by a densovirus, SSaDV, that has previously been reported on the Pacific and Atlantic coasts of the United States. In this study, we reevaluated the presence of SSaDV among sea stars from the North American Atlantic Coast and in doing so discovered a novel densovirus we have named Asterias forbesi associated densovirus (AfaDV) that shares 78% nucleotide pairwise identity to SSaDV. In contrast to previous studies, SSaDV was not detected in sea stars from the North American Atlantic Coast. Using a variety of PCR-based techniques, we investigated the tissue tropism, host specificity, and prevalence of AfaDV among populations of sea stars at five locations along the Atlantic Coast. AfaDV was detected in three sea star species (Asterias forbesi, Asterias rubens, and Henricia sp) found in this region and was highly prevalent (>80% of individuals tested, n=134), among sampled populations. AfaDV was detected in the body wall, gonads, and pyloric caeca (digestive gland) of specimens but was not detected in their coelomic fluid. A significant difference in viral load was found between tissue types with the pyloric caeca having the highest viral loads. Further investigation of Asterias forbesi gonad tissue found germline cells (oocytes) to be virus positive, suggesting a potential route of vertical transmission. Taken together, these observations show that the presence of AfaDV is not an indicator of Sea Star Wasting Syndrome because AfaDV is a common constituent of these animals' microbiome, regardless of health.Importance Sea Star Wasting Syndrome is a disease primarily observed on the Pacific and Atlantic coast of North America that has significantly impacted sea star populations. The etiology of this disease is unknown though hypothesized to be caused by a densovirus, SSaDV. However, previous studies have not found a correlation between SSaDV to Sea Star Wasting Syndrome on the North American Atlantic Coast. This study suggests that this observation may be explained by the presence of a genetically similar densovirus, AfaDV, that may have confounded previous studies. SSaDV was not present in sea stars screened in this study, and instead AfaDV was commonly found in sea star populations across the New England region with no apparent signs of disease. These results suggest that sea star densoviruses may be common constituents of the animal's microbiome, and the diversity and extent of these viruses among wild populations may be greater than previously recognized.,Copyright © 2020 Jackson et al.
