Sea star-associated densovirus (SSaDV) belongs to the Parvoviridaefamily. Like the other members of its family, it is a single-stranded DNA virus. SSaDV has been suggested to be an etiological agent of sea star wasting disease, but conclusive evidence has not yet been obtained.[1] Further work in 2018 and 2020 re-examined the association between SSaDV and sea star wasting and found no evidence in both the original work and subsequent surveys of sea stars.[2][3] More recently, densoviruses associated with echinoderms were recognized as forming persistent infections in their hosts [4] and become endogenized within sea star genomic DNA.[3] Densoviruses including SSaDV become more pronounced during sea star wasting progression, but no single strain is associated with sea star wasting disease.[5]
Epidemiology
SSaDV occurs in sea stars from southern Alaska to Baja California. It tends to occur during large outbreaks of starfish-afflicting diseases with high mortality rates, as it has in 1972, 1978, 2013, and 2014. See Sea star wasting disease.[1] The virus was observed in wasting Pycnopodia helianthoides, and detected in small quantities in healthy sea stars and aquarium sediments.[1] The highest viral load was found in the body wall of the central disk.[1] A similar virus infecting sea stars on the Atlantic Coast of North America is found in only healthy specimens.[4] As of 2021, SSaDV is no longer believed to be associated with sea star wasting disease but may rather be one of many viruses that replicate as a consequence of disease process.[6]
Structure
The genomic characteristics of SSaDV are similar to the other members of the genus Ambidensovirus.[1] It is predicted to be a non-enveloped icosahedral particle at ~25 nm, although the virus has never been imaged.[1]
