A Highly Prevalent and Pervasive Densovirus Discovered among Sea Stars from the North American Atlantic Coast

ABSTRACT The etiology of sea star wasting syndrome is hypothesized to be caused by a densovirus, sea star-associated 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 that we have named Asterias forbesi-associated densovirus (AfaDV), which shares 78% nucleotide pairwise identity with 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 (copies mg−1) was found between tissue types, with the pyloric caeca having the highest viral loads. Further investigation of Asterias forbesi gonad tissue found germ line 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 Coasts of North America that has significantly impacted sea star populations. The etiology of this disease is unknown, although it is hypothesized to be caused by a densovirus, SSaDV. However, previous studies have not found a correlation between SSaDV and 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 animals’ microbiome, and the diversity and extent of these viruses among wild populations may be greater than previously recognized.

A highly prevalent and pervasive densovirus discovered among sea stars from the North American Atlantic Coast

Viral metagenomes prepared from tissues from Forbes’ sea star (Asterias forbesi) led to the discovery of a complete genome of a novel sea star densovirus (AfaDV). The genome organization of AfaDV and phylogenetic analysis place this virus among the Ambidensovirus genus in the subfamily Densoviridae, family Parvoviridae. AfaDV shares 78% nucleotide pairwise identity to the sea star associated densovirus (SSaDV), previously described as the putative causative agent of Sea Star Wasting Syndrome among sea stars from the Northwest Pacific. SSaDV was not found in specimens collected in this study, and the discovery of AfaDV might explain previous reports of SSaDV among sea stars from the Atlantic Coast. A qPCR assay was designed to assess tissue tropism, host specificity, and prevalence of AfaDV among wild populations of sea stars at five locations on the North American Atlantic Coast. AfaDV was detected in all three common sea star species (Asterias forbesi, Asterias rubens, and Henricia sp.) found in the region and was highly prevalent (80-100% of individuals tested, n=134), among populations collected at disparate sites 7 years apart. 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 load suggesting it is the primary site of viral replication in the animal. 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 AfaDV is not an indicator of Sea Star Wasting Syndrome because AfaDV is a common constituent of these animals’ microbiome, regardless of health. These results broaden the understanding of echinoderm densoviruses outside the context of disease that suggest these viruses might form commensal or mutualistic relationships with their hosts.

UJI AKTIFITAS EKSTRAK METANOL BINTANG LAUT (Asterias forbesi) TERHADAP PERTUMBUHAN JAMUR Aspergillus sp. DAN Candida albicans SECARA In Vitro

Masalah kesehatan sering menimbulkan berbagai macam penyakit, beberapa penyakit banyak disebabkan oleh makanan yang terkontaminasi oleh jamur patogen. Beraneka ragam obat saat ini banyak mempunyai efek samping yang berbahaya bagi kesehatan. Pengobatan secara alami yang tidak menimbulkan dampak yang buruk bagi kesehatan manusia merupakan solusi untuk mengurangi efek samping salah satu yang berasal dari laut yaitu bintang laut (Asterias forbesi). Metode yang digunakan yaitu experimental laboratory. Tujuan dari penelitian ini untuk mengetahui zona hambat dan konsentrasi terbaik ekstrak metanol bintang laut (Asterias forbesi) terhadap pertumbuhan jamur Aspergillus sp. dan Candida albicans. Setelah dilakukan penelitian tentang uji efektifitas ekstrak metanol bintang laut (Asterias forbesi) terhadap pertumbuhan Aspergillus sp dan Candida albicans maka diperoleh bahwa ekstrak metanol Bintang Laut (Asterias forbesi) dapat menghambat pertumbuhan jamur Aspergilus sp. dan Candida albicans. Ekstrak metanol bintang laut 100% mampu menghambat pertumbuhan jamur Aspergilus sp. sebesar 0,88% dan Candida albicans sebesar 0,49%, ekstrak metanol 75% mampu menghasilkan diameter zona hambat sebesar 0,6% terhadap jamur Aspergilus sp dan 0,44% terhadap jamur Candida albicans. Pada konsentrasi 50% mampu menghambat pertumbuhan jamur Aspergilus sp sebesar 0,66% dan 0,42 pada jamur Candida albicans. Sedangkan pada konsentrasi terkecil yakni 25% menghasilkan kemampuan penghambatan yang lebih kecil yakni 64% dan 0,38% terhadap jamur Candida albicans.