Evaluation of a male-specific DNA coliphage persistence within Eastern oysters (Crassostrea virginica)

Authors: Kingsley, David; CHEN, HAIQIANG - University Of Delaware; Annous, Bassam; Meade, Gloria

Submitted to: Food and Environmental Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2019
Publication Date: 4/30/2019
Citation: Kingsley, D.H., Chen, H., Annous, B.A., Meade, G.K. 2019. Evaluation of a male-specific DNA coliphage persistence within Eastern oysters (Crassostrea virginica). Food and Environmental Virology. 11:120-125.

Interpretive Summary: Male specific coliphages (MSCs) are viruses that infect the intestinal bacteria E. coli. They are used a research surrogates and as sanitary indictors to assess sewage impacts on shellfish beds. Since many MSCs have RNA genomes they are thought to be have much like HAV and human norovirus which also contain single-stranded RNA genomes of the same approximate size. Because of this similarity the DNA MSCs are often ignored. In this publication we evaluate the ability of a DNA MSC (M13 strain) to persist within oyster tissues. Results indicate that DNA and RNA MSCs may not be very much different with respect to persistence within shellfish.

Technical Abstract: Male-specific coliphages (MSCs) are currently used to assess the virologic quality of shellfish growing waters and to assess the impact of sewage release or adverse weather events on bivalve shellfish. Since MSC can have either DNA or RNA genomes, persistence of M13 a DNA male-specific coliphage was evaluated for its persistence as a function of time and temperature within Eastern oysters (Crassotrea virginica). Oysters exposed to seawater containing10,000,000,000 to 1,000,000,000,000 pfu of M13 for 24 hrs at 15 degrees C followed collective maintenance in continuously UV-sterilized water for up to 6 weeks at either 7, 15, or 22 degrees C were held for up to 6 weeks. Initial contamination levels greater than 1000000 pfu of M13. For oysters held three weeks log reductions were 1.7, 3.8, and 4.2 log at 7 15 and 22degrees C respectively. Oysters held at 7 and 15 degrees C showed average reductions of 3.6 and 5.1 log respectively, but still retained some infectious M13. In total, this work that DNA MSC may decline within shellfish in a manner analogous to RNA MSCs.