Detection and quantification of Sapovirus in bivalve molluscs from Galicia (NW Spain).
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1
Universidad de Santiago de Compostela, Spain
Sapovirus (SaV), etiologic agent of human gastroenteritis, is a RNA virus from the Caliciviridae family, mostly detected in Asia. It has been classified by the U.S. Environmental Protection Agency as an emergent human pathogen with risk for public health in aquatic environments. Bivalves, due to their filtrating feeding, concentrate viral particles presented in seawater, and it has been demonstrated that the bioaccumulated viruses can resist depuration treatments to which bivalves are submitted. In addition, the traditional way of bivalve consumption increases the probability of infection, making them a high risk food [1].
The main objective of this work was to detect and quantify SaV in bivalves from Galicia, Northwestern Spain. A total of 168 samples, including mussels (Mytilus galloprovincialis), clams (Venerupis philippinarum and V. decussata) and cockles (Cerastoderma edule) were obtained during a period of 18 months from two Galician Rías (Ría of Ares-Betanzos and Ría of Vigo, respectively at North and South of the region). Samples consisted into 10 or 20 individuals, which were dissected under aseptic conditions to obtain their digestive tissue.
The viral RNA was extracted using Nucleospin RNA Virus Kit (Macherey-Nagel; Dürem, Germany). Subsequently, viral detection and quantification by real time RT-PCR was performed using Platinum Quantitative RT-PCR Thermoscript One-Step System Kit (Invitrogen, Saint Aubin, France), according to the recently developed standard method ISO/TS 15216:2013. Primers SaV124F and SaV124R, and probe SaV124TP designed to amplify human genogroups I, II and IV were used [2]. Both through viral RNA extraction and viral detection and quantification, internal controls were used to avoid false positive or negative results, and the possible presence of inhibitors.
SaV was detected in 30 of the 168 samples (17,85%). There was no significant difference between the two Rías in terms of detections, although it was observed a seasonality increment of positive samples from November 2011 until April 2012 in both Rías due to the rainy season and the decrease of seawater temperature. Total quantification ranged between 103 and 105 copies of viral RNA/g of digestive tissue (c/g), being mussels the specie with lower main quantification (3,1 x 104 c/g) and clams the species with higher medium rates (2,0 x 105 c/g). This represents the first study out of Japan in which human Sapovirus was detected and quantified into human food intended for consumption.
References
[1] G.S. Hansman, T. Oka, R. Okamoto, et al. Human sapoviruses in clams, Japan. Emerg Infect Dis, 13 (2007) 620-22.
[2] T. Oka, K. Katayama, G.S. Hansman, et al. Detection of sapoviruses by real-time reverse transcription-polymerase chain reaction. J Med Virol, 78 (2006) 1347-53.
Keywords:
Bivalve molluscs,
enteric viruses,
Sapovirus,
detection,
RT-qPCR
Conference:
IMMR | International Meeting on Marine Research 2014, Peniche, Portugal, 10 Jul - 11 Jul, 2014.
Presentation Type:
Poster Presentation
Topic:
AQUACULTURE
Citation:
Varela
MF,
Polo
D and
Romalde
JL
(2014). Detection and quantification of Sapovirus in bivalve molluscs from Galicia (NW Spain)..
Front. Mar. Sci.
Conference Abstract:
IMMR | International Meeting on Marine Research 2014.
doi: 10.3389/conf.fmars.2014.02.00126
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Received:
09 May 2014;
Published Online:
18 Jul 2014.
*
Correspondence:
Prof. Jesus L Romalde, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, jesus.romalde@usc.es