Prevalence and Genetic Diversity of Human Sapoviruses in Shellfish from Commercial Production Areas in Galicia, Spain

Abstract

ABSTRACT The prevalence of human forms of Sapovirus , an emerging pathogen of human gastroenteritis, was investigated in an 18-month survey from class B mollusc-harvesting areas in two Galician rias (northwest Spain). The detection and quantification of Sapovirus was performed by reverse transcription-real-time PCR, according to the recently developed standard method ISO/TS 15216-1:2013, and genotyping by reverse transcription-nested PCR. The bivalve species studied were wild and cultured mussels ( Mytilus galloprovincialis ), clams ( Venerupis philippinarum and Venerupis decussata ), and cockles ( Cerastoderma edule ). Sapovirus was detected in 30 out of 168 samples (17.9%), with cockles being the species with the highest prevalence of positives (28.1%), followed by clams (22.6%), wild mussels (14.3%), and cultured mussels (12.9%). The estuary in the south of the region demonstrated a higher percentage of positive samples (21.8%) than the one in the north (14.4%). Viral contamination levels for the positive samples ranged between 1.9 × 10 3 and 1.4 × 10 5 RNA copies/g of digestive tissue. Thirteen Sapovirus sequences could be obtained based on partial capsid gene sequence and were classified into four genotypes: GI.1 (2 samples), GI.2 (8 samples), GIV.1 (2 samples), and GV.1 (1 sample).