Ecology, Environment and Conservation Paper

INVESTIGATING OF NOROVIRUS GENOGROUPS I AND II USING BIVALVE MOLLUSCS BIOMARKERS FROM THE WILD LAGOON

Fatima Tarek, Abdelouaheb Benani, Najwa Hassou, Hlima Bessi and Mustapha Ennaji1

Abstract

Noroviruses belonging to the genogroups I and II (GI and GII) are the leading cause of human gastroenteritis worldwide. Faecal oral transmission is the main route of their spread among people, whereas environmental contamination occurs by transport of contaminated water. Studies on environmental contamination by noroviruses are routinely done using shellfish. Indeed, these filter feeders can accumulate and concentrate particles, such as viruses, in their digestive gland, and therefore, they are good indicators of viral pollution in aquatic environments. The aim of this study was to evaluate viral contamination by norovirus GI and GII in an important touristic lagoon in Morocco. To this aim, molluscan bivalves has been used as environmental biomarkers, local clams (Venerupis decussate; n=48 samples) and cockles (Cerastoderma edule; n=48 samples) were collected weekly during 12 months, from September 2016 to August 2017. Shellfish samples were processed according to the protocol described in ISO/TS 15216-2(standardized method for the detection of norovirus GI and GII), and then analysed by one-step real time RT-PCR using primers that target the capsid protein gene. This analysis showed the presence of norovirus GII in 6.25% (3/48) of clam samples, but in none of the cockle samples. As the PCR efficiency was not evaluated by artificial contamination (inoculation of known amounts of Mengovirus bacteriophage or other viral material), it is difficult to know the real level of shellfish contamination. A qualitative study on norovirus contamination could give information on the circulation of noroviruses strains in Moroccan aquatic environments and also on the hygienic conditions in wild areas.