Hepatitis A Virus PCR Analysis and E. coli Detection in Oysters at Oualidia Lagoon and Their Correlation

Abstract

The present study aims to evaluate hepatitis A virus (HAV) prevalence and faecal contamination indicators Escherichia coli (E. coli) in oysters from Oualidia lagoon (Moroccan Atlantic coast) and to study the correlation between the two parameters. The survey was carried out on 87 samples of oysters (Crassostrea gigas) collected monthly between November 2015 and February 2017 from three sites corresponding to different oyster farms in the lagoon. Sanitary status of bivalve molluscs was assessed by E. coli enumeration using ISO 16649-3. Detection of hepatitis A virus, was carried out by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) according to ISO 15216-2 method. The prevalence of samples for which E. coli contamination exceeds the threshold of 230 E. coli/100g of flesh and intravalvular fluid (FIF) is 43%. HAV RNA was detected in 2% of the samples analyzed. This RNA was even detected in a sample meeting the bacterial criteria. Viral health surveillance of bivalve molluscs is therefore necessary before their delivery for human consumption.