Quantitative RT-PCR Detection of Human Noroviruses and Hepatitis A Virus in Surface Water and Fresh Produce

Abstract

Vegetables can be considered as a vehicle for the transmission of human enteric viruses such as noroviruses (genogroups I and II) and hepatitis A virus (HAV) when irrigated with contaminated irrigation or when prepared by infected food handlers. In the current study, we investigated the presence of hepatitis A virus (HAV) and human noroviruses (genogroups I and II) in fresh produce and surface water used in cultivation of this produce using real-time PCR. Samples were collected from six different points in the Mansoura and Giza regions, Egypt. Our analysis showed that at least one virus was found in 41.6% (30/72) of surface water samples and 27% (13/48) of fresh produce samples. HAV (23/72) with a mean viral concentration = 4 × 106 genome copies/litter (GC/L) was the most frequently identified virus in surface irrigation water samples, followed by human norovirus genogroup II (HNoV GII) (15/72, with a mean concentration = 1.2 × 106 GC/L, and human noroviruses genogroup I (HNoV GI) (12/72, with a mean concentration = 1.4 × 104 GC/L). Additionally, HAV (10/48) with a mean concentration = 5.2 × 105 genome copies/gram (GC/g) was also the most frequently detected virus in the fresh produce samples, followed by HNoV GII (8/48, with a mean concentration = 1.7 × 104 GC/g), meanwhile HNoV GI (6/48) was less detected virus with a mean concentration = 3 × 103 GC/g. This work suggests a wide prevalence of human enteric viruses in surface irrigation waters and fresh produce, which is of concern when the fresh produce is eaten raw. Thus, Additional monitoring for viral pathogens in irrigation water and food is needed to increase produce safely.