HEPATITIS A virus (HAV) is one of the most widespread foodborne pathogens and the cause of viral hepatitis. Fresh foods can be considered as a vector of transmission for HAV when contaminated by spoiled irrigation water or when prepared by infected food handlers. To improve microbiological detection and to increase insights into the contribution of fruit and vegetables to foodborne viral transmission, sensitive and standardized methods are needed. Two outlet drainage water samples from El-Mariotia and El-Gable Elasfar canals (Nile River) were collected in each month starting from March 2015 over a period of 12 months. As well as vegetables and fruit samples (lettuce, green onion and strawberry) were irrigated and washed with drainage water were also collected. Samples were extracted and concentrated for viral analysis. Strawberry and lettuce foods collected from El-Mariotia and lettuce from El-Gable Elasfar gave positive serological results by enzyme-linked immunosorbent assay (ELISA) test.
Reverse transcription polymerase chain reaction (RT-PCR) was successfully used to detect the virus in strawberry and lettuce samples using HAV-specific primers, designed to amplify a 500 bp fragment covering VP1/2A gene in HAV. The VP1/2A gene was sequenced and the nucleotide sequence similarity was in the range of 95- 99.1% between HAV-Eg isolate and 30 HAV sequences retrieved from GenBank. Phylogenetic analysis revealed that HAV-Eg isolate was grouped into a clade comprising Egyptian HAV isolates sub-genotype IB. Phylogenetic tree of nucleotides sequence showed that HAV sub- genotype IB is the circulating strain. |
