Design and preliminary application of a set of highly sensitive universal RT-PCR primers for detecting genotype I/IV hepatitis E virus
Genomic sequences of genotypes I, II, III and IV of hepatitis E virus were aligned and the conserved region was selected for designing a set of reverse-transcription polymerase chain reaction (RT-PCR) primers, which were denominated as E promers. The sensitivity of E primers and three sets of reported primers (Meng, ConORF1 and ConORF2) were compared by using HEV genotypes I and IV challenged monkeys' stools and sera of hepatitis E patients. The detection limit of E primers for genotype I HEV in monkey stools was 10 to 1000 times lower than that of reference primers, and the same or 10 times lower than that of reference primers for genotype IV HEV. When amplified by RT-PCR using E primers, five out of seventeen (29.4%) anti-HEV IgM positive patients' sera were positive, and just 1 or 2 samples were positive when RT-PCR were performed using reference primers. Thus, the E primers would be a better choice for detection of HEV RNA in samples from China, where only genotype IV and genotype I HEV were reported.