Simultaneous quantification of hepatitis A virus and norovirus genogroup I and II by triplex droplet digital PCR

The representative enteric viruses responsible for global foodborne outbreaks that have become an essential concern for health authorities are Norovirus (NoV) and Hepatitis A virus (HAV). Droplet digital PCR (ddPCR) has recently emerged as an alternative platform for virus quantification due to its high precision, ultra-sensitivity, and lack of a standard curve need. Using a ratio-based probe-mixing strategy, we established a triplex ddPCR method to detect norovirus genogroup I (GI), genogroup II (GII), and HAV in food, drinking water, and faecal samples. The probe concentration, annealing temperature, and annealing/extension time were all tuned in the PCR amplification program. The detection limit for NoV GI, NoV GII, and HAV was 7.5, 5.0, and 5.0 copies/reaction, respectively. Furthermore, the suggested approach was validated on 114 samples, demonstrating greater sensitivity, accuracy, and anti-interference performance features than RT-qPCR.