Development of an ex vivo model to study the zoonotic transmission of noroviruses

Human noroviruses are the most common cause of viral gastroenteritis worldwide, causing sporadic cases and outbreaks. Genetically related animal noroviruses infect wild and domestic animals including pigs and dogs. To investigate the potential of noroviruses to jump the species barrier, we used porcine, canine, and avian precision-cut intestinal slices. We show that human norovirus can bind to pig and dog intestinal tissue and be taken up with a similar efficiency as the porcine and canine noroviruses, respectively. In contrast, no binding or internalization of human, porcine, or canine noroviruses was detected in chicken tissue. We further showed that human norovirus can replicate to some degree in pig intestinal tissue, infecting single cells. In contrast, while animal noroviruses attached to human intestinal cells, intracellular uptake was limited. This suggests that human-to-animal transmission is more likely than animal-to-human transmission and that viral uptake likely presents a species barrier.