This common virus may contribute to the latest Crohn’s research as it can help scientists understand how Crohn’s disease manifests.
What is Norovirus?
Noroviruses are a genus of viruses in the Caliciviridae family. The Center for Disease Control considers noroviruses to be the most common cause of foodborne illness, with an estimated 23 million norovirus infection per year in the U.S. alone. It’s calculated that noroviruses are behind 95% of viral outbreaks causing epidemic gastroenteritis—inflammation of the stomach and intestines, which, in the case of noroviruses, can include symptoms of vomiting, stomach pain and diarrhea over a period of 1-3 days. This pathogen is highly contagious, classified by the CDC as Category B biodefense agents. Not only are noroviruses stable in their environment, but they are also resistant to common disinfectants.
How Do You Get Norovirus?
Noroviruses are highly contagious and can spread easily through a number of channels: contaminated food and water, from person-to-person contact, through the air via particles of vomit, and from exposure to fomites.
It’s common to see norovirus outbreaks in semi-closed groups such as nursing homes, military settings, schools, hospitals, and cruise ships.
In healthy adults, norovirus infections incubate quickly, with symptoms showing up within 12 hours and lasting as long as 3 days. Symptoms typical of norovirus-induced gastroenteritis include vomiting, diarrhea, nausea, abdominal cramps, and low-grade fever. While these resolve within a few days in healthy adults, in certain risk groups (young children, elderly individuals) a norovirus infection can lead to a more severe and prolonged norovirus-induced disease.
How Norovirus May Help Understand Crohn's
How can studying the norovirus pathogen contribute to Crohn’s research?
An article published in a Science issue of April 2018 revealed information on the type of cells that noroviruses target, shedding light on how the norovirus interacts with its host. The researchers found that, in mice, a specific type of cell in the gut lining called “tuft cells” showed evidence of infection by the norovirus.
Tuft cells, also called brush cells due to the presence of the microvilli on the cell surface, are found in the epithelial layer of the intestine and respiratory tract. Researchers who study these cells believe that they provide clues to both the origin of certain diseases and the therapies to treat them.
Crohn’s Disease: New Treatment?
As scientists work to develop new drugs for Crohn’s disease, they seek an understanding of what causes Crohn’s disease. So far, no one knows the exact Crohn’s disease cause, but the latest Crohn’s research has suggested that an outside trigger, such as an infection, may cause the disease to manifest in individuals who are already slightly more likely to develop Crohn’s because of their genes.
Combined with work from other studies, the findings from this study contribute to new Crohn’s research by illustrating the potential role of tuft cells in the triggering of Inflammatory Bowel Disease like Crohn’s and colitis. In a separate study, researchers observed that the onset of Crohn’s disease in mice can be triggered by a norovirus infection. These findings suggest that, for Crohn’s, new treatments might be made more effective by targeting tuft cells, following the same pathway as a norovirus infection.
Recent advances in the study of noroviruses has helped scientists to understand their structure and pathway through the body—now, researchers are developing a cell culture system and understanding the design of norovirus clones. Perhaps, the latest research on IBD and noroviruses will enable scientists to target the disease through an entirely new approach.
IBD.Lencioni, K. C., Seamons, A., Treuting, P. M., Maggio-Price, L., & Brabb, T. (2008). Murine Norovirus: An Intercurrent Variable in a Mouse Model of Bacteria-Induced Inflammatory Bowel Disease. Comparative Medicine, 58(6), 522–533. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2710753/)
Karst, S. M. (2010). Pathogenesis of Noroviruses, Emerging RNA Viruses. Viruses, 2(3), 748–781. http://doi.org/10.3390/v2030748
Cunningham, Aimee. (2018 April 13) This is how norovirus invades the body. ScienceNews. Society for Science & the Public. Retrieved from https://www.sciencenews.org/article/how-norovirus-invades-body)
Reid, L., Meyrick, B., Antony, V. B., Chang, L.-Y., Crapo, J. D., & Reynolds, H. Y. (2005). The Mysterious Pulmonary Brush Cell: A Cell in Search of a Function. American Journal of Respiratory and Critical Care Medicine, 172(1), 136–139. http://doi.org/10.1164/rccm.200502-203WS