Is Crohn’s disease going viral?

Is Crohn’s disease going viral?

Indrani Mukhopadhya

Norovirus capsid electron microscope image; source:’s disease (CD) is a chronic inflammatory disease that can involve any part of the digestive tract and affects more than 100,000 people in the UK and the incidence is rising. The normal gut contains 100 trillion microorganisms including bacteria, fungi and viruses: ten times more than the number of cells of the human body. Normally, the human immune system has a symbiotic relationship with these microorganisms. It is believed however that in CD patients the immune system loses the ability to distinguish microbial ‘friends’ from ‘foe’. This defect is coupled with an increase of more potentially harmful bacteria and causes the body to mount an attack against the bacteria, triggering inflammation of the bowel. The exact causes of CD are unknown and there is very little information on the viruses and fungi living in the gut.

Recent studies suggest that gut viruses outnumber bacteria ten to one. Although viruses such as norovirus cause CD-like disease in genetically susceptible mice and disease flares in CD patients, their exact role in disease onset has not been properly investigated. This study aims to characterise the entire population of microorganisms from faecal samples of CD patients and compare it with that of healthy individuals. This comprehensive assessment will use state-of-the-art sequencing technologies and will allow us to understand how viruses compete and interact with bacteria and fungi in CD patients.

The outcome of this research will contribute to a deeper understanding of the role of viruses in inflammatory diseases and help design preventive strategies against the development of CD.

Image source: Debbink K et al. (2012) PLoS Pathog 8(10): e1002921. doi:10.1371/journal.ppat.1002921