While IBS is not contagious, it has been linked to previous gastrointestinal infections. While most people make a full recovery after suffering from an intestinal illness, like acute gastroenteritis, some people go on to develop IBS. This condition is called post-infectious IBS. Post-infectious IBS is a type of IBS that is caused by a viral infection, a bacterial infection_ or a parasitic infection of the gastrointestinal tract. It is estimated that 5 - 30% of all IBS cases are PI-IBS.