Why is our client having chronic diarrhea, which has been happening for the last three years? What will help?

This is a consequence of a chronic viral infection as you saw intuitively. The fact you have seen several such individuals quite recently and this client comes along is not your inner bias based on that recent experience, it is what it is. Of the many possibilities, diagnostically speaking, from a medical science perspective, it could be given other names and would be by physicians should she seek medical treatment at some point. But in all cases, regardless of the nomenclature and the so-called scientific perspective, the true cause of her symptoms is needing to fight the chronic presence of a viral invader, and the front line is the lining of the gut. This has some karmic predisposition and that is what has enabled this to take hold. It is usually the case, because otherwise the prevalence of this disorder would be much more widespread because almost all humans, eventually, are exposed. So it is those with compromised immune systems or who have a karmic predisposition for gastrointestinal issues who will become symptomatic and then have a chronic problem. In many cases that can become lifelong and sometimes quite severe. This should be handled quite nicely by getting work started on her behalf with the Lightworker Healing Protocol and to treat her G.I. symptoms as a key client issue, to request not only their cessation but removal of harmful virus from her system, and that will do the job nicely.