The reference to St James suggests convergence rather than clade. There are a heck of a lot of hospitals, all over, named after him. This is intriguing:

http://www.rushdenheritage.co.uk/health/StJames%27-hospital.html

as it suggests a specific link with leper hospitals. Syphilis and leprosy were always distinguished in popular culture, but they may well have been seen as related. (OK, what traditional songs about leprosy are there?) Though the patron saint of both syphilis and leprosy is St George.

BTW there is a version of the "Lovely Joan" story in Canteloube's "Songs of the Auvergne" - easily accessible if you're already including that one, and makes the point that the stories told by songs are no nation's property.

La pastoura als camps

(The text and translation are in the sleeve notes of the Netania Davrath recording; Monique here will know more about it).