47 However, the Brothers and nuns who feel that they are called to undertake such work must, before leaving their own country, acquire the professional training and knowledge which are today required in these matters. We know that there are nuns with full professional qualifications who have earned well merited recognition by the special study of loathsome diseases, such as leprosy, and by discovering remedies for them. These and all other missionaries who are giving their service so generously in leper hospitals, have Our paternal blessing, and their exalted charity compels Our admiration and praise.
Source: Evangelii Praecones (Vatican.va)