Intruders, who were represented as vampires in posters were another object of attention in the fight against venereal disease: 'it is not the disease that kills, it is ignorance', 'Do not ask for advice about your illness from people who do not know anything about medicine' and 'Do not try to cure yourself with blood depuratives', were all messages that aimed to do away with the custom of self-cures and the entry of unqualified people into the profession.
También el tema de los intrusos, representados en el cartel como vampiros -¿o son los depurativos de la sangre?-, era objeto de atención en el cartelismo de la lucha antivenérea: "No es la enfermedad la que mata, sino la ignorancia", "no pidas consejo sobre tu enfermedad a personas ajenas a la medicina" y "no pretendas curarte ti mismo con depurativos de la sangre", mensajes todos que intentaban acabar con las prácticas de autocuración e intrusismo.