Which organism is associated with the disease known as bejel?

The organism associated with bejel is T. pallidum. Bejel is a non-venereal endemic syphilis-like infection primarily found in certain geographic regions and is transmitted primarily through skin contact rather than sexual intercourse. T. pallidum, which is also responsible for causing syphilis, has several subspecies that are responsible for different diseases.

In the context of bejel, T. pallidum specifically refers to the bacterium causing the disease characterized by cutaneous lesions and systemic manifestations. Other options listed refer to different forms of treponemal infections. For instance, T. carateum is associated with pinta, a skin disease that presents differently from bejel, while T. pertenue is responsible for yaws, an infectious disease that typically causes skin, bone, and cartilage lesions, primarily affecting children in tropical areas. T. vivax is not typically referenced in this context as it does not belong to the treponemal group related to human diseases.

By understanding these associations, it becomes clear why T. pallidum is the correct answer regarding its link to bejel, differentiating it from the other Treponema species that cause distinct conditions.