Which Treponema pallidum subspecies is associated with congenital infections?

Which Treponema pallidum subspecies is associated with congenital infections?

• A. Treponema pallidum subsp pertenue
• B. Treponema pallidum subsp pallidum
• C. Treponema pallidum subsp endemicum
• D. Treponema pallidum subsp carateum

Answer: (B)

The key idea is that congenital infections are linked to the subspecies pallidum, the human venereal syphilis agent. Treponema pallidum subsp pallidum can be transmitted from an infected pregnant person to the fetus across the placenta, leading to congenital syphilis with potential fetal or neonatal complications. The other subspecies cause nonvenereal treponemal diseases—yaws (pertenue), bejel (endemicum), and pinta (carateum)—and are not typically associated with congenital transmission. So, Pallidum is the subspecies associated with congenital infections.

The key idea is that congenital infections are linked to the subspecies pallidum, the human venereal syphilis agent. Treponema pallidum subsp pallidum can be transmitted from an infected pregnant person to the fetus across the placenta, leading to congenital syphilis with potential fetal or neonatal complications. The other subspecies cause nonvenereal treponemal diseases—yaws (pertenue), bejel (endemicum), and pinta (carateum)—and are not typically associated with congenital transmission. So, Pallidum is the subspecies associated with congenital infections.