Funisitis associated with leptospiral abortion in an equine placenta.

Funisitis, inflammation of the umbilical cord, is well recognized in human placentas. This report describes a case of funisitis associated with leptospiral infection in the placenta of a Thoroughbred foal born prematurely. The umbilical cord had diffuse superficial yellow discoloration along its entire length. Microscopic evaluation showed an exudate of neutrophils admixed with fibrin on the surface. Warthin-Starry staining showed spirochetes in the Wharton's jelly of the umbilical cord. A locally extensive, severe placentitis not involving the star and allantoic cystic hyperplasia were the other lesions observed in the allantochorion. Leptospira funisitis is similar to the funisitis of congenital syphilis in humans, although there are some major microscopic differences. In Leptospira funisitis, lesions were limited to the cord surface, whereas in lesions in human umbilical cords with Treponema pallidum infection, the changes are observed mostly around the vessels and in the Wharton's jelly.