Abortions, stillbirth, and neonatal deaths caused by Ureaplasma diversum in beef cattle in Uruguay

Ureaplasma diversum is an opportunistic Mollicute associated with reproductive losses in cattle. Reports of this disease are scarce in South America. This study documents three sporadic cases of U. diversum–associated abortion and/or stillbirth occurring in three different beef cattle herds, as well as a cluster of three neonatal losses affecting a fourth herd in Uruguay. Diagnosis was based on histopathological findings, PCR, and systematic exclusion of other major abortifacient pathogens. The cases of abortion/stillbirth had fibrinosuppurative and necrotizing placentitis and fetal bronchopneumonia, whereas neonatal cases presented mild polyarthritis, interstitial pneumonia, and, in one calf, multisystemic inflammation. Ureaplasma diversum was detected by PCR in the placenta and/or lung in all six cases, and intralesional localization of U. diversum was demonstrated, for the first time, by in situ hybridization in two abortion cases. PCR was also performed from endometrial samples taken by cytobrush from 80 cows in the herd with the cluster of cases of perinatal mortality, showing no differences (p = 0.56) in the presence of U. diversum between affected (20%, 8/40) and unaffected groups (15%, 6/40). These findings highlight U. diversum as an emerging cause of reproductive and early postnatal losses in beef cattle in Uruguay and justify the inclusion of PCR for this pathogen in the differential diagnosis in cases of abortion, stillbirth, and neonatal death.