The parasite, Neospora caninum is an important cause of abortion in cattle. It is transmitted vertically or horizontally and infection may result in abortion or the birth of a live, healthy but infected calf at full-term. Only a proportion of infected cattle abort and the pathogenesis of abortion is not understood. Groups of cattle were infected with 10(7) N. caninum tachyzoites intravenously at different times relative to gestation. Intravenous inoculation was chosen to reproduce the putative haematogenous spread of N. caninum following either recrudescence of endogenous infection or de novo infection. In all cattle, infection was accompanied by high gamma-interferon and lymphoproliferative responses, and a biased IgG2 response indicating that N. caninum infection is accompanied by a profound Th1 helper T cell-like response. Infection at 10 weeks gestation resulted in foetopathy and resorption of foetal tissues 3 weeks after infection in 5 out of 6 cows. Infection at 30 weeks gestation resulted in the birth of asymptomatic, congenitally-infected calves at full term in all 6 cows, whereas the 6 cows infected before artificial insemination gave birth to live, uninfected calves. These results suggest that the reason some cows abort is related to the time during gestation when they become infected or an existing infection recrudesces.

We present a case of a 34-year old G1P0 female with twin-gestation and positive prenatal screening. Initial ultrasounds demonstrated a normal live fetus with an indeterminate but persistent placental lesion. The patient presented at 23 weeks of gestational age with vaginal bleeding. On examination, a 2 cm vaginal lesion was identified. Further cross-sectional imaging demonstrated a normal appearing fetus with a mixed solid and cystic placental lesion as well as an additional lesion in the vagina. Metastatic workup revealed diffuse pulmonary metastases. Intravascular embolization was carried out to minimize the bleeding from the vaginal lesion, followed by the delivery of the fetus with an urgent Caesarean section and treatment with chemotherapy. Pathology and genetics testing confirmed diagnosis of a complete molar pregnancy with a coexisting live fetus. This case highlights the importance of any unexpected findings within the placenta or the uterus in a pregnant patient. The radiologist should maintain a high index of suspicion for gestational trophoblastic disease in such cases, communicate clearly with the clinical team and suggest appropriate additional imaging.

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