This pilot study in seven mares evaluated the effectiveness of a one-time insertion of a novel hormone/drug-free copper intrauterine device (CuiUPOD with one to three copper-coated magnetic units) in controlling Streptococcus zooepidemicus in intrauterine-inoculated mares. The setting involved: initially inserting one unit into each mare; weekly trans-rectal ultrasound; blood progesterone assay; uterine swabs for cytology and microbial culture; uterine specimens for biopsy; and trans-abdominal detection of the CuiUPOD using a handheld magnetic detector and/or a cell phone compass. The study was complemented with an in vitro experiment.
Infection persisted after a CuiUPOD with one magnetic unit was inserted, but subsided shortly after two additional magnetic units were used. By day 90, at device removal, and after a 30-day exposure to copper, all the mares presented no clinical signs of infection. Endometrial biopsies showed a grade improvement in two mares, but not significant (p >0.05), before and after CuiUPOD placement. The in vitro experiment demonstrated a time (24-96 hours) and dose-dependent response to Cu: three CuiUPODs - OD readings = 0.538; two CuiUPODs - OD = 0.513; and one CuiUPOD - OD = 0.452. As the concentration of copper increased, so did the antimicrobial effect. These findings suggest a promising use for the one-time application of a CuiUPOD with either two or three magnetic units to mitigate uterine infections in mares.