Fungal endometritis caused embryo loss in a maiden mare

A 6 year old, maiden, Standardbred mare was inseminated with chilled, extended semen (from same stallion) during 2 consecutive estrous cycles. Following first cycle insemination, traces (< 1 cm diameter) of fluid were occasionally detected in uterine body during routine transrectal ultrasonographic examination. Day after second cycle insemination, transrectal ultrasonographic examination confirmed ovulation and absence of uterine fluid. Thirteen days postovulation, she was reexamined for an early pregnancy diagnosis. Embryonic vesicle (9 mm) was detected in uterine body with no free fluid in uterus. At scheduled midpregnancy diagnosis (28 days postovulation), ~ 10 cm diameter, mainly hypoechogenic, fluid pocket with mixed echogenic contents was detected in uterine body. No uterine edema was detected and cervix was closed. Uterine lumen was initially lavaged with sterile saline, followed by 1 liter of sterile saline with 20 ml of white vinegar. Reflux from saline uterine lavage was turbid and included debris and round, “fluffy” white objects 1 - 3 mm in diameter. Samples from lavage were sent for laboratory identification. A smear was stained with ‘Diffquick’ and assessed in the examining area. Debris, epithelial and inflammatory cells, stout rodshaped bacteria, and nonfruiting fungal hyphae were detected. Multiple drug resistant Enterobacter aerogenes was identified in culture. A fungus was cultured, but not definitively typed, although it was suspected to be Acremonium spp. Mare was treated with prostaglandin F 2α analogue (125 µg) and oxytocin (10 IU) IM twice daily for 2 days, and reexamined 4 days later. Minimal (< 0.5 cm diameter) intrauterine fluid was detected. A clitoral swab was collected for fungal isolation, but was unrewarding. A double-guarded uterine swab was collected prior to next insemination, but culture results were unrewarding. She was inseminated again 26 and 58 days after diagnosis of fungal endometritis. She was diagnosed pregnant 14 days following second insemination. Mare had good perineal conformation with no previous history of intrauterine antibiotics or immunomodulating pharmacological (corticosteroids or NSAID’s) agents (considered risk factors for fungal endometritis). Putative fungus, Acremonium spp. is typically considered to be a plant associated symbiont or pathogen. Fungal endometritis is considered most likely reason for embryonic loss in this mare. To the authors’ knowledge, there are no reports of fungal endometritis as a likely cause of embryo loss (prior to 40 days) in mare.

Keywords: Mare, fungal endometritis, embryo, embryonic loss

This manuscript was originally published in the journal Clinical Theriogenology Vol 12(3) Sept 2020.  Clinical Theriogenology is the official journal of the Society for Theriogenology (SFT) and the American College of Theriogenologists (ACT).  This content has been reproduced on the IVIS website with the explicit permission of the SFT/ACT.