Streptococcus ovis associated abortion in an Icelandic mare.
Authors: Agerholm J S, Damborg P, Christoffersen M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Streptococcal species are recognised causes of equine abortion, typically ascending from the lower genital tract following cervical compromise, though *Streptococcus ovis*—a pathogen predominantly associated with ovine inflammatory disease—had not previously been documented in equine cases. This case report describes isolation of *S. ovis* in pure culture from the lungs of an 8-month-old fetus, where it had triggered acute suppurative bronchopneumonia alongside umbilical cord cellulitis and localised placentitis in the cervical star region. The clinical scenario involved a pregnant mare housed alongside sheep, with pregnancy status unknown at the time a double-guarded uterine swab was inserted into the cervical canal one week prior to abortion—a procedure that likely disrupted the cervical mucus plug and provided a route for ascending bacterial colonisation. The findings highlight two important practice considerations: firstly, that housing pregnant mares with small ruminants carries potential zoonotic disease risks via shared pathogenic organisms, and secondly that cervical instrumentation, even with guarded swabs, carries real risk of introducing infection if pregnancy status is unconfirmed. Whilst ovine streptococci are not primary equine pathogens, this case demonstrates how both environmental exposure and iatrogenic cervical trauma can create conditions for opportunistic infection and subsequent fetal loss.
Read the full abstract on PubMed
Practical Takeaways
- •Verify pregnancy status before performing any uterine procedures; cervical mucus plug damage can allow pathogenic bacteria to ascend even without obvious signs of pregnancy
- •Consider S. ovis as a potential abortifacient in mares with access to sheep, particularly following any cervical instrumentation
- •Pasture management with mixed species (equine-ovine) may increase exposure risk to ovine pathogens in pregnant mares
Key Findings
- •Streptococcus ovis, a pathogen previously unreported in horses, was isolated in monoculture from an 8-month-old equine fetus causing acute suppurative bronchopneumonia and placentitis
- •Cervical mucus plug disruption via uterine swab insertion one week prior to abortion likely facilitated transcervical bacterial migration from lower genital tract to pregnant uterus
- •S. ovis colonization resulted in multi-site fetal infection including lung, umbilical cord, and placental cervical star region