equine abortion due to streptococcus zooepidemicus

Streptococcusequisubsp.zooepidemicus (s.zooepidemicus) is a gram-positive, β-hemolyticcoccus belonging to the lancefield group c. it is an opportunistic pathogen for both humans and a broad range of animal species including horses, dogs, and pigs.as an opportunistic pathogen of horses؛ s. equi subsp. zooepidemicus not only colonizes mucosal surfaces but also causes a wide variety of diseases, such as pneumonia, arthritis, abortion, and wound infections. some outbreaks are limited to respiratory signs in the herd, but other outbreaks also have mares aborted due to the infection. streptococcusequizooepidemicus is oneofthemostfrequentcausesofinfectiousabortioninmares.theseinfectionsmayberestrictedtothefetal membranes or they may involve the fetal organs or fluids. a 9-month-old aborted fetus and placenta referred to the diagnostic laboratory for complete examination in order to determining abortion cause. although the fetus showed notable autolysis, pathological examination revealed serosanguinous fluid accumulation in body cavities, meningeal hyperemia, multifocal placentitis, mild pneumonia, hepatic sinusoidal hyperemia, hepatitis, kupffer cell hyperplasia in liver, submucosal neutrophilin filtration in intestine. tissue samples were cultured and streptococcus spp was isolated from placenta, liver, lung, kidney, heart, one marrow and gastric content. direct smear revealed cocci shape, gram positive bacteria were visible on the contact smears. abortion due to streptococcuszooepidemicus was diagnosed. antimicrobial susceptibility test clarified streptococcusequisubsp.zooepidemicus is sensitive to penicillin, ceftriax one and doxycycline. good hygiene and management practices prompt isolation of affected animals and early treatment should be helpful to control the disease in farms.