Bacteria:
Streptococcus zooepidemicus, Pseudomonas, Streptococcus genitalium

• Placental and fetal lesions.
• Bacteria, common in agricultural practices, are introduced via the cervix and causes an inflammation of the placenta, amniotic fluid may be cloudy.
• Placental and fetal infection can be low grade and the fetus born alive but ill.

• Mild illness 1 to 3 weeks before abortion
• Usually midterm abortions
• May be a factor in 20% of abortions

• Most important cause of infectious abortion.
• Virus capable of causing respiratory, nervous and fetal/perinatal disease.
• Mares often contract from foals but there are often no symptoms.
• Virus multiplies in lungs, spreads to circulatory system and eventually to the placenta and fetus.
• Abortion occurs 1 to 4 months after initial infection. Abortion usually 7 month to term.

Vaccinate mares before breeding and with killed EHV-1 at 5, 7, 9 month of gestation.

• Abortion occurs a few days after the initiation of clinical disease (fever,leukopenia, conjunctivitis, nasal discharge, and vascular necrosis)
• Abortion caused by anoxia of fetus and decreased progesterone by injured placenta.

Vaccination available for mares being breed to carrier stallions. Isolate mare for 21 days after breeding

• Inflammation of the chorion
• Invades vagina and uterus or may enter via the blood stream
• Placenta and fetus gross appearance like bacterial abortions