Fetal death and resorption during the course of equine viral arteritis

The study was carried out on an Anglo-Arab horse stud "O" at which 186 horses were kept including 67 brood-mares and 8 stallions. During tne 1991 breeding season the semen from the four stallions was used for insemination. At the begining of April 1991, insemination with semen from the stallion ARC, who was brought to the stud "O" a month earlier, was carried out. About seven days later, fever (39.5 - 40.5°C) and anorexia appeared in some of the inseminated mares. In most of the feverish mares, edema of eyelids and reddening of conjunctivas were also found. Two mares aborted after 3-4 months of gestation. Gynecological examination with an ultrasonograph was performed three times: before, at the begining and after the enzootic of Equine Viral Arteritis and showed permanent increase of embrionie death and resorption up to 31.8%. From tissue samples of two aborted fetuses and ARC's semen Equine Arteritis Virus was isolated. In serological examination for the presence of neutralizing antibodies against EAV conducted in 1989 on a group of 71 horses from the stud "O", 9.8% positive reactions were found. Subsequent serological examination performed on a group of 186 horses in 1991 after introduction of the stallion ARC to the stud revealed that 67.7% of animals were positive for EAV antibodies.