<i>Chlamydia pecorum</i>–Associated Sporadic Ovine Abortion

Abstract

Despite previous detection of <i>Chlamydia pecorum</i> in sporadic ovine abortions, published descriptions of naturally occurring infections with fetoplacental lesions are lacking. This report provides the first descriptions of severe necrosuppurative chorionitis with vasculitis, and fetal pyelonephritis and enteritis in late-term abortions of maiden ewes. Chlamydial infection was detected using a <i>Chlamydia</i> genus-specific qPCR (quantitative polymerase chain reaction) on tissue extracts from 3 fetuses. <i>C. pecorum</i> was identified using a targeted qPCR assay, which also determined infectious load within fetal tissues. The presence of viable <i>C. pecorum</i> in fetal samples was confirmed by cell culture. Multilocus sequence typing (MLST) data indicated that the <i>C. pecorum</i> strains from each fetus were identical and of sequence type (ST) 23. <i>Chlamydia</i> sp. immunohistochemistry showed strong positive immunolabeling of fetoplacental lesions. Other infectious abortigenic agents were excluded with specific testing. This report confirms <i>C. pecorum</i> as a likely cause of ovine abortion and provides the first descriptions of associated fetoplacental lesions in naturally infected sheep.