Signalment (JPC #2015774):  A cross-bred ewe

HISTORY:  A flock of cross-bred ewes experienced an abortion outbreak with 40% of the ewes affected.  The aborted fetuses were near-term and in a fresh state. 

HISTOPATHOLOGIC DESCRIPTION:  Chorioallantois: There is diffuse loss of chorionic villar architecture with replacement by abundant eosinophilic cellular and karyorrhectic debris (necrosis), hemorrhage and viable and degenerate neutrophils with fewer macrophages and concretions of intensely basophilic granular material (mineral), which expands the intervillous space.  Still attached and sloughed trophoblasts, scattered throughout the necrotic debris  are often markedly expanded by numerous indistinct intracytoplasmic, amphophilic, 1 um diameter cocci admixed with small amounts mineral. Multifocally within the chorioallantoic connective tissue, blood vessel walls are infiltrated by eosinophilic karyorrhectic debris, neutrophils and scant amounts of fibrin which expand the tunica intima and media (necrotizing vasculitis).  Vascular lumens are multifocally variably occluded by fibrin thrombi.  There are perivascular accumulations of viable and degenerate neutrophils with fewer macrophages, lymphocytes and plasma cells.   Within the chorioallantoic stroma there are low numbers of previously described inflammatory cells as well as increased clear space and dilated lymphatics (edema). The intercotyledonary chorion is ulcerated or lined by epithelium that is degenerate or necrotic, with epithelial cells occasionally containing amphophilic, 1 um diameter cocci.  The surface and underling stroma contain variable amounts of necrotic debris and mineral admixed with neutrophils, lymphocytes and plasma cells.

MORPHOLOGIC DIAGNOSIS:  Chorioallantois:  Placentitis, necrosuppurative, diffuse, severe, with vasculitis, and intratrophoblastic cocci, consistent with Chlamydia abortus, cross-bred sheep, ovine.

ETIOLOGIC DIAGNOSIS:  Placental chlamydophilosis

CAUSE:  Chlamydophila abortus

CONDITION:  Ovine enzootic abortion or Enzootic abortion of ewes (EAE)











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