Diagnosis of placental pathogens in small ruminants by immunohistochemistry and PCR on paraffin‐embedded samples

Abstract

A histological study was carried out on 58 formalin-fixed and paraffin-embedded samples of placenta from sheep and goats that had aborted, and the placental lesions were graded. Sequential histological sections of each cotyledon were then immunostained with specific antibodies and used for PCR detection of Chlamydophila abortus, Coxiella burnetii, Salmonella Abortusovis, Brucella melitensis, Listeria monocytogenes and Toxoplasma gondii. Most of the cotyledons showed different degrees of placentitis. The proportional agreement between the two techniques was 0.879 (kappa value 0.746). C abortus was the most prevalent pathogen. Mixed infections were common.

Multivariate model for the assessment of risk of fetal loss in goat herds

“…The pathogen is experimentally proven to cause abortions (Rodolakis et al 1984) and has been frequently isolated from clinical cases of abortions in goats (Moeller 2001, Szeredi et al 2006, Navarro et al 2009). Epidemiological confirmation of its role in fetal loss, given that apparent herd-level prevalence was very small, seems to be very important information and raises concerns as to the situation in forthcoming years.…”

Theriogenology of Sheep and Goats

“…55 Because C. abortus often affects only the placenta, histopathologic examination, culture, and PCR analysis of fetal tissue may be unrewarding. 56,57 Sensitivity of PCR assay decreases the longer tissues are stored in formalin. 6,10 Immunohistochemistry studies or PCR assay performed on formalin-fixed paraffin-embedded placenta is a less sensitive backup method if fresh tissue is not available.…”

“…3 Fluorescent antibody testing can be used to identify the organism in frozen placental sections. 57 Even though a variety of serologic tests have been described, a diagnosis of C. burnetii abortion cannot be given solely on the basis of positive results on such testing, because infections without abortion are common. 72 Gimenez or Wolbach's Giemsa stains of histologic sections of cotyledons or fetal abomasum are useful for observing the organism.…”

“…95 Serologic testing alone may lead to a false diagnosis. 57,97 6 The milk ring test is an agglutination test conducted on milk samples.…”

“…A high mortality rate among ewes after abortion has been described. 57 Specific agglutinins can be demonstrated in the sera of adults and aborted fetuses. 12 Salmonellae proliferating in the amniotic fluid may cause fetal pneumonia through amniotic inhalation or septicemia (Figure 8-33).…”