Equine amnionitis and fetal loss: The case definition for an unrecognised cause of abortion in mares

Abstract

A series of abortions occurred in mares in New South Wales during 2004 that involved similar and unusual findings on post mortem examination of aborted fetuses and fetal membranes. The term Equine Amnionitis and Fetal Loss (EAFL) was developed to describe the condition. This form of abortion had not been previously recognised in Australia. The pathology alone is not specific for EAFL and diagnosis requires demonstration of a combination of certain pathological and bacteriological features. The purpose of this paper is to describe patterns considered consistent with EAFL cases as a working case definition for use by veterinarians and veterinary pathologists in identifying future cases of EAFL. More detailed papers are in preparation to fully describe the epidemiological, histopathological, and microbiological aspects of EAFL.

The guinea pig as a model for Equine Amnionitis and Fetal Loss (EAFL)

“…The placental membranes showed an unusual pattern of inflammation. The umbilical cord of aborted fetuses was discoloured, thick and oedematous sometimes with focal diphtheritic membranes (Todhunter et al, 2009). Vascular engorgement, oedema, beading of the vasculature and haemorrhages were the typical features of the amnion in all of the abortions.…”

“…Acute cases were often associated with almost 'no changes or haemorrhage on the pleura and amnion or sometimes with mild interstitial oedema of the lungs, generalised vascular engorgement or some haemorrhage of the umbilical cord' (Todhunter et al, 2009, p.36). Fetuses of younger gestational age were more likely to be associated with acute cases while fetuses of older gestational age more likey in subacute to chronic cases (Todhunter et al, 2009). The placental membranes showed an unusual pattern of inflammation.…”

“…The term Equine Amnionitis and Fetal Loss was adopted to describe the syndrome (Todhunter et al, 2009). Some clinical and pathological findings of EAFL resembled those of MRLS (Perkins et al, 2007).…”

“…The value represents the frequency of isolation of each type of bacteria from the given site as a percentage of the total number of sites tested across all treated guinea pigs……...57 Table 4.9: Experiment 3. The sites from which bacteria were isolated as a percentage of the number of sites from total number of sites tested across all treated guinea pigs…….....57 New South Wales as well as Queensland and Victoria in Australia (Todhunter et al, 2009). This unusual form of abortion, which came to be known as equine amnionitis and fetal loss (EAFL), had not been previously recognised in Australia (Todhunter et al, 2009).…”

“…The sites from which bacteria were isolated as a percentage of the number of sites from total number of sites tested across all treated guinea pigs…….....57 New South Wales as well as Queensland and Victoria in Australia (Todhunter et al, 2009). This unusual form of abortion, which came to be known as equine amnionitis and fetal loss (EAFL), had not been previously recognised in Australia (Todhunter et al, 2009). The name represents the typical features of this form of abortion.…”