Yersinia enterocolitica has occasionally been isolated from sheep foetuses and has been isolated from both healthy and diseased livestock and man (Brewer and Corbel 1983). In sheep, Y enterocolitica caused a severe generalised bacterial infection of the foetus (Corbel et al 1990). The following report is of a case of placentitis and abortion in a maiden Boer doe, from which Yersinia enterocolitica was isolated from numerous tissues.
The owner of a small Boer goat flock contacted the first author on the 30th August 2012 after a second maiden doe experienced a late term abortion/stillbirth. The 20 ha property is located east of Kempsey in a low-lying region, which for the past 3 years has experienced above average rainfall and been very wet. The owners operate a small Boer goat stud, mainly supplying animals to other small farms in the region. There were 16 does due to kid, of which two had kidded without incidence and one maiden doe had had a stillborn kid 5 days previously. The second of three maiden does due had aborted twin kids that morning. The owner reported that the placenta from the first doe to abort appeared quite opaque.
Twin kids and placenta were presented for post mortem examination. Grossly the placenta appeared thickened and oedematous. Of the two foetuses one appeared much more autolysed than the other, suggesting that it may have been dead in utero for a couple of days. The liver in both foetuses appeared to be enlarged, with rounded margins. Samples were collected from the less autolysed foetus and submitted to the lab for culture and histopathology.
Histopathology revealed a diffuse, perivascular infiltrate of lymphocytes, neutrophils, abundant bacteria and areas of cellular coagulative degeneration. Infiltrates of lymphocytes, macrophages and neutrophils were also evident in liver and lung, while in the cerebrum there were mild numbers of lymphocytes in the meninges. Neutrophils were also noted in the circulation in the section of cerebrum examined.
A profuse pure growth of Yersinia enterocolitica was cultured from the liver, while profuse predominant growth of Y enterocolitica was cultured from lung and abomasal fluid. The laboratory findings are consistent with a suppurative placentitis and systemic inflammation associated with Yersinia enterocolitica infection.
At the time of writing, no further does had aborted, with 12 of the 16 having healthy live kids and two still to kid.
As Y enterocolitica (and Yersinia pseudotuberculosis) are carried in the intestinal tract of clinically normal animals, infection via the faeco-oral route seems most likely. Enteric yersiniosis caused by Yersinia pseudotuberculosis is frequently diagnosed in cattle in the Mid North Coast, particularly during wet winters, with cases mostly occurring in late winter and early spring. Cases of enteric yersiniosis in cattle had been seen and reported during August 2012.
It is presumed that Yersinia enterocolitica, like Y. pseudotuberculosis, has an increased survival time in the environment in wet, cool conditions. While rainfall in August in the region was negligible, rainfall earlier in the year had been above average and the property in this case had been quite wet in preceding months.
Yersinia enterocolitica is a zoonosis and has been associated with gastrointestinal disease in humans, with a reactive arthritis as an occasional sequel (Radostits 2000). This should be remembered when handling aborted foetuses.