Sheep abortion outbreak - possibly Fusobacterium nucleatum

Authors: Hutton J
Publication: New Zealand Veterinary Journal, Volume 40, Issue 1, pp 35, Mar 1992
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Abortion/stillbirth, Bacterial, Diagnostic procedures, Reproduction, Disease/defect, Infectious disease, Reproduction - female
Article class: Abstract

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Abstract: A mid-Canterbury farmer had a 30-fold increase in sheep abortion in his 2950 ewe flock despite vaccination for campylobacter or toxoplasmosis.
Some 300 abortions occurred over 50 days, 70 in 2-tooths and 230 in older ewes. The “epidemic curve” was approximately a straight line with an average of 6 abortions per day. Samples from 32 lambs were submitted to the Lincoln Animal Health Laboratory. Despite exhaustive testing, no specific agent was consistently isolated. Low positive titres to the Toxoplasma Latex Agglutination test were found in 2/28 samples of foetal heart blood. Campylobacter jejuni was isolated from 1/27 foetal stomach contents cultured. No other significant bacteria was isolated. In four lambs liver lesions were seen. These were focal necrotic grey-yellowish lesions 2-10 mm in diameter - similar to lesions recorded in cases of campylobacter abortions - but we were unable to isolate campylobacter from any of these lesions. Cotyledons were submitted infrequently. Histopathological examination showed a placentitis with bacteria present in the chorionic villi. On initial examination the bacterial colonies resembled campylobacter infections but on closer examination the bacteria appeared variable in shape and size. The organisms stained poorly with Gram stain (lightly Gram-negative) and stained better with Giemsa stain. They appeared as tapered rods with some beading. In North America, sporadic sheep abortions have been associated with Fusobacterium nucleatum infection. The liver lesions, placentitis and bacterial features described were similar to those seen in this case. The organism is a fastidious anaerobe with strict growth requirements. We were unable to isolate Fusobacterium nucleatum in this case.

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