From August through December in 1988, edema disease sporadically broke out in piglets 30-43 days of age raised on three pig farms within the juris diction of Ehime's Chuo Livestock Hygiene Service Center, and pathological and bacteriological examinations were carried out.
A bacteriological examination was carried in 7 dead animals which had been diagnosed as edema disease from the clinical signs and pathological findings and in one slaughtered case according to the results of a diagnostic test, and
Escherichia coli was isolated from the small intestines at the ratio of 10
7-10 cfu/g. Serotype of the isolates turned out to be 0139 and these bacteria were found to produce Vero toxin. Furthermore, this toxin was identified as VT2vp by a DNA hybridization test using beads-ELISA and an oligonucleotide probe.
From these findings, VT2vp-toxigenic
Escherichia coli was considered to be a causative organism of swine edema disease. In addition, since some pigs having VT2vp-toxigenic
Escherichia coli were confirmed, it was suggested that these carriers could possibly be an infection source. The present study is the first to isolate VT2vp-toxigenic Escherichia coli from pigs with edema disease or healthy pigs in Japan.
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