Outbreak of K99+ Escherichia coli Infection and Serological Survey in Calves

The isolation of K99 Escherichia coli (K99 E. coli) was performed using diarrheal stool which occurred in calves from january through October, 1988. Moreover, bacteriolgical examination of isolated K99 E. coli and the adherent condition of K99 antigen in the intestinal canal of a dead calf was observed. In addition an epidemiological survey mainly including antibody examination of adult cattle were made. Out of 50 cases of diarrheal stools collected from calves, 11 strains of K99 E. coli were isolated. The toxin-producing ability of K99 E. coli thus isolated was all ST-positive and LT-negative, and 0 antigen was 09 and 08 in 9 and 2 cases, respectively. The adhesion of K99 antigen in the intestinal canal was remarkable in the jejunum and ileum. K99 antibody examination of 100 cattle selected at random from 92 farms revealed that 34 adult cattle (34%) showed a more than fourfold antibody titer. The K99 antibody titer of those cattle belonging to the forms , where the diarrheal calves occurred, became positive in 6-9 months after the disease occurred.-J. Jpn. Vet. Med. Assoc., 43, 193•`196 (1990) .