Enteritis of Early Weaned Pigs : II. Pathogenesis.

Strains of hemolytic E. coli are implicated in edema disease and enteritis of swine. Immunological experiments were conducted to determine the specific role played by hemolytic E. coli in the etiology of these diseases. When cell-free extracts prepared from a frequently isolated E. coli - 0139:K82(B) were injected 48 hours apart into a healthy pig, symptoms of edema disease were produced on both occasions. Similar symptoms were produced when this extract was injected into a colostrum-deprived pig raised in isolation. The Schultz-Dale reaction revealed no difference between the contractions of the ilea of sensitized and non-sensitized guinea-pigs. In vitro treatment of a single non-sensitized guinea-pig uterus with extracts of five different strains of hemolytic E. coli produced sharp contractions in every trial. A similar treatment with extracts of four non-hemolytic E. coli strains also stimulated the non-sensitized guinea-pig uterus but the magnitude of the contractions was much less. These studies indicated that the cell-free extracts of hemolytic E. coli produced a marked nonspecific toxic reaction.