[The protective effect of an EDTA-sodium-extract-vaccine obtained from swine-pathogenic E. coli in a field trial. 1. Communication: Direct and indirect immunization of suckling piglets (author's transl)].

Pentavalent EDTA-Sodium-extract-vaccines and monovalent EDTA-Sodium-extract-vaccines obtained from swine-pathogenic E. coli and produced in Berlin-Buch were used in field trials to test their antiepizootic effect in industrial pig-farms in the district of Wrocław. The pentavalent vaccine contained extracts from E. coli O138, O139, O141, O147, and O149, whereas extracts from O8, O115 and O149 were used as monovalent vaccines. The field trials were conducted as blind trials is closed stocks of pigs. We employed direct oral immunization of suckling piglets and indirect immunization via sow vaccination. Direct oral immunization was tested in 382 suckling piglets. 190 animals were vaccinated, 192 animals received placebo. Neither the pentavalent vaccine nor a monovalent vaccine obtained from an epizootie strain of this stock gave protection in terms of a decrease in the duration of disease or a reduction of morbidity and mortality. Direct oral-immunization of suckling piglets thus was ineffective. Indirect immunization of the suckling piglets via vaccination of sow was performed in 189 pregnant sows 18--15 days before farrowing. 84 sows received vaccines i.m., 105 were given placebo i.m. These sows farrowed 1717 pigs, 777 of which were immunized indirectly and 940 treated with placebos. With the pentavalent vaccine and with the monovalent vaccine obtained from an epizootic strain we achieved significant protection of the indirect vaccinated suckling piglets.