[Preparation and testing of polyvalent EDTA-Na-extract vaccine from Escherichia coli strains pathogenic to Swine]. / Herstellung und Prüfung eines polyvalenten EDTA-Na-Extraktimpfstoffes aus schweinepathogenen Escherichia-coli-Stämmen.

Monovalent vaccines were prepared of E. coli strains with pathogenicity to swine by means of a technique described elsewhere. A polyvalent vaccine was obtained by mixing the monovalent vaccines. This polyvalent vaccine was tested by criteria usually applied to vaccine of E. coli strains with pathogenicity to man, and it exhibited the same quality characteristics.

[Laboratory experiments with a polyvalent extract vaccine for oral immunization against E. coli enteritis]. / Laboratoriumsversuche mit einem polyvalenten Extraktimpfstoff zur Oralimmunisierung gegen Enteritiscoli-Infektionen.

Bacteria of E. coli causing enteritis can be extracted by EDTA-sodium. These extracts having lower dry weights result in better protective effects in contrast to sodium-deoxycholate extracts. The EDTA-sodium extracts can be concentrated, purified and sterile filtrated. Thus the production of polyvalent vaccines is possible. A direct relation exists between the effectiveness of the extracts and the virulence of the strains used for extraction. The more virulent the original strain the better is the protective effect of the vaccine produced by extraction of the original strain. The single components of the polyvalent vaccine show a certain improvement of their protective effects. For estimating the immunizing dose, it is necessary to consider the limiting dose. When exceeding this dose the protective effect or the vaccine does not further increase but remains constant of even decreases. The immunizing dose wanted must be greater than the ED50 but smaller than the limiting dose. Extremely high oral doses of vaccine result in symptoms of incompatibility in mice.

[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)]. / Die Schutzwirkung von EDTA-Na-Extraktimpfstoffen aus schweinepathogenen E. coli-Bakterien in Feldversuchen. 1. Mitteilung: Direkte und indirekte Immunisierung von Saugferkeln.

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 Wroclaw. 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.

[The protective effect of an EDTA-sodium-extract-vaccine obtained from swine-pathogenic E. coli in a field trial. 2. Communication: Immunization of weanling piglets (author's transl)]. / Die Schutzwirkung von EDTA-Na-Extraktimpfstoffen aus schweinepathogenen E. coli-Bakterien im Feldversuch. 2. Mitteilung: Immunisierung von Absatzferkeln.

Pentavalent EDTA-Sodium-extract vaccines and monovalent EDTA-Sodium-extract vaccines obtained from swine-pathogenic E. coli were used to test their antiepizootic effect in industrial pig farms, 2929 piglets after weaning were included in this field trial, 1309 were immunized partly orally, partly i.m., 1620 piglets received placebos accordingly. By means of oral immunization the pentavalent vaccine was capable of reducing the morbidity of the vaccinated animals significantly. Intramuscular immunization with the pentavalent vaccines produced significant differences in morbidity too. A monovalent vaccine obtained from E. coli O149 and E. coli O8 was shown to be equally effective, whereas a monovalent vaccine obtained from E. coli O115 was ineffective. But in this stock there were infections with O149 but none with O115 or O8.

[Preliminary results of an atiepizootic field test using EDTA-Na extract vaccine from Escherichia coli strains pathogenic to swine in swine production industrial units]. / Erste Ergebnisse eines antiepizootischen Feldversuches mit einem EDTA-Na-Extraktimpfstoff aus schweinepathogenen Escherichia-coli-Stämmen in Anlagen der industriemässigen Schweineproduktion.

An anti-epizootic field test was applied to industrialised pig farms in the region of Wroclaw, Poland, to test the effectiveness of a pentavalent EDTA (calcium disodium edetate)--sodium vaccine extracted from Escherichia coli strains with pathogenicity to swine. The vaccine had been received from a centre in Berlin-Buch, GDR. The vaccine failed to provide any protection, when orally applied to nursed piglets. However, both morbidity and mortality were reduced and, thus, an anti-epizootic effect on nursed piglets produced, when the vaccine had been injected intramuscularly to the pregnant mother animals, prior to farrowing. In weaned piglets morbidity was sucessfully reduced by both oral as well as intramuscular administration.