Preliminary experiments on vaccination and serum treatment in the prophylaxis of E. coli O149:H10 infections in newborn piglets

In a preliminary experiment two sows were vaccinated, respectively a fortnight and seven weeks before expected farrowing, with a vaccine consisting of equal parts of a suspension of E. coli strain A₁ serotype O149:K91:H10 and Freund’s incomplete adjuvant, final concentration 5×10⁹ organisms/ml, dose 4 ml, administered subcutaneously behind the ear. The vaccine gave rise to an immediate local reaction and left a fibrous nodule of walnut-size, but no systemic reaction was noticed. This agrees with experience from experimental work with vaccination of cows (Dam 1968) with a vaccine of the same composition, but representing the calf-pathogenic types of E. coli, and with experiences from the widespread use of vaccine of the same strength, but with the complete Freund adjuvant, in the prophylaxis of bovine colibacillosis in Belgium (Schoenaers & Kaeckenbeeck 1963). In none of these studies were systemic reactions ever observed.