Passive immunoprophylaxis of edema disease in weaned piglets

Hyperimmune sera against Shiga toxin Stx2e with antibody titres 8 000-32 000, prepared by immunization of slaughter pigs, were administered subcutaneously to piglets (n = 73) 3 days after weaning. The titres of Stx2e neutralizing antibodies in sera of piglets ranged from 16 to 512 following application of the immune serum. In most of the piglets, passively acquired antibodies disappeared during 4 to 8 weeks after application. The recorded serum titres were in all of the piglets 8 or higher fourteen days following administration. In another experiment, an immune porcine serum with antibody titre against Stx2e of 130 000 was applied subcutaneously into a knee fold to 30 piglets. The serum was applied at the dose 3 ml, 1.5 ml, 0.75 ml, 0.4 ml, 0.2 ml, 0.1 ml, and 0.05 ml based on the group of piglets. Antibody-free serum was applied to pigs of the control group (n = 5). The following day, supernatant of STEC culture with Stx2e titre of 150 000 was applied to piglets of both experimental and control groups into the opposite knee fold that the above serum. Piglets that received 0.2 to 3 ml of serum remained unaffected throughout the experiment following application of supernatant containing Stx2e. Piglets that received 0.05 ml of serum and those of the control group showed severe clinical manifestations of edema disease following Stx2e application and were sacrificed ante finem. Marked signs of the disease could already be observed 18 hrs following Stx2e application. In a group of 3 piglets that received 0.1 ml of serum, mild paralysis was observed in 1 piglet 18 hrs following Stx2e application.