TABLE 1.

Impact of i.p. administration of Stx2 swine immune serum (4 ml/kg) given at three different intervals, on development of neurological complications in piglets challenged with 10¹⁰ organisms of strain 86-24

Treatment group	Time (h) after challenge	No. of pigs	No. with:
			Colonic lesions	CNS
				Signsa	Lesions
Placebo	6	6	6	5	5
Swine control serum	12	10	9	8b	8
Stx2 swine immune serum	6	8	8	0	0
	12	11	11	1	1d
	24	11	11	3	1
Control 1	NAe	5	5	0	0
Control 2	NA	4	0	0	0

^aTwo groups were given the same dose of either swine control serum from an unimmunized animal or PBS (placebo). An untreated control group (control 1) challenged with the Stx2 deletion mutant strain TUV86-2 (12) was included to illustrate the role of Stx2 in CNS involvement. A second control group (control 2) received neither challenge nor treatment. 

^bAll piglets except those in the swine control serum were euthanized when recumbent before death. 

^cMild symptoms of ataxia but no neurological lesions were observed in one piglet. 

^dMild characteristic neurological lesions were observed in one of the asymptomatic animals. 

^eNA, not applicable.