TABLE 2.

Characteristics of participating, noninfected, and nonparticipating household members in the 39 families with H. pylori cultures from two or more family members

Relationship	No. of participantsa	No. seronegativeb	Nonparticipants		Total no. of household members
			No. seropositiveb	No. with unknown serostatusc
Mother	35	1	4	0	40
Father	25	2	3	3	33
Offspring	44	29	47	8	128
Total	104	32	54	11	201

^aH. pylori-seropositive individuals who contributed bacterial isolates.

^bH. pylori serostatus was determined with an in-house enzyme-linked immunosorbent assay and immunoblot.

^cNo blood samples were available.