TABLE 2.

Incidence of Highly Credible Gastroenteritis (HCG) in Active and Sham Water Treatment Groups: Adelaide and Mount Barker, Australia, 2007–2008

	All participants		Children Aged ≤ 5 Years
No. of HCG Events	Active Group (n = 638), No. Persons (%)	Sham Group (n = 609), No. Persons (%)	Active Group (n = 81), No. Persons (%)	Sham Group (n = 90), No. Persons (%)
0	372 (58.3)	374 (61.4)	25 (30.9)	31 (34.4)
1–2	232 (36.4)	206 (33.8)	46 (56.8)	48 (53.3)
3–4	27 (4.2)	26 (4.3)	8 (9.9)	8 (8.9)
5–7	7 (1.1)	3 (0.5)	2 (2.5)	3 (3.3)

Note. HCG was defined as any of the following in a 24-hour period: 2 or more loose stools; 2 or more episodes of vomiting; 1 loose stool together with abdominal pain, nausea, or vomiting; 1 episode of vomiting with abdominal pain or nausea. The active group received water treatment units containing filters for their rainwater. The sham group received water treatment units that were identical to the active units, except that they did not contain filters. Investigators and participants were blinded to the identity of the active and sham households.