Rapidly measured indicators of recreational water quality and swimming-associated illness at marine beaches: a prospective cohort study

Table 5 GI illness by swimming status and presence of F+ coliphage by 24-hour SPOT Assay and 5-hour CLAT Assay

	Number ill	%	AOR²(95% CI)	AOR-trend³(95% CI)
F+ Coliphage Spot Assay ¹
Non-swimmer	87	4.90	ref
0.1, 0.7	39	6.74	1.52(0.98-2.36)
0.7, 24	64	8.47	1.699(1.12-2.57)	1.15(0.69-1.92)
F+ RNA Coliphage CLAT Assay
Non-swimmer	87	4.90	ref
Absent⁴	39	6.69	1.18(0.74-1.88)
Present⁴	64	8.51	1.8(1.22-2.66)	1.55(0.9-2.66)
F+ DNA Coliphage CLAT Assay
Non-swimmer	87	4.90	ref
Absent⁴	23	6.05	1.11(0.64-1.93)
Present⁴	80	8.38	1.69(1.16-2.47)	1.61(0.86-3)

1: Daily Geometric Mean, Plaque forming units per 100 ml estimated by Most Probable Number (MPN) Method
2: Adjusted Odds Ratio comparing exposed swimmers to non-swimming reference group
3: Adjusted Odds Ratio for a 1-log increase in coliphage on a continuous scale among swimmers
4: Swimmers exposed on days when coliphage absent or present by the CLAT assay

ISSN: 1476-069X