Table 2.

Level of E. coli O157:H7 isolates with different hypothesized risk factors from Haramaya University and Adele Poultry Farms.

Risk factors	Risk categories	Number examined	Number positive	Proportion (%)	OR (95% CI)	P value
Source	HUPFa	106	7	6.6	1
	APFb	88	19	21.6	3.89 (1.5–11.5)	0.002
Age	Adult	93	5	7.5	1
	Young	101	21	18.8	4.62 (1.6–16.3)	0.021
Breed	Feyumi	85	7	10.6	1
	White Leghorn	109	19	15.6	2.35 (0.9–6.9)	0.310
Total		194	26	13.4

^aHaramaya University Poultry Farm.

^bAdele Poultry Farm.