TABLE 4.

Radiometric culture of soil and pasture samples inoculated with ovine feces containing M. paratuberculosis^a

Sample	Level of M. paratuberculosis in feces	Dilution of feces in sample	Time to positive PCR result (wk)	GI when the culture was PCR positive
Soil	High	1:10	2b	58
	High	1:100	5	11
	High	1:1,000	5c	778
	Low	1:10	3b	434
	Low	1:100	6c	899
	Low	1:1,000	4	10
Pasture	High	1:10	4c	999
	High	1:100	4	373
	High	1:1,000	4	18
	Low	1:10	4c	612
	Low	1:100	4	11
	Low	1:1,000	4	14

^aIS900 PCR was used to identify M. paratuberculosis. Cultures were incubated for 6 weeks. 

^bThe sample collected from culture in week 6 was PCR positive only after ethanol and silica preparation. 

^cThe samples from culture were PCR negative when they were first tested but were PCR positive in all later weeks.