| mycobacterium avium subsp. paratuberculosis in lake catchments, in river water abstracted for domestic use, and in effluent from domestic sewage treatment works: diverse opportunities for environmental cycling and human exposure. | mycobacterium avium subsp. paratuberculosis from infected animals enters surface waters and rivers in runoff from contaminated pastures. we studied the river tywi in south wales, united kingdom, whose catchment comprises 1,100 km2 containing more than a million dairy and beef cattle and more than 1.3 million sheep. the river tywi is abstracted for the domestic water supply. between august 2002 and april 2003, 48 of 70 (68.8%) twice-weekly river water samples tested positive by is900 pcr. in rive ... | 2006 | 16751517 |