Volume 14, Number 1—January 2008
Cryptosporidiosis and Filtration of Water from Loch Lomond, Scotland
|Relation to enhanced water filtration†||Water source, no. (%)*
|Before||341 (222)||727 (846)||1,068|
|After||171 (290)||1,227 (1,108)||1,398|
*Numbers in parentheses are cases expected under the null hypothesis (i.e., no association between water supply and filtration).
†Coagulation and rapid gravity filtration, introduced in November 1999.