AWWA WQTC55195

The recoveries of Cryptosporidium using Method 1623 in 50 L of reagent water and PE samples were 60% and 62%, respectively with 11% RSD. In 10 L of matrix spikes, the mean recovery was 42% with 13% RSD. The results indicate that Filta-Max filter gave sufficient recovery from different matrices with a low RSD. To faciliate the sampling process in the field, a simple, convenient, and fast sampling apparatus was constructed and tested. Of 19 surface water samples, 7 were positive for Cryptosporidium by Method 1623 with a range of 1 to 10 oocysts per 10 L. Among these 7 positive samples, 5 were also positive for Cryptosporidium by PCR. C. parvum bovine strain were identified by the RFLP in 4 of these surface water samples. One sample contained both C. parvum bovine strain and C. muris. All 12 samples negative by Method 1623 were negative by PCR. The results demonstrated a high degree of agreement (95%) between the two methods. The results prove it is feasible to use single filter (Filta-Max) to detect the presence of Cryptosporidium, confirm that presence, quantify the numbers of oocysts, and identify the species of Cryptosporidium present in surface water samples. Includes 5 references, tables, figures.