CRYPTO RESEARCH - ARE FUNDAMENTAL DATA MISSING

Noting the dearth of accurate information regarding the quality and qu antity of Cryptosporidium oocysts used for experimentation, the author s used isolates meeting stringent quality assurance criteria to docume nt the variation of results with three different enumeration technique s-hemacytometer, cellulose-acetate membrane, and well slide. In 70 com parisons of the three techniques, results generated by well slide and hemacytometer varied by an average of 24.7 percent, hemacytometer and membrane results varied 67.6 percent, and well-slide and membrane resu lts varied 79.3 percent. Significant discrepancies between counts gene rated by different techniques indicate a strong probability of poor ac curacy in previous enumeration-based studies. Recovery of oocysts afte r Percoll-sucrose flotation varied considerably with either hemacytome ter or membrane-counting techniques, which helps explain low precision with the Information Collection Rule protozoan method. Incomplete des cription of experimental procedures hinders Cryptosporidium research d irected toward improving the analytical method, evaluation of water tr eatment efficacy, and surrogate development.