A most-probable-number assay for enumeration of infectious Cryptosporidium parvum oocysts

Research was conducted to quantify infectious Cryptosporidium parvum oocysts using the most-probable-number (MPN) method of enumerating microorganisms. The approach involved creating a dilution series, incubating the samples for an adequate period, plating in replicate and scoring the presence of growth. Results provide evidence that the focus detection method-MPN approach is an excellent and reproducible assay for quantifying oocyst infectivity in vitro.