Sporozoites of Cryptosporidium parvum excysted in vitro from bovine oo
cysts were incubated with monolayers of Madin-Darby bovine kidney cell
s. The extent of parasite colonisation was monitored by light microsco
py and immunofluorescence. Electron microscopy confirmed the complete
development and replication of C. parvum within Madin-Darby bovine kid
ney cells.