The utilization of sodium taurocholate in excystation of Cryptosporidium parvum and infection of tissue culture

The present work deals with optimization of excystation of Cryptosporidium parvum oocysts and the infection process of tissue culture cells by the par asite. It was shown that presence of the bile salt sodium taurocholate in t he incubation medium expedited excystation of the tested GCHl isolate and e nhanced it, as compared with bleaching of the oocysts. This bile salt had n o effect on the viability of tissue culture cell lines MDBK and HCT-8 at th e tested concentration of 0.375% for up to 2 hr of coincubation. Infection studies conducted on tissue culture cells showed higher infection rates in the presence of sodium taurocholate than with bleached oocysts in the absen ce of this bile salt. It may be. concluded that, at least as regards the GC H1 strain of C. parvum, the whole infection process can be performed in the presence of sodium taurocholate, and does not require separation and clean ing of the excysted sporozoites before their application to tissue culture cells.