Cryptosporidium parvum development in the BS-C-1 cell line.

Cryptosporidium parvum is a worldwide parasitic protozoon capable of causing life-threatening disease in immunocompromised patients. In vitro cultivation of C. parvum has been under investigation for development of a well-defined in vitro model for C. parvum infectivity assay. This is the first report of C. parvum completing its life cycle in BS-C-1, an African green monkey kidney cell line. Both sodium hypochlorite-stimulated oocysts and purified sporozoites were able to initiate infection that led to completion of the whole life cycle, although inoculating purified sporozoites was less efficient. Beside Giemsa staining and normal light microscopy, an indirect fluorescent antibody staining method was developed to facilitate the detection and interpretation of C. parvum life stages developed in vitro. A C. parvum-specific polymerase chain reaction was also applied to detect and confirm the presence of C. parvum life stages in liquid from oocyst-infected cell cultures. In addition to the 452-base-pair (bp) product that can be specifically amplified from C. parvum oocysts and sporozoites, a fragment near 280 bp was also obtained. Various applications of this in vitro culture system are envisioned.