Cultivation of Cryptosporidium in host free cells culture using Iraqi isolate

Cryptosporidiosis is a clinical disease, usually presenting as a gastro-enteritis-like syndrome, caused by infection with protozoan parasites of the Apicomplexan genus Cryptosporidium. Disease ranges in seriousness from mild to severe and signs and symptoms depend on the site of infection and nutritional and immune status of the host Cryptosporidium in vitro was first achieved in endodermal cells of the chorioallantoic membrane (CAM) of chicken embryos (Current and Long, 1983). Numerous subsequent reports of the cultivation of the parasite in different cell lines followed; with varying degrees of success in terms of the development of Cryptosporidium life cycle stages (Hijjawi, 2003). Although major improvements in culturing Cryptosporidium in vitro has occurred in recent years, continuous culture and efficient life cycle completion (oocyst production) have only recently been achieved in vitro, with long term maintenance of the life cycle of three species of Cryptosporidium (C. parvum, C. hominis and Cryptosporidium andersoni) now possible (Hijjawi et al. 2001; Hijjawi, 2003). It is well recognized that successful Cryptosporidium cell culture systems have aided many aspects of Cryptosporidium research. Cryptosporidium in vitro culture has allowed the screening of antimicrobial compounds, enhanced studies on the developmental biology and life cycle of the parasite as well as supporting the needs of the water industry in terms of detection and viability screening. In the present study, we report the cultivation of C. parvum in a host cell-free system. This system is much easier to manage than previous culturing systems that required the presence of different host cell lines and overcomes the problems of overgrowth and aging of host cells, which prevent perpetuation of the Cryptosporidium life cycle in vitro. Furthermore, a host cell-free Cryptosporidium culture system will assist in future vaccine development against cryptosporidiosis, especially in terms of harvesting parasite stages free of host contamination, and simplify drug-screening protocols (Keegan et al. 2003).