Discussion

Cryptosporidium is a water-borne pathogen, which poses a major threat to animal health and welfare, and to public health, because there is no proper treatment and no immediate prospect of vaccine development. The increasing attention has focussed substantially more funding to develop drugs to eliminate Cryptosporidium as a human pathogen. Lack of proper in vitro culture system for Cryptosporidium maintenance and oocyst production means that recent increase in funding will dramatically increase animal use in this research field. A promising new method of rearing Cryptosporidium in the hollow fibre system (Morada et al. 2016) claims to generate up to 10⁸ Cryptosporidium oocysts per day. If this can be adapted into a routine methodology, the output of oocysts would meet the needs of the research community without using calves or other live animals. We are aiming at establishing the method at Cardiff University, and then making this supply available to other European Cryptosporidium laboratories. Before the technique can be adopted as the method of choice for Cryptosporidium oocyst supply, it is imperative that we (a) demonstrate the reliability of the method for the growth of different Cryptosporidium species and variants, including the human-infecting forms, and (b) assure the genetic stability of parasites grown in this system for many generations, relative to parasites reared in calves. The technology can be used by basic scientists; parasitologists, microbiologists, biochemists, pharmacologists and geneticists interested in cell-cycle control and the search for drugs against Cryptosporidium, and it will surely benefit veterinarians, medical practitioners and water treatment companies.