Since its discovery in the early 20th century, Apicomplexan parasites, notably Cryptosporidium, have been neglected despite their significant impact on human and animal health.

A key unresolved question is the particular vulnerability of children, globally and in New Zealand, to cryptosporidiosis, a disease that can cause developmental and cognitive delays, especially in malnourished children.

Cryptosporidium parvum, the predominant species causing cryptosporidiosis, can infect a broad spectrum of hosts, including mammals, birds, and some fish. In developed countries like New Zealand, livestock are the main reservoirs for C. parvum, with cryptosporidiosis cases peaking during calving and lambing seasons. Currently, there are no vaccines or effective treatments for cryptosporidiosis, which can cause acute, sometimes fatal, gastroenteritis in neonates and immunocompromised hosts.

One of the challenges in developing new therapeutics is the absence of a continuous in vitro model for Cryptosporidium, leading to gaps in our understanding of its lifecycle, especially the regulation of its alternating asexual and sexual phases and oocyst formation. Our laboratory's main goal has been to develop a high-throughput in vitro culturing platform for Cryptosporidium spp., to screen novel therapeutics. This seminar presents our methods for testing compounds against asexual and sexual stages of the parasite, utilizing qPCR and fluorescent microscopy for detection and analyzing specific gene expression.

We examine the effects of new and existing anti-cryptosporidial compounds on stages like parasitic invasion, DNA replication, merozoite egress, including their impact on sexual gene switching and specific male and female gametes. Additionally, we explore the difficulties in creating a continuous in vitro model for Cryptosporidium, both axenic and host-cell-based, using COLO-680N cells and hollow-fiber technology.

Establishing a reliable continuous in vitro model is challenging but crucial for advancing the development of sensitive diagnostics, effective therapeutics, and disinfectants targeting the highly infectious oocysts of this important parasitic disease.

This work could significantly impact public health by providing new tools to combat a parasite that affects a vulnerable population segment and has a considerable economic impact due to its prevalence in livestock.