Cryptosporidium hatching: unzipping the suture at the perfect time

Cryptosporidium is a waterborne pathogen that is transmitted inside a microscopic shell-like structure called an oocyst. This shell protects Cryptosporidium parasites from most water treatments, including chlorination. Once ingested, parasites “hatch” from the oocyst and infect the intestine, causing diarrhoeal disease. The impact of cryptosporidiosis is second only to Rotavirus. Annually there are an estimated 7.5 million cases of cryptosporidiosis in Africa and Asia, resulting in excess of 200,000 deaths and 8.2 million disability adjusted life years. There is currently no vaccine and no effective treatment for cryptosporidiosis. Hatching out of their eggshell is a critical bottleneck in parasite transmission. New tools we created allow us to investigate the biology of hatching and open this area for exploration. We recently identified proteins that are located at the zipper-like opening on the oocyst shell. We will use genetics, biochemistry, and microscopy to understand how Cryptosporidium build the protective shell and zipper opening, and hatch at the perfect time. Using microscopic biomechanical techniques will understand why oocysts are so resilient. These insights have the potential to help us understand how to interrupt infection and stop parasite transmission.