Introduction Cryptosporidium parvum is a leading pathogen that causes diarrhea in young children and immunocompromised patients. In 1976 Cryptosporidium (crypto) the protozoan waterborne parasite was first acknowledged as a diarrhea agent (Navin). Severe infection by crypto causes damage to the small intestine epithelium(), this blocks important processes in the small intestine and causes mild-to-severe diarrhea (). Crypto is an important pathogen that upon infection causes morbidity and mortality in malnourished children and children with AIDS(). In young children who are infected diarrhea is severe and can lead to complications or even death. However, in adults diarrhea typically last for several weeks but usually self-cures itself. This parasite can gets transmitted via oral-fecal route.Due to the size of the oocyst it is hard to detect when water is contaminated. Another disadvantage is that the oocysts are resistant to chlorinated water. It only takes one gulp of contaminated water for individuals that come in contact with it suffer infection. This parasite is zoonotic and can infect not just humans but it also infects calves. Its main host is calves at the age of 7-12 days, infection by crypto causes severe diarrhea. Which is why this parasite is a prominent veterinary pathogen. The route of infection for calves is the same as human through oral uptake. This is because that oocysts shed into the feces and contaminate the environment around the cattle. Locations where there are calves the likelihood of infection by crypto rises. It is recommended by the CDC that if there is any contact with animals, children and adults should wash their hands. It is important to take precautions when visiting aquatic centers. If children or adults have diarrhea or recently had diarrhea it is recommended to stay out of the water to prevent any contamination. Outbreaks of crypto normally occur during the summer in aquatic centers such as pools or in areas were there are farms. Cryptosporidium life cycle Sporulated oocysts get released in the feces of the calves or humans. These oocysts are thick-walled and contain four sporosites inside. The sporosites inside the oocyst are highly infectious once they excyst from the oocyst. The excystation of the sporozoites happens once an individual is infected and the oocyst has made its way to the small intestine. The sporozoites forms a trophozoite that starts to propagate and leads to the formation of meronts that contain six to eight merozoites inside (Figure 1). When these merozoites get release they begin to invade other enterocytes. The merozoites II are form gametocytes as the invasion of the enterocytes progresses. Once the macrogamonts get fertilized two different oocysts are produced, a thick-walled and thin-walled oocyst. The thick-walled oocysts are shed into the feces and the thin-walled are thought to auto-infection. Figure 1: The life cycle of Cryptosporidium parvum upon infection. Limitation in crypto research Research on crypto has faced limitations that have been it difficult to fully study the parasite. Although there are in vitro methods to study this parasite, timewise there is a small time period in which the parasite can be study in vitro. One way is the parasite can be studied in cell culture however the parasite can not be passage continous in cell culture (). The parasite can be passage and observe for 2-3 days in cell culture using human ileocaecal adenocarcinoma cells (HCT-8) (). Genetic tools in crypto research With the use of genetics and molecular biology new tools have been developed to facilitate the study of crypto. Figure 2: The pipeline for the propagation of transgenic oocyst. Drug efficacy