Cryptosporidiosis: A parasitic intestinal disease. Cryptosporidiosis is an intestinal disease affecting both humans and many animals. It is caused by the singled celled, eukaryotic parasite Cryptosporidium parvum. While most healthy adults are able to recover from the disease without treatment within weeks, immunocompromised and malnourished patients may suffer severe complications and death. Effective treatment for cryptosporidiosis and prevention against infection with C. parvum do not exist. [Umejiego et al., 2008]
Purine salvage enzyme may be C. parvum drug target. One discovery in 2004 showed that the enzyme inosine-5-monophosphate dehydrogenase (IMPDH) is required to synthesize guanine nucleotides in C. parvum. Gene sequence analysis of IMPDH revealed that the C. parvum enzyme is highly similar to bacterial IMPDH, but is quite divergent from human IMPDH.The discovery of this difference between human and C. parvum metabolism presented an attractive potential for development of drugs to target the parasite enzyme without affecting the human host. [Striepen et al., 2004].
Test compounds may treat infection. Umejiego et al. (2008) identified four compounds that effectively inhibited binding of NAD+ to the NAD+ active site of C. parvum IMPDH. Parasite growth was reduced, but human IMPDH was not affected and there was low toxicity to human cells. Further research on these and related compounds could lead to the first effective treatments for cryptosporidiosis. [Umejiego et al., 2008]