Cattle are infected with two species of C. parvum, which colonizes the small intestine of young claves and C. andersoni presents in the abomasum of cattle greater than 5 months of age.
The parasite was linked with diarrheal disease in variety of animal species and eventually in 1976, two humans cases were described, one in an immuno-competent child and the other in an immuno-suppressed adult.
C. parvum is zoonotic, apparently lacking host specificity among mammals. Opportunities for such infection increase with close human-to-human contact and during care of infected livestock, zoo animals and companion animals. Contracting C. parvum by drinking contaminated water was recognized from earlier reports human infections.
Cryptosporidium parvum
