These findings imply that isolation of adult patients with Cryptosporidium diarrhea is not required to prevent Cryptosporidium transmission from roommate to roommate. Isolation should be considered for children and adults who are at increased risk for developing serious complications from Cryptosporidium infection, such as those who are immunocompromised. Patients do not need to remain in isolation after recovery from Cryptosporidium infection. However, if another patient becomes ill with similar symptoms, it is important to avoid contact with stool until test results are known because it may signal the presence of infectious Cryptosporidium particles. Contact with stool can also lead to transmission through fomites (non-living objects such as linen or equipment that have been contaminated with stool). Isolation is also recommended for individuals who provide care for a person with suspected or confirmed Cryptosporidium infection. This includes anyone who cares for an infant, child, pregnant woman, or immunocompromised individual. Caregivers should use caution not to contaminate their hands when interacting with infants or small children who may not be able to tell them they have been exposed to stool. Hand washing after contact with a patient's stools reduces the chance of spreading the infection.