Disease caused by the Apicomplexan protozoan parasite Cryptosporidium.
Laboratory diagnosis is required, usually by detection of oocysts, antigens, or DNA in stool samples.
Presents as watery diarrhea, often with severe abdominal pain, commonly lasting >7 days.
The disease is self-limited in immunocompetent patients.
Patients who are severely immunocompromised may suffer chronic, severe, and intractable disease. Most at risk are those with T-cell immune deficiencies, notably advanced HIV infection, or primary T-cell immune deficiencies, and those with hematologic malignancies, particularly children.
Nitazoxanide may be used for treatment of cryptosporidiosis in immunocompetent people >1 year of age.
Cryptosporidium has caused outbreaks associated with, for example, contaminated drinking water supplies, food (especially fresh produce), swimming pools, children's day care facilities, and petting farms.
Cryptosporidiosis is illness caused by the protozoan parasite Cryptosporidium, characterized by watery diarrhea and often accompanied by abdominal cramps, loss of appetite, low-grade fever, nausea, and/or vomiting. Symptoms, which usually last for up to 2 weeks and sometimes up to 4 weeks, may relapse after initial resolution. Cryptosporidium can cause prolonged, severe disease that may be life-threatening in some groups of severely immunocompromised patients.
History and exam
Key diagnostic factors
Other diagnostic factors
- abdominal pain
- loss of appetite
- low-grade fever
- loss of weight
- right upper quadrant abdominal pain
- nasal discharge and facial pain
- cough and dyspnea
- contact with farm animals, especially calves and lambs
- international travel
- age: 3 years or younger
- immune deficiency: T-cell-mediated
- swimming and recreational water sports
- drinking unfiltered water
- toileting or changing diapers of young children
1st investigations to order
- stool microscopy
- Cryptosporidium antigen detection
Investigations to consider
- ultrasound scan of the biliary tract
- CT scan of the biliary tract
- endoscopic retrograde cholangiopancreatography (ERCP)
- polymerase chain reaction for Cryptosporidium DNA
- polymerase chain reaction for Cryptosporidium species identification
- Acute diarrhea
- Chronic diarrhea
- Crohn disease
- Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents
- Guidelines for the prevention and treatment of opportunistic infections in HIV-exposed and HIV-infected children
Diarrhea in adults
Diarrhea in childrenMore Patient leaflets
- Log in or subscribe to access all of BMJ Best Practice
Use of this content is subject to our disclaimer