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 diarrhoea, often with severe abdominal pain, commonly lasting >7 days.
The disease is self-limiting 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 haematological 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, characterised by watery diarrhoea 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
- presence of risk 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 dyspnoea
- 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 nappies 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
Rachel M. Chalmers, BSc, PhD
Consultant Clinical Scientist/Honorary Professor
Director of UK Cryptosporidium Reference Unit
Public Health Wales Microbiology
RMC is a member of the following boards: WHO Water Quality and Health Technical Advisory Group; the UK Standards for Microbiology Investigations Bacteriology Working Group; Public Health England Water Advisory Group and Gastro-Intestinal Leads Group; Wales Microbiology Standing Specialist Advisory Group. RMC has received grant funding from EU FP7 project 'Aquavalens' and EFSA partnering grant project IMPACT and has undertaken contract research from UK Water Industry Research. RMC has received payments for lectures and reimbursement for conference travel and subsistence. RMC is an author of a number of references cited in this topic.
Angharad P. Davies, MA, MBBCh, MRCP, FRCPath, PhD
Clinical Associate Professor
College of Medicine
APD is an author of a number of references cited in this topic.
Beth Kirkpatrick, MD
University of Vermont College of Medicine
BK declares that she has no competing interests.
Yann Meunier, MD
Stanford Health Promotion Network
Stanford School of Medicine
YM declares that he has no competing interests.
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