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Cryptosporidiosis - Diagnosis
Last reviewed: 03.07.2025
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Laboratory diagnostics of cryptosporidiosis
Laboratory diagnostics of cryptosporidiosis do not reveal specific changes. Severe cryptosporidiosis develops with severe immunodeficiency (the number of CD4 lymphocytes is below 0.1x10 9 /l), therefore, changes characteristic of its manifestations (for example, leukopenia and erythrocytopenia) are recorded in the tests.
Methods for detecting cryptosporidium oocysts in feces have been developed. For this purpose, the Ziehl-Neelsen staining method, the Koester safranin staining method, and the Romanovsky-Giemsa azure-eosin staining method, as well as negative staining methods, are used. Flotation or sedimentation methods are used (if the material contains a small number of oocysts); when using appropriate preservatives, oocysts can be detected in native material stored in the refrigerator for 1 year.
Recently, monoclonal antibodies with a fluorescent label have been used, which allows visualizing the pathogen with high specificity and sensitivity. The reaction of fluorescent antibodies, ELISA and IB are used in epidemiological studies. It is possible to use molecular methods, in particular PCR.
Differential diagnosis of cryptosporidiosis
Differential diagnostics of cryptosporidiosis is carried out with diseases accompanied by diarrhea and dehydration, in particular with cholera (especially during outbreaks of the disease), amoebiasis, salmonellosis, shigellosis, campylobacteriosis, and in patients with HIV infection - with cytomegalovirus colitis, microsporidiosis, isosporiasis, and diseases of the biliary system.
Differential diagnosis of cryptosporidiosis and cholera
Signs |
Cryptosporidiosis |
Cholera |
Clinical signs |
Acute onset, severe diarrhea (frequent watery stools with a foul odor), development of dehydration within a few days Moderate spastic abdominal pain Body temperature no higher than 38 °C Nausea and vomiting in 50% of patients. Symptoms are relieved on their own (within 3-10 days) or quickly disappear with rehydration therapy. In patients in the late stages of HIV infection, chronic course leading to dehydration, exhaustion and death. In patients with involvement of the biliary system - signs of cholangitis, cholecystitis |
Acute onset, severe diarrhea (frequent stools in the form of rice water), rapid development of dehydration symptoms depending on the degree of dehydration up to algid. Abdominal pain is absent. Body temperature does not rise. Vomiting appears after diarrhea |
Laboratory indicators |
Signs of dehydration, metabolic acidosis: in case of damage to the biliary system - increased activity of ALT, AST, alkaline phosphatase. Cryptosporidium oocysts are found in feces. Low immune status indicators (the number of CD4 lymphocytes in HIV infection is below 0.1x10 9 l) |
The severity of metabolic acidosis depending on the degree of dehydration. The cholera vibrio is found in vomit and feces. |
Epidemiological history |
Link to waterborne outbreaks or occupational risk of late-stage HIV infection |
Staying in a cholera outbreak |
Differential diagnostics of cryptosporidiosis and cytomegalovirus colitis in patients with HIV infection
| Cryptosporidiosis | CMV colitis |
| Acute or subacute onset with diarrhea, gradual increase in stool frequency over several weeks to months, leading to chronic disease and development of slim syndrome. Body temperature can rise to 38 °C; in many patients, body temperature is normal. In patients with involvement of the biliary system, signs of cholangitis, cholecystitis, increased activity of ALT, AST, ALP | Gradual onset of the disease, prodromal period (increasing frequency of stool over several weeks and even months). At the height of the disease, the stool is liquid with a frequency of 5-10 times a day. Characterized by severe pain in the lower abdomen, tenderness on palpation. Sometimes symptoms of acute abdomen. Body temperature rises to 38.5-40 °C. Colonoscopy reveals erosions and ulcers (the colon is most often affected). High concentration of CMV DNA in the blood |
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