The most common method of diagnosing Cryptosporidiosis is acid-fast staining methods, with or without a stool sample. Acid-fast staining, or the Ziehl-Neelsen stain, is used to detect acid-fast mycobacteria. Because Cryptosporidium is acid-fast, it retains a red color as depicted in the picture below:


This photo is described by the CDC as, "Using a modified cold Kinyoun acid-fast staining technique, and under an oil immersion lens the Cryptosporidium sp. oocysts, which are acid-fast stain red, and the yeast cells, which are not acid-fast stain green."

The stool sample, on the other hand, may be more difficult to attain and several samples over several days may be needed to get accurate results and diagnosis. The CDC also suggests immunofluorescence microscopy, followed by enzyme immunoassays and distinguishes molecular methods as research tools. However, there are no commercially available serologic assays that detect Cryptosporidium-specific antibodies.2

The official 5 laboratory-confirmed signs of the presence of Cryptosporidium, as defined by the CDC's 1998 case definition is as follows:

  1. oocysts in stool by microscopic examination, or
  2. in intestinal fluid or small-bowel biopsy specimens, or
  3. oocyst or sporozoite antigens by immunodiagnostic methods, e.g., ELISA, or
  4. by PCR techniques when routinely available, or
  5. demonstration of reproductive stages in tissue preparations.



There is a new drug out on the market called nitazoxanide that is useful in patients with normal immune systems. The benefit of this drug for patients who are immunocompromised, for example AIDS patients, has not yet been tested. Also, because Crypto leads to excessive water loss, it is very important to intake lots of non-contaminated liquids and electrolytes. Common anti-diarrheal medications are also effective in relieving the diarrhea caused by Cryptosporidium. Anti-retroviral therapy that improves immune status has shown to decrease or eliminate symptoms of Crypto in AIDS patients; however, even if symptoms disappear, cryptosporidiosis is usually not curable and the symptoms may return if the immune status worsens. It is important to keep in mind that if you believe you may have Cryptosporidiosis, you should visit a physician immediately and do not self-medicate.4