ABSTRACT
This chapter deals with Cryptosporidium diagnosis in clinical samples from infected human and nonhuman hosts. Cryptosporidium parvum and C. andersoni have been associated with morbidity in livestock, whereas C. baileyi, C. galli, and C. meleagridis have been associated with morbidity in domesticated fowl. The diagnostic difficulty arises when microscopy is employed and oocysts cannot be distinguished morphologically at the species level. Methods to concentrate oocysts from feces while reducing debris increase the sensitivity of diagnostic methods. The most common concentration methods include Sheather’s sucrose flotation method and formol-ether concentration. When stool samples are to be processed as direct smears, specialized parasitology diagnostic and reference laboratories might be requested to investigate a sample for the presence of a variety of parasitic enteropathogens, including Cryptosporidium. For polymerase chain reaction (PCR)-based methods, nested PCR methods, being more sensitive than direct PCR methods, are likely to have a higher diagnostic index.
