title: Assessment of the conventional detection of fecal Cryptosporidium serpentis oocysts in subclinically infected captive snakes.
abstract: Fecal specimens of seven captive snakes naturally subclinically infected with Cryptosporidium serpentis were monitored for 131 days for the presence and concentration of oocysts. Thirty-three of 81 (41%) of the monoclonal antibody positive stools were read as negative (sensitivity 59%) by the acid-fast-stained (AFS) fecal smears. Oocyst concentrations in the false-negative stools ranged between 6.0 x 10(3)/g to 2.5 x 10(4)/g. The experimentally determined concentration-threshold of oocyst detection by AFS fecal smear was 3.0 x 10(4)/g. The stool weights did not conform to a normal distribution; the oocyst concentration was significantly correlated with the stool weight (P < 0.01). Due to this correlation, stools which constituted less than 0.41% of the snake weight were classified as negative by the AFS fecal smears. The AFS fecal smear technique should be used exclusively for the determination of Cryptosporidium-positive snakes, but not for diagnosis of snake negativity for Cryptosporidium; it should be applied only for larger fecal specimens, such as those which constitute more than 0.41% of snake weight. At least five to seven stool samples should be examined by fecal smear in order to determine snake positivity for Cryptosporidium in subclinical infection.
authors.affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: T K
authors.initials: TK
authors.lastname: Graczyk
authors.forename: M R
authors.initials: MR
authors.lastname: Cranfield
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D000911:Antibodies, Monoclonal; D003457:Cryptosporidiosis / Q000175:diagnosis / Q000662:veterinary*; D003458:Cryptosporidium / Q000302:isolation & purification*; D003951:Diagnostic Errors; D005188:False Negative Reactions; D005243:Feces / Q000469:parasitology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012911:Snakes / Q000469:parasitology*; D013045:Species Specificity; D013194:Staining and Labeling / Q000379:methods
chemical_list: D000911:Antibodies, Monoclonal