Evaluation of Different Diagnostic Approaches for Detection of Cryptosporidium in Stools of Diarrheic Children

Abstract

Background: Cryptosporidiosis is of utmost importance especially in vulnerable age groups in developing countries. Malnourished children are more susceptible to recurrent diarrheal episodes, which can lead to chronic nutritional and cognitive sequelae or even death. Objective(s): to evaluate four different diagnostic approaches for Cryptosporidium infection in stools of diarrheic children. Methods:One hundred stool specimens were collected from diarrheic children in Alexandria University Children Hospital (El-Shatby). All samples were investigated by four techniques; directly by microscopic detection of Cryptosporidium oocysts using modified Ziehl-Neelsen (MZN) stain. Indirectly, through detection of coproantigen by enzyme linked immunosorbent assay (ELISA) and rapid strip test. Cryptosporidium DNA was detected by conventional polymerase chain reaction (PCR). Results: Using the four methods, 65% of examined children had Cryptosporidium infection, while Cryptosporidium oocysts were shown by MZN stain technique among 41%. However, by rapid strip test, ELISA, and PCR the percentages were 45%, 48%, and 59%, respectively. PCR elicited the highest diagnostic efficiency (64%) among the three diagnostic non-microscopic techniques when the MZN technique was used as the gold standard test. However, rapid strip test showed the least diagnostic efficiency (48%) when compared to PCR that was considered as the gold standard test. Meanwhile, ELISA was of moderate performance when compared to either PCR or to MZN technique used as gold standard test. Conclusion: PCR was more sensitive than rapid strip test and ELISA. It is time saving, but not cost effective. The rapid strip test could be considered as a complementary (additional) tool rather than a substitute for microscopic examination. It could be used for screening in cases of outbreaks of diarrhea for faster management of the problem.

Performance of diagnostic assays used to detect Cryptosporidium oocysts in faecal samples of cattle in Kuwait and genotyping of Cryptosporidium species

“…In comparison to microscopy, ELISA, and PCR procedures, the rapid IC assay was quicker and simpler to do because it didn't call for any extra special equipment. This reaerch reported false-positive results with rapid IC tests consistent with previous studies [22,27]. The IC test had a PPV of 65.22%, indicating that positive results with this assay need to be confirmed microscopically or using PCR.…”

“…A previous study evaluated different diagnostic methods used to detect Cryptosporidium in stools of diarrheic children using PCR as a gold standard. mZN revealed higher specificity than ELISA and rapid strip, while ELISA showed the highest sensitivity [22]. In another study, using PCR as a gold standard to evaluate immunological tests for diagnosis of Cryptosporidium in diarrheic animals (pigs, calves, and lambs), ELISA (40.9%) showed higher sensitivity than IC (22.7%), while IC (100%) showed higher specificity than ELISA (78.9%) [19].…”

Detection of Cryptosporidium parvum in calf feces using microscopical, serological, and molecular methods

“…Fecal samples were diluted and incubated in the coated wells. After 1 h incubation at 21°C +/-3°C, tetramethylbenzidine was added, and the absorbance was read at 450 nm using a microplate ELISA reader (Thermo Scientific, USA) (18).…”