Prevalence of cryptosporidiosis in symptomatic immunocompetent children and comparative evaluation of its diagnosis by Ziehl–Neelsen staining and antigen detection techniques

BACKGROUND: Cryptosporidia is a major pathogen causing diarrhoea and with increasing morbidity and mortality. As persistent diarrhoea from intestinal cryptosporidiosis leads to increased susceptibility to recurrent diarrheal episodes further leading to chronic nutritional and cognitive sequelae or even death, diagnosis is important. Most of the studies done on Cryptosporidium worldwide have focused on immunocompromised patients which have led to a paucity of data on its prevalence among immunocompetent people. AIMS AND OBJECTIVES: Keeping these facts in mind the present study was aimed to estimate prevalence of cryptosporidiosis in immunocompetent children, and do a comparative evaluation of its detection by microscopy with antigen detection methods. MATERIAL AND METHODS: 80 immunocompetent children (40 OPD children presenting with diarrhea and 40 children hospitalized for diarrhea) upto age of 5 years were studies and their stool samples were compared by microscopy by mZN with copro-antigen detection methods (using rapid ICT and ELISA) for the diagnosis of Cryptosporidiosis. RESULTS: A Cryptosporidium prevalence rate of 22.5% was detected in the immunocompetent children upto 5 years of age. Microscopy remained the preferred method of diagnosis for Cryptosporidium being a more sensitive test and considering it's low cost in resource poor settings. Moderate agreement between mZN and ELISA in Cohen's kappa test shows that either of the tests can be used for diagnosis of Cryptosporidium from fecal sample. ELISA is time-saving method but ELISA and rapid antigen tests should not be used as the sole method of diagnosis. Keeping in view the ICT kit used in this study is species specific, and the species identification was not carried out in the present study, hence genus specific kits may be useful for diagnosis in such settings. CONCLUSION: Microscopy remains the preferred method of diagnosis for Cryptosporidium having good sensitivity and specificity and considering it's low cost in resource poor settings. ELISA is time-saving method but ELISA and rapid antigen tests should not be used as the sole method of diagnosis.