Clinical and Microbiological Investigation of Zoonotic Cryptosporidiosis in two Children by Routine Diagnostic Methods and Quantitative Polymerase Chain Reaction - Abstract
To investigate the applicability of diagnostic assays for detection of the protozoan parasite Cryptosporidium parvum throughout the course of natural zoonotic infections, and to compare oocyst loads with clinical presentation, sequential stool samples from two naturally infected, volunteer siblings were tested by modified Ziehl-Neelsen (mZN), auramine phenol (AP), and immunofluorescence microscopy, enzyme immune assays (EIA) and quantitative PCR (qPCR). Cryptosporidium was detected by immunofluorescence microscopy, EIA and qPCR but not by mZN or AP in soft stools passed after acute clinical episodes of cryptosporidiosis. During recuperation, samples were positive only by IFM and qPCR of DNA extracted directly from stools; the latter provided the highest diagnostic index and intermittent detection up to 18 days after recovery from all symptoms. Additionally, quantification by qPCR correlated with symptom severity and clinical presentation in the two patients studied.