Comparison of three methods (Microscopy, immunochromatography and Real-time PCR technique for the detection of Giardia lamblia and Cryptosporidiu parvum

Giardiasis and Cryptosporidiosis are a significant health problem in countries with poor sanitation and unsafe water, human are infected by feco-oral route either directly or indirectly and in all age groups. Microscopical, immunochromatography and molecular assay are the most important methods for detection. To compare of direct microscopic examination with immunochromatograic test and real-time PCR assay for the detection of Giardia lamblia and Cryptosporidium parvum. We studied 180 children (93) females and (87) males, aged from 5 -15 years, who attended the out patients clinical of the Central Teaching Hospital for Pediatric in Baghdad city, during the period from June 2014 to October 2014, with gastrointestinal complaints. All specimens examined by light microscopy. Parasitic infection also examined by one step colored chromatographic immunoassay and real-time PCR technique. Out of one hundred eighty stool specimens, 95 had positive results of parasitic-infection while 85 with negative result. Most parasitic infection recorded in age group 5-10 years and in males, based on lab diagnosis 40% (38/95) of stool specimens were positive for Giardia lamblia and 4.21% (4/95) were positive for Cryptosporidium parvum microscopically, 40% (38/95) and 7.36% (7/95) of the stool specimens were found to be positive for Giardia lamblia and Cryptosporidium parvum respectively by immunochromatography assay. According to RT-PCR 47.36% (45/95) was positive for Giardia lamblia while 7.36% (7/95) was positive for Cryptosporidium parvum. Sensitivity and specificity of PCR was 100% compared to sensitivity of microscopy and immunochromatography assay. Microscopy exhibited many false positive and negative cases with two parasites. More sensitive and specific method for the detection of intestinal protozoa is molecular technique. It also offers the opportunity of familiarizing DNA detection in many laboratories and should be considered the gold standard methods for the diagnosis of parasitic disease.