EJMS

Abstract

Giardiasis is an illness caused by Giardia lamblia, a protozoan which inhabits the intestine of humans and other mammals. Many methods were used to diagnose it such as microscopy which is still being a reference test. However, due to the misdiagnosis caused by the intermittent release of the parasite in feces, other diagnostic methods should be searched for to overcome the limitations of microscopic diagnosis. This study was done to compare conventional microscopy with an antigen detecting ELISA kit and the PCR based method for detection of Giardia lamblia in human fecal specimens and it was conducted on (168) patients attended out-patient clinics at Zagazig University Hospital complaining of variable gastrointestinal problems, during the period from June 2015 to March 2016. Fecal samples were collected from every patient. Each sample was divided into 2 parts. The first portion was concentrated by formalin-ether sedimentation technique. Microscopic examinations by direct wet mount using saline and Lugol’s iodine were carried out. The second portion was used for performing ELISA and PCR. Out of the 168 stool specimens examined, 54 (32.1%) were positive and 114(67.9%) were negative for Giardia lamblia by microscopy. The highest percentage of giardiasis was detected in children younger than 6 y of age (41.7%). Giardia lamblia infection was related to the residence of patients and more positive cases were detected in rural 39 (40%) compared to urban 15 (21%) areas with a significant statistical difference between. On comparing ELISA test against microscopy, 49 (29.2%) stool samples were positive. Its sensitivity was 90.7 %, while the specificity was 100%. For the PCR technique, on comparing it against microscopy, 56 (33.3%) stool samples were positive,(4) negative samples by microscopy were positive by PCR methods. The sensitivity of PCR was 96.3% , while the specificity was 96.5%. In conclusion: PCR appears to be more sensitive and valuable for rapid and proper diagnosis of G.lamblia in humans.