Taher Elmi1, Shirzad Gholami2, Bahman Rahimi-Esboei3Zarah Garaili4, Mehdi Najm1 and Fatemeh Tabatabaie1*

1Department of Parasitology and Mycology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
2Molecular and Cell Biology Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
3Department of Parasitology and Mycology, Tehran University of Medical Sciences, Tehran, Iran.
4Department of Biostatistic, Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran.


Giardia lamblia is an intestinal protozoan parasite; hence, to diagnose the cyst, it is necessary to find a reliable, simpler and less expensive diagnostic method in the laboratory. Therefore, in order to choose a more sensitive, cheaper and applicable diagnostic method in the laboratory ;  three methods, namely, sucrose gradient, wet mount and formalin-ether in fecal samples from BALB/c mice infected with the protozoan Giardia, were studied. In this diagnostic laboratory study, 200 stool samples from infected mice (BALB/c) with Giardia were studied. Stool specimens from three direct smear method, formalin-ether and sucrose were prepared.  A total of 200 specimens for each method were prepared and examined by microscope.   Furthermore, it enhanced the accuracy check at each stage; the feces of healthy mice were used as negative controls for comparison. Stool examination revealed G.  lamblia cysts in mice infected BALB/c from 200 samples for each method. In the direct method, formalin – ether and sucrose gradient, 101 (55.00%), 166 (83.00%) and 180 (94.00%) cases were positive respectively. Therefore, the sucrose method has demonstrated the highest sensitivity (94.00%), compared to other methods.  According to the results of this study, sucrose is a sensitive method for high-throughput and cost-effective diagnostic method, than previous methods. Therefore, sucrose method is suggested suitable and can be used in place of formalin-ether. Given their potency, the sucrose gradient may be recommended to undergo futher studies.

Keywords: BALB/c, Giardia lamblia, Diagnostic method, Formalin – ether, Sucrose gradient.