A Simple Method for Demonstrating the Giardia Lamblia Trophozoite

Abstract

Giardia lamblia is a flagellated protozoan parasite of man. Only 2 stages i.e. the trophozoite and the cyst forms are observed in the life cycle of Giardia. The Giardia infection is acquired from drinking water or by eating food which is contaminated with cysts. The symptoms of the Giardia infection are foul smelling diarrhoea, flatulence, steatorrhoea, etc. Stool samples from the patients are examined for the detection of the motile trophozoites and cysts. As the trophozoites disintegrate rapidly, the stool sample should be observed within 15 minutes of its passage. Hence, we developed a staining method to stain the Giardia trophozoite permanently. Smears of the stool samples were prepared and they were fixed with methanol. The staining was done by using a 1% methylene blue solution. All the 15 known Giardia lamblia trophozoite positive samples were also found to be positive by the Methylene blue staining. The Giardia lamblia cysts could not be stained by this method. 20 stool samples were used as negative controls. We developed the methylene blue staining for demonstrating the trophozoite of Giardia, which is a very simple permanent staining method. The slides can be kept for a permanent record.