Background: Giardia lamblia is a flagellated unicellular eukaryotic micro-organism that commonly causes diarrheal disease worldwide. Although giardiasis is usually self-limited, it can develop into chronic and life-threatening disease. Most waterborne outbreaks (74.8%) were associated with drinking water as Giardia cysts are known to be resistant to chlorine at concentrations typically applied for water treatment.
Objective: To evaluate the effect of radioactive cobalt-60 and 254 nm ultraviolet (UV) irradiation on infectivity of Giardia cysts to mice.
Material and Methods: The study was conducted using 60 BALB/c mice divided into 6 groups with 10 mice in each. Group 1 received Giardia cysts treated with cobalt-60 (dose 0.25 KGy). Group 2 received cysts exposed to UV irradiation (wave length 254 nm). Groups 3-6 served as controls. Techniques used for evaluation of the infectivity of Giardia cysts included direct stool examination, duodenal aspiration with examination of the aspirate for the presence of Giardia cysts or trophozoites and histopathological examination of the small intestine of each mouse.
Results: Infectivity of Giardia cysts was reduced to 50% by experimental irradiation with cobalt-60 and 20% by UV, as shown by histopathological examination.
Conclusion: Low dose radioactive cobalt-60 and 254 nm UV radiations may be used as a control measure to prevent giardiasis, and as a mean of water treatment; but further studies are recommended for employment of both methods together or using smaller doses of each, thus benefitting from them both with less side effects.