Evaluation of the efficacy of gold nanoparticles on Giardia lamblia infection in experimental animals

Giardia lamblia (G. lamblia) is an important cause of severe malabsorption, weight loss, physical and mental retardation especially in infants and children throughout the world. Metronidazole (MTZ) is the standard drug used for their treatment which possesses several drawbacks with low efficacy. Gold nanoparticles possess a broad-spectrum antimicrobial activity and could be considered as a future alternative to many microbial agents. This study aimed to evaluate the anti-Giardia effect of gold nanoparticles as an alternative to MTZ. This study was done on 70 experimentally albino rats that were divided into three main groups with seven subgroups (each of 10 rats). The effect of MTZ and gold nanoparticles as single or combined therapy were evaluated. The effect was assessed by counting Giardia fecal cysts in the stool and trophozoites in the intestinal wash, histopathological, transmission and scanning electron microscopic examinations of the small intestinal tissues. Toxic tests of biochemical parameters of liver and kidney function were also performed. A significant reduction of the parasite number in the stool and small intestinal sections was apparent in treated infected rats compared with the infected non-treated ones. Gold nanoparticles showed the best result and the highest effect in the eradication of the parasite from the stool and the intestine with marked improvement in the intestinal mucosal injury caused by G. lamblia trophozoites. Gold nanoparticles had a toxic effect on the liver, with no kidney toxicity. Nanogold can be considered as a potential therapeutic agent and as a promising alternative therapy for G. lamblia infection. Further studies using various dosages with different durations of treatment with gold nanoparticles can be tested on Giardia lamblia infection.