EJMS

Abstract

Giardia intestinalis (G. intestinalis) is considered one of the most common protozoan parasites in humans. It is a major cause of diarrhoeal illness as it infects millions of people worldwide. Giardiasis is generally treated with nitroimidazoles, nitrofurans, benzimidazoles and pyrantel pamoate. However, repeated reports of treatment failure, parasite resistance and drug toxicity emphasize the necessity to develop new treatments with greater efficacy and less side effects. The present study evaluated the in vivo efficacy of carvacrol against G. intestinalis in experimentally infected mice. Forty eight BALB/c mice were infected with Giardia cyst suspension containing 104cysts. Mice were divided into 4 groups: (G1) Infected untreated control group, (G2) Infected group treated by carvacrol (20 mg/kg), (G3) Infected group treated by carvacrol (40 mg/kg) and (G4) Infected group treated by metronidazole (15 mg/kg). Anti-giardial activity was assessed by faecal cyst counts, intestinal trophozoite counts and histopathological examination of hematoxylin and eosin (H&E) stained sections of the upper part of the small intestine. The anti-giardial activity of carvacrol on Giardia infection in mice evidenced by significant dose-dependent reductions of both faecal cyst and intestinal trophozoite counts was demonstrated. Carvacrol (40 mg/kg) reduced excretion of Giardia cysts in stools by 99.98% and trophozoites in intestine by 97.27%, while carvacrol (20 mg/kg) reduced faecal cyst excretion by 76.32% and trophozoites in intestine by 74.86%. There was a significant statistical difference in the carvacrol-treated groups when compared to the infected untreated control group. Carvacrol (40 mg/kg) was as effective as metronidazole in the reduction of faecal cyst and intestinal trophozoite counts with no statistical difference between the 2 groups. Histopathological examination revealed complete healing of the intestinal mucosa in mice treated with carvacrol (40 mg/kg) and metronidazole, and partial healing in those treated with carvacrol (20 mg/kg). The present study demonstrated the anti-giardial therapeutic effect of carvacrol in experimentally infected mice and highlighted its potential use as an alternative therapy for giardiasis in humans.