Comparative efficacy of eugenol, eugenol nanoemulsion, and metronidazole against Trichomonas gallinae: An experimental study

Background: Trichomonas gallinae is a protozoan parasite responsible for canker in pigeons, a debilitating disease that causes significant economic losses. While metronidazole (MTZ) remains the primary treatment, the emergence of resistance is a growing concern. This study investigated the efficacy of eugenol and its nanoemulsion formulation against T. gallinae in both in vitro and in vivo settings. Aim: To evaluate the anti-trichomonal activity of eugenol, eugenol nanoemulsion, and MTZ against T. gallinae using in vitro and in vivo models. Methods: In vitro, T. gallinae trophozoites were exposed to varying concentrations of eugenol and eugenol nanoemulsion (0.625-10 mu g/ml), as well as MTZ (25 mu g/ml). Cytotoxicity was assessed using Vero cells. In vivo, 120 pigeons were experimentally infected and treated with either eugenol (10 mg/kg), eugenol nanoemulsion (10 mg/kg), MTZ (25 mg/kg), or left untreated. Treatments were administered daily for 5 days. Results: In vitro, both eugenol and its nanoemulsion at 10 mu g/ml achieved 100% lethality of T. gallinae after 48 hours, while MTZ reached the same effect within 24 hours. In vivo, MTZ and eugenol (at 25 mg/kg and 10 mg/kg, respectively) resulted in 100% recovery of infected pigeons 5 days post-treatment. Notably, eugenol nanoemulsion (10 mg/kg) achieved 100% recovery within just 4 days post-treatment. Conclusion: This study highlights the potential of eugenol and its nanoemulsion as alternative treatments for T. gallinae infections in pigeons. The eugenol nanoemulsion, in particular, demonstrated promising results with faster recovery rates compared to both MTZ and eugenol, suggesting it may be especially effective against MTZ-resistant strains. Further research is warranted to explore the efficacy and safety of these agents for treating T. gallinae infections in pigeons.