In Vivo Efficacy of Drugs against Toxoplasma gondii Combined with Immunomodulators.

The aim of this study is to evaluate the effects of pyrimethamine (PYR) and sulfadiazine (SDZ) combined with levamisole and echinacea on the survival of mice infected with Toxoplasma gondii. For this, we used 99 specific pathogen-free BALB/c mice. All the mice were infected intraperitoneally with 10(5) T. gondii tachyzoites and were divided into 11 groups, each including 9 mice. Except for the control group, oral treatment was initiated in all groups 24 h post infection and was continued for 10 days. The treatment regimen included dual combinations of PYR (dose, 6.25 and 12.5 mg/kg/day) and SDZ (dose, 100 and 200 mg/kg/day), triple combinations of PYR + SDZ, and levamisole (dose, 2.5 mg/kg/day) or echinacea (dose, 130 and 260 mg/kg/day) and echinacea alone (dose, 130 and 260 mg/kg/day). We observed that an effective dose of the combination of PYR + SDZ and levamisole resulted in a statistically significant increase in the survival rate from 33.3% to 88.9%. Similarly, half the dose of this combination resulted an increase in the survival rate from 0% to 44.4% (p < 0.05). Survival rate also increased in the groups treated with the combinations including echinacea; however, the difference did not reach statistical significance. The triple combination of PYR-SDZ-levamisole could be an alternative treatment option in case of infections caused by T. gondii.