Pharmacokinetics and therapeutic efficacy of levamisole in Ascaridia galli experimentally infected ducks.

This study investigated the pharmacokinetics and therapeutic efficacy of levamisole (LVS) after intravenous (i.v.) and oral administrations to healthy and Ascaridia galli-infected ducks by developing an infection model. Twenty-four two-week old ducklings were experimentally infected with A. galli. The ducks were monitored for the development of infection and after 8 weeks they were administered with LVS at a single dose of 30 mg/kg by oral or i.v. administration. Sixteen healthy ducks were subjected to the same treatment and served as control. Serial blood samples were taken for LVS determination with HPLC-UV and pharmacokinetic analysis was carried out based on the non-compartmental approach. The LVS therapeutic efficacy was determined 1 week post drug administration by intestinal worm count at necropsy. In vivo data on development of ascariasis in ducks showed that 8 weeks post inoculation the number of eggs per gram of feces reached at least 100 in each bird. After a single dose of LVS, no parasites were recovered upon necropsy. Results of the pharmacokinetic study showed no statistical differences between infected and non-infected birds for both routes of administration. The mean oral bioavailability was slightly below 50% in both experimental groups. In conclusion, the pharmacokinetics of LVS in ducks was not affected by experimentally-induced ascariasis. A single dose of LVS was found to be efficient against experimental ascariasis in ducks induced by in field isolates of A. galli.