RESUMO
Paramphistomes are important parasites in veterinary medicine. There are few anthelmintic drugs available against them. The development of new drugs is urgently needed and this process can be accelerated through the development of rodent models for in vivo testing. Among the few paramphistomes that develop in rodents is the caecal fluke Zygocotyle lunata, a species with which several biological studies have been performed over several decades. Nevertheless, its use as a model for evaluation of anthelmintic drugs had not yet been evaluated. In the present study, we evaluated the efficacy of praziquantel (PZQ 300â¯mg/kg 5x), albendazole (ABZ 200â¯mg/kg 5x) and closantel (CLO 50â¯mg/kg single dose, 50â¯mg/kg 3x and 25â¯mg/kg 3x) for treatment of mice experimentally infected with Z. lunata. The animals were infected with 20 metacercariae of the parasite and were treated 30 days post-infection. Untreated groups were maintained as controls. Seven days after the treatments, the animals were euthanized for recovery and counting of parasites. We found that PZQ and ABZ, at the dosages and therapeutic schedule employed here, did not cause significant alterations in worm burden [worm counts 16.0⯱â¯2.8 (13-19), 17.6⯱â¯2.1 (14-19) and 16.2⯱â¯1.9 (13-18) (pâ¯=â¯0.51) in PZQ, ALB and control, respectively]. CLO 50â¯mg/kg in a single dose caused significant reduction in the number of parasites [treated: 1.8⯱â¯0.9 (1-3); control: 15.6⯱â¯2.5 (12-19)], although it did not result in complete elimination of the parasites in any animal. Despite the fact that three doses of CLO 50â¯mg/kg or CLO 25â¯mg/kg caused complete elimination of the parasites in most surviving animals, there was significant host mortality. In general, results here obtained are concordant with those of studies performed on ruminant paramphistomes. Given that Z. lunata can be maintained in laboratory rodents, it is a suitable model for screening anthelmintic drugs against paramphistomes.