The effects of Pyrantel-Oxantel on the Dipylidium caninum tapeworm: An in vitro study

Abstract

The present study aimed to evaluate, in vitro, the cestocidal effect of Pyrantel-Oxantel on the Dipylidium caninum tapeworm. Each intestine sample was obtained by means of a transversal incision of the abdominal area of each euthanized canine subject, individually dissected via longitudinal incision, and examined for the presence of D. caninum. An optical microscope was used to identify and verify proglottid morphology and viability based on its macroscopic appearance. The cestocidal effects of Pyrantel-Oxantel (75 mg pyrantel pamoate; 75 mg oxantel pamoate) were assessed in adult tapeworms (treated group, n= 21; control group, n= 21) placed on Petri dishes and incubated at 37 °C. One-hour post-incubation, the D. caninum cestodes treated with Pyrantel-Oxantel presented a 28 % decrease (P=0.001) in motility, which rose to a 52 % (P=0.0001) decrease by the end of the second hour. The control group (P=0.0001) presented 55.7 % motility for at least the first six hours of incubation and 4.2 % (P=0.001) motility by the end of the study, while 0 % motility was observed in the treated group by the end of the study. Pyrantel-Oxantel had a lethal effect (P=0.0001) on adult D. caninum, with 100 % mortality observed 6 h after in vitro post-incubation, while the control group presented 55.7 % viability after the same time period. In addition, Pyrantel-Oxantel reduced (P=0.001) tegument thickness by 42.5 % (10.24 ± 0.21 µm), while this was 17.81 ± 0.33 µm for the control group. The results of this study indicate that Pyrantel-Oxantel has a therapeutic effect on the presence of D. caninum, inducing both a reduction of the tegument thickness and increased mortality.