tribendimidine and Trichinellosis

To evaluate the efficacy of tribendimidine (TBD) against 3 geographical isolates of Trichinella spiralis in mice.. Isolates of T. spiralis from Henan (hereinafter referred to as HnT.s), Yunnan (referred to as YnT.s) and Heilongjiang (referred to as HIjT.s) were used in the study. 144 Kunming strain mice were divided into 2 groups: 72 mice in group A (adult stage, treatment at 5 d after infection), and 72 mice in group B (encapsulated larva stage, treatment at 53 d after infection). Group A was further divided equally into 12 sub-groups. Mice in every 3 sub-groups were each infected orally with 200 T. spiralis larvae of the 3 isolates respectively, and the remained 3 subgroups served as untreated control. Mice in the 3 sub-groups infected with one isolate were orally treated with TBD at a single dose of 10, 20, and 30 mg/kg, respectively. Group B was treated as group A but with a course of TBD once daily at a dose of 100, 200, and 300 mg/(kg x d) for 7 d, respectively. Mice in group A were sacrificed 2 d post-treatment and adult worms were recovered from the small intestine and counted. Those in group B were sacrificed 10 d after completion of 7 d treatment. The intact diaphragm was removed and digested for collecting larvae. Worm burden and worm reduction of each treated sub-group were calculated and statistically compared with the respective control.. In group A, the mean worm burden in the treated sub-groups infected with HnT.s and YnT.s were all significantly lower than that of the controls (P < 0.01), with a mean worm reduction rate of 39.0%, 57.9%, and 86.0% in HnT.s sub-groups, and of 34.9%, 69.3%, and 92.2% in YnT.s sub-groups, respectively, showing an increase with the dosage, 2 mice in each of the 30mg/kg sub-groups were cured. The worm burden in the 10 mg/kg of HljT.s subgroup was similar to that of the control (P > 0.05), but was significantly lower in the other 2 sub-groups than that of the controls (P < 0.01). The worm reduction rate in the 3 sub-groups was 27.9%, 57.4%, and 60.7%, respectively. In all treated sub-groups of group B, the mean worm burden was significantly lower than that of the controls (P < 0.05), with a mean worm reduction rate of 57.8%, 75.4%, and 87.5% in HnT.s sub-groups, of 74.5%, 92.4%, and 99.1% in YnT.s sub-groups, and of 50.5%, 53.3%, and 61.6% in HljT.s sub-groups, respectively, with the 3 dosages.. Tribendimidine shows adequate efficacy on Trichinella spiralis adults and on encapsulated larvae of the 3 geographical isolates in mice, with better effect on Yunnan isolate.

Topics: Animals; Disease Models, Animal; Mice; Mice, Inbred Strains; Phenylenediamines; Trichinella spiralis; Trichinellosis

To observe the efficacy of oral administration of tribendimidine (TBD) at different dosages against Trichinella spiralis encapsulated larvae in murine striated muscle.. A total of 88 BALB/c mice were divided equally into 11 groups. Each mouse was infected orally with 50 T spiralis encapsulated larvae. At day 29 after infection, TBD was each orally administered to mice of the 11 groups with doses of 0 (control group), 50, 100, 150, 200, 250, 300, 350, 400, 450, and 500 mg/(kg x d), respectively. All mice were administered once a day and lasted for 6d, and untoward drug reactions for mice were observed. Mice were sacrificed at the 7th day after administration of TBD, the encapsulated larvae in diaphragmatic muscle, jugomaxillary muscle, pectoral muscle and gastrocnemius muscle were examined by pellet method, and the total, survival and dead worms were counted. The therapeutic effect was estimated on the basis of average quantity of encapsulated larvae per gram muscle.. During the administration period, no untoward reaction were observed in mice of 50-300 mg/(kg x d) groups. Mice in 350 and 400 mg/(kg x d) groups showed body hair dishevelment, emaciation and food-intake decrease, death rates were 25% and 50%, respectively. All mice in 450 and 500 mg/(kg x d) groups died on day 4 and 5 after TBD administration, respectively. In control group, the highest total burden (per gram) was found in diaphragmatic muscle, followed by jugomaxillary muscle, gastrocnemius muscles and pectoral muscles. TBD at dose of 50 mg/(kg x d) was unable to kill encapsulated larvae. In the rest groups, with the increase of drug dose, the total worm burden and the number of survival worms showed a decreasing trend in four kinds of muscles, and were significantly lower than that of the control group (P < 0.05 or P < 0.01). In 300 mg/(kg x d) group the number of survival worms in diaphragmatic muscle, jugomaxillary muscle, pectoral muscle and gastrocnemius muscle [8.6 +/- 1.7, 2.8 +/- 0.7, 3.9 +/- 0.8, and 0, respectively] were significantly lower than that of the control group [3648.1 +/- 989.2, 1266.4 +/- 812.3, 701.9 +/- 196.4, and 711.6 +/- 34.6] (P < 0.01). All encapsulated larvae in the four kinds of muscle died in 350 and 400 mg/(kg x d) groups. With the increase of TBD dosage, the mortality of encapsulated larvae increased in the muscles, reached up to 98.6%--100% in 300 m (kg x d) group (P < 0.01), and 100% in 350 and 400 mg/(kg x d) groups (P < .01).. Oral tribendimidine administered at 50 mg/(kg x d) to mice for 6 d is unable to reduce worm burden in muscle. Tribendimidine 300 mg/(kg x d) effectively kill encapsulated larvae and is a suitable dose against encapsulated larva stage. However, tribendimidine at doses of 350 mg/(kg x d) and above for 6d is toxic to mice and even causing death.

Topics: Administration, Oral; Animals; Larva; Mice; Mice, Inbred BALB C; Parasite Load; Phenylenediamines; Trichinella spiralis; Trichinellosis

To observe the efficacy of tribendimidine and albendazole against Trichinella spiralis in mice.. A total of 85 Kunming strain mice, infected orally with 100 T. spiralis larvae, was divided into 3 groups: group A (adult stage, 7 d after infection), group B (migrating larva stage, 15 d after infection), and group C (encapsulated larva stage, 35 d after infection). Group A (35 mice) was equally divided into 7 sub-groups, tribendimidine and albendazole were each orally administered to 3 sub-groups both with doses of 6.25, 12.5, and 25 mg/kg respectively, the untreated sub-group served as control. Groups B and C (25 mice each) were both divided equally into 5 sub-groups. Mice in 2 sub-groups were treated respectively with the 2 drugs in a dose of 100 or 200 mg/kg, the untreated sub-group served as control. Mice in group A were sacrificed 2 d post-treatment and adult worms recovered from the small intestine were counted. Those in groups B and C were sacrificed 15 d post-treatment and intact diaphragm was then removed from each mouse. The muscle of diaphragm was digested by digestive solution and the larvae were counted by stereomicroscope. Mean worm burden and mean worm reduction of each treated group were calculated and statistically compared with the control.. The mean worm burden in sub-groups of group A treated with tribendimidine was significantly lower than that of the control (P<0.01) with a mean worm reduction of 63.3%, 86.2%, and 98.5%, respectively. In the same batch of mice treated with albendazole at a single dose of 6.25 and 12.5 mg/kg resulted in similar mean worm burden compared to the control (P<0.05). While in the sub-group received albendazole at a higher dose of 25 mg/kg, the mean worm burden was significantly lower than that of the control (P<0.05), with a mean worm reduction of 41.2%. The mean worm burden in group B was significantly lower than that of the control (P<.01). The mean worm reduction in the 2 sub-groups treated with tribendimidine or albendazole was 64.4% and 89.6%, or 56.7% and 78.4%, respectively. In group C, significantly lower mean worm burden was only found in the subgroup treated with albendazole at a higher dose of 200 mg/kg than the control (P<0.01) with a mean worm reduction of 71.8%. No effect was seen in the other 3 groups.. Tribendimidine exhibits potential effect against adult and migrating larva stage of T. spiralis in mice, but lacks effect against encapsulated larva stage of the parasite. Albendazole administered at a larger or multiple doses to mice endorses effect against its adult, migrating larva and encapsulated larva stages.

Topics: Albendazole; Animals; Disease Models, Animal; Female; Larva; Mice; Mice, Inbred Strains; Phenylenediamines; Treatment Outcome; Trichinella spiralis; Trichinellosis