ABSTRACT
Experimentally infected rats with 50 metacercariae of Clonorchis sinensis each were treated orally with different dosages of praziquantel. About 100 rats were divided into 8 groups in each developmental week after infection (from the first to 8th week after infection) and 24 rats served as untreated controls. In each developmental week after infection, about 15 rats divided into 4groups including control group(3 to 5 rats) were used to determine for the curative activity of praziquantel against C. sinensis. The experimentally infected rats in each developmental weeks after infection received praziquantel 1 x 100 mg/kg x 3 days , 3 x 100 mg/kg x 1 day and 3 x 100 mg/kg x 2 days. The effects of the drug were evaluated by the worm recovery rates, morphological changes of the worms and the number of eggs per gram of feces (EPG) after treatment. The feces of individual rats were collected once in a week at one week before and 4 weeks after treatment, and the number of Clonorchis eggs were examined by Stoll's egg counting method. The necropsy was performed on 4 weeks after treatment. The liver and the bile ducts were examined immediately after the dissection, and all of the worms recovered from the liver immersed in warm saline solution in a small petri dish in order to observe the motility of individual worms. After that, all worms obtained from the treated and untreated control rats were fixed in 10 percent formalin solution. The whole mount specimens were prepared by Semichon's acetocarmine stain for the study of morphlogical changes. In the treatment with dosage of 1 X 100 mg/kg for 3 consecutive days, relatively low worm recovery rates were shown in the early stages of infection than those of control groups. However there was no differences of the worm recovery rates between the later stages of infection (7 to 8 weeks after infection) and control groups. In the early stages of infection, the worms recovered in the bile ducts of each treated rats showed morphologically intact as normal control groups, however in the later stages of infection the worms showed damage of their reproductive organs such as testes, seminal receptacle and ovary etc. In the treatment with dosage of 3 X100 mg/kg X 1 day, the recovery rates of the worms in all developmental weeks after infection were considerably low and some growth inhibition of the worms were also noted. The worms recovered from the bile ducts in all developmental stages were seriously damaged in their reproductive organs, such as testes, seminal receptacle, ovary, Mehlis' gland, uterus and vitelline glands etc. The hyaline degenerations were also observed on the parenchymal tissues in the dead worms. The mean EPG values in this group were markedly reduced at the first 2 weeks after treatment. However the low values of EPG were generally noted at the 3rd to 4th week after treatment. On the other hand, in the treatment with dosage of 3 X 100 mg/kg X 2 days, no more the living worms was recovered in all developmental stages of Clonorchis . The dead worms recovered from the bile ducts were so seriously damaged that the morphological changes could not be observed. The mean EPG values in this group were markedly reduced during the first 2 weeks after treatment. At the 3rd week after treatment EPG value became negative in the most of all treated groups. No more the Clonorchis eggs were detected at the 4th week after infection, but only a very small numbers of eggs were found by the concentration method. From the above results, it is obvious that praziquantel exhibits a high degree of activity against Clonorchis sinensis in the rats, with no apparent differences in the efficacy against each developmental stage.
Subject(s)
Clonorchis sinensis , Rats , PraziquantelABSTRACT
The new drug niclofolan (bayer 9015, Bilevon), 5,5'-dichloro-2,2'-dihydroxy-3, 3'-dinitrobiphenyl, has been used in the treatment of Paragonimus westermani in dogs and cats and P. iloktsuenensis in rats. It was proved that administration of daily dose of 1.0 mg/kg body weight for 3 days or in 2 doses of 2.0 mg/kg body weight by alternate days were evidently effective for the infected dogs, cats and rats with the lung flukes, and toxic manifestations were not found.
Subject(s)
Paragonimiasis , Paragonimus westermani , Dogs , Cats , Rats , NiclofolanABSTRACT
A single dose (2.0, 5.0, 10.0 mg/kg) of pyrantel embonate given to three groups consisting 301 children with Ascaris lumbricoides infection achieved a cure rate of 91.3%, 94.4% and 98.9% respectively. Whereas in the other two groups of 71 and 75 patients who received 75 mg/kg body weight with piperazine adipate 2 or 3 consecutive days, the cure rates were 62.0% and 74.7% respectively. Administration of a single recommended dose of santonin-kainic acid complex given to 77 patients achived a cure rate of 80.5% with 91.0% of egg reduction rate. The cure rate resulting from a single lowest dose 2.5 mg/kg pyrantel embonate was significantly higher than those of piperazine adipate and santonin-kainic acid complex in the mass treatment for ascariasis. in addition to the group of 2.5 mg/kg pyrantel embonate treatment, the side effect was lesser than those of the other groups. Considering the efficacy and safety of pyrantel embonate against Ascaris lumbricoides, it would be one of the useful agents for the mass treatment of Ascaris control.