INTRODUCTION: It is known that the larvae of ascarids have migrating phase before they reach the intestine. Stewart (1916) reported the pulmonary migration of ascaris larvae in normal host. Beaver et al. (1952) demonstrated the ascaris larvae of animal origin from the biopsied human liver, and applied the term "visceral larva migrans" to the migration of larval nematodes in unsuitable hosts. Either in normal or abnormal host, the migrated larvae cause inflammatory changes in the tissues and produce corresponding symptoms. There have been a considerable number of anthelminthics for the ascaris adult worm, but very few reports concerning the migrating larvae. Smirnov (1932) found no larvicidal effect of santonin and chenopodium oil on the migrating phase. Snyder (1961) also reported that diethylcarbamazine did not relieve the symptoms of visceral larva migrans. Recently, thiabendazole has appeared as a broad spectrum anthelminthic and Brown (1961) reported that the chemical inhibited the development of helminth larvae affecting the migratory phases of roundworms and kidney worms in swine. The present study was designed to confirm the previous reports concerning the anthelminthic effect of thiabendazole and to examine the mechanism of its activity. MATERIALS: Animal: White mice, weighing 18-26 gms, were used regardliss of sex. Parasites: Eggs from the 3cm distal portion of uteri of Toxocara canis and Ascaris lumbricoides were sampled and cultured in 0.5% formalin solution under room temperature for 40-50 days. The embryonated eggs were used for the experiment. Virus: Infuenza A/swine/1957/12 N.I.H., U.S.A. December 20, 1965. Chemical: Thiabendazole; 2-4'-thiazolyle)-benzimidazole, Merck Sharp and Dohme Co. 50% aqueous suspension of the chemical was used for experiment. METHODS: White mice were infected each orally using the stomach tube with 500 eggs of canine-ascaris or 800-1,000 eggs of human ascaris according to the experimental purposes. The viral infection was done by inhalation of 2-3 drops of emulsion containing viurs, and the drug was given by stomach tube. The average dose was 250 mg/kg. Recovery of larvae from the tissues: The larvae in the brain were examined under the microscope by pressing the tissue between two slides. The tissues of liver, lung, and carcasses were macerated with Waring blendor. The macerated tissue was suspended in 20 cc freshly prepared artificial gastric juice (pepsin 1 gm, HCL 0.5 cc, NaCL 0.85 gm, distilled water 100 cc), and incubated over night at 37 degrees C. The sample was centrifuged and the sediments examined for larvae. Inthe first experiment, the fate of the migrating larvae after drug administration was determined in early observation group and late observation group. The early observation group: Three days after the infection of 500 eggs of Toxocara canis, 30 of the mice were diviede into two subgroups; having had a single dose and three doses of drug respectively. Four days after the first dose, the mice were sacrificed and the larvae in tissue were examined. The late ...

The 16 cases of Clonorchis sinensis infection were divided into 6 groups, according to the method of administration of 1, 4-Bis-trichlormethyl-benzol. The number of egg-out and clinical manifestation of pre.and post drug administration were observed. 1. In all groups, the number of ova transiently increased at the early stage of treatment and followed rather abrupt decrease reaching to E.P.G. zero by Stoll's method on 4 weeks after the medication, except group 6 which showed a few ova by M.G.L. method. 2. Subjective symptoms: fatigability, disappetite and other general complaints by the drug administration were markedly improved in all cases. 3. Blood counts and bleeding time were within normal value before and after the treatment. 4. Liver function test was normal during pre-and post-treatment except case No. 9. Serum alkaline phosphatase of No.9 was high level lbefore treatment, but recovered to noraml level 3 weeks later of the drug administrations. 5. SGOT and SGPT in 10 cases examined showed normal value. 6. The level of serum protein was not changed during observation period. 7. Urine albumin was noted in 2 cases before medication, but they also converted to negative within 3 weeks. Serum creatinine were all normal limits. 8. Bradycardia were noted in 2 cases during observed no significant abnormalities of EKG. Serum electrophoresis were also normal limits.

Single dose(1.0 cc) of 20 % 2, 6-diiodo-4-nitrophenol solution was injected to 82 hookworm infected cases and 79% of them became egg-negative within 2-3 weeks after the injection. Mild to severe local pain were experienced for several minutes in all cases. Two cases complained of paralysis of the arms of the same side. The tablet of the same formula was given orally to 21 cases for 1-4 days. The 2-4 day course with 360 mg/day were enough to eliminate the parasite, and showed no systemic side effects.