Experimental studies on the efficacy of thiabendazole against the migratory stages of ascarids in mouse

Abstract

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 ...

Ascaris lumbricoidesandAscaris suumvary in their larval burden in a mouse model

“…In a mouse model of ascariasis, A. suum has tended to be the species of choice, with A. lumbricoides much less commonly used (Stewart, 1917, 1918; Sprent, 1952b; Bhowmick, 1964; Cho, 1967; Buske & Engelbrecht, 1968; Kumar & Singh, 1968; Maung, 1978; Massara et al ., 1990, 1991; Peng et al ., 2012; Gazzinelli-Guimarães et al ., 2013). To the best of our knowledge, no previous study has provided a detailed comparison of the larval burden of the two ascarid species derived from the two most important organs in early migration, the liver and the lungs.…”