Dr. Holló Ferenc szerk.: Parasitologia Hungarica 3. (Budapest, 1970)

The anthelminthic action of tetramisole is due to selective interference with succinate-dehydrogenase activity of worm muscles which leads to paralysis. The drug has a broad anti-nematode spectrum being effective in animals against Haemonchus contor tus , Ostertagia circumcincta

, Trichostrongylus spp., Nematodi- rus spp., Chabertia ovina

, Oesophago

s

tomum Columbian

um

, Dictyo- caulus filaria and D. viviparus (12, 17, 13, 15, 14-, 16), also against Ascaridia galli

, Heter

akis gallinarum

, Capillaria ob- signata (5), as well as Hyostrongylus rubidus and Ascaris suum (19). It has no effect on tapeworms, flukes, protozoa or bacteria. A single, small dose of tetramisole has an effect of 6893 fo on Ascaris lumbricoides infection in human literature (2,7, 1, 23) without any marked undesirable and toxic effect. Reports on its efficacy in hookworm infection are not in complete agreement. A single dose of 2,5 mg/kg body weight generally exerted an effect of 60 fo. In a study covering only a few cases it proved ineffective in trichurosis and was only slightly effective in enterobiosis (22). Prior to clinical trials the study described in this paper was designed to obtain some information on the in vitro action of tetramisole and on the mechanism involved. Materials and Methods Ascaris suum was employed as the test worm on which to study the anthelminthic effect of tetramisole in vitro. According to many authors this species is identical with the nematode parasite of man,

Ascaris lumbricoides

. Albeit there exist objections to this opinion, all experts do agree that the biological and epidemiological features of porcine Ascaris are closely related to those of human Ascaris

. Worms obtained from pigs killed in a slaughterhouse were transported to the laboratory in a vacuum flask containing physiological saline solution at 37° C. The most vigorous specimens of