Uptake of sulfur-35-labeled carbon disulfide by Ascaridia galli (roundworm) and its chicken host

1. 1. In vitro experiments using Ascaridia galli and S 35-labeled carbon disulfide indicated that CS 35 2 was taken up by the worm as a vapor. When uptake of drug was compared with ligated and nonligated worms, no differences could be demonstrated, indicating that CS 2 entered the worm via the cuticle. 2. 2. Excluding size differences inherent between male and female worms, in vitro or in vivo tests showed that sex did not influence drug uptake. There was an indication that the number of μg of drug per worm was greater for smaller worms than for larger ones, but not enough worms were tested to establish this point statistically. 3. 3. As exposure time to CS 35 2 was increased geometrically at a constant dosage, a saturation point was approximated for female ascarids treated in vitro. This was also true when dosage was increased geometrically and exposure time was kept constant. In both cases the saturation point was near 3.0 μg per mg of worm. 4. 4. Individual worm analysis revealed that the body fluid took up the greatest quantity of S 35 equivalents of CS 35 2 per mg of tissue. Body fluid was followed, in respect to drug uptake, by the reproductive system, intestine, and body wall, respectively. 5. 5. In vivo studies using the chemotherapeutic dose of CS 35 2 showed that S 35 equivalents of CS 35 2 were present, in 22 tissues and organs of the chicken at 48 hours post-treatment. The highest concentration of S 35 was found in the gall bladder and the lowest in the brain. One hundred per cent efficacy was attained in each of the three chickens treated. The expelled worms contained an average of 0.087 μg of S 35 per mg. 6. 6. The chicken exereta, both urine and feces, had an average value of 0.245 μg of S 35 per mg. There was no difference in drug level in excreta containing worms or without worms.