Determination of the specific gravity of certain helminth eggs using sucrose density gradient centrifugation.

The specific gravities of ten species of helminth eggs were determined using sucrose density gradient centrifugation. Fecal or egg concentrate was layered over a 3 to 54% sucrose density gradient. The gradient was then centrifuged at 800 g for 20 min, allowing 5 min for acceleration and 5 for deceleration. Bands formed were identified and measured. Refractive index was measured at the middle of narrow bands, or at the level at which the concentration of eggs was highest, in the case of wide bands or when no band was formed. The specific gravity corresponding to this refractive index was taken as the specific gravity of the eggs. The ten species of helminth eggs studied and specific gravities measured on three or four gradients were: Toxascaris leonina, 1.0559; Ancylostoma caninum, 1.0559; Toxocara canis, 1.0900; Parascaris equorum, 1.0969; Toxocara cati (embryonated), 1.1005; Ascaris suum, 1.1299; Trichuris suis, 1.1299; Trichuris vulpis, 1.1453; Taenia sp., 1.2251; and Physaloptera sp., 1.2376. These determinations agree with or approximate those of previous workers. The specific gravities of P. equorum, T. suis, Taenia sp., and Physaloptera sp., are reported for the first time.

Studies on flotation techniques for the recovery of helminth eggs from soil and the prevalence of eggs of Toxocara spp in some Kansas public places.

A technique for extracting Toxocara spp eggs from soil had a recovery efficiency ranging from 53% to 68%. Using the technique, 50 of 232 (22%) soil samples from city and university properties were found to be contaminated with eggs of Toxocara spp. Of 50 samples from highway rest areas, 8 (16%) were contaminated. From a public health standpoint, it was particularly noteworthy that 9 of 23 (39%) samples from sandboxes in student family quarters were contaminated with Toxocara spp eggs.

Prevalence of Toxocara spp. eggs in some public grounds and highway rest areas in Kansas.

Out of a total of 282 soil samples obtained from public areas, 58 samples contained Toxocara spp. eggs. This gave an overall prevalence of 20.6%. Highway rest areas were contaminated and childrens sand boxes had the highest percentage of recovery of all.

Experimental life cycle of Ascaridia columbae in intravenously infected pigeons, Columba livia.

The fate and routes of migration of infective larvae of Ascaridia columbae were studied in intravenously (i.v.) infected pigeons. Larvae were able to complete a trachael migration, and arrived at the small intestine where they established a patent infection. Granulomas were observed and histopathologically described in the lungs of i.v. infected birds.

Baylisascaris procyonis for testing anthelmintics against migratory ascarids.

Oral inoculation of mice with 340 embryonated eggs of the nematode, Baylisascaris procyonis, proved uniformly fatal as early as 13 days after inoculation and as late as 48 days. Mice given either 0.5% or 0.25% of pyrantel tartrate in dry feed were protected from cerebral migrations of the worm for 55 days. Treatment with pyrantel pamoate in the feed at the concentration of 0.2% given 7 days before inoculation and 5 days after inoculation also protected mice from migrations throughout the 55-day experiment. Embryonated eggs stored in 0.5% formalin in a 4-C refrigerator for 9 years have proved fatal to mice given doses of 340 eggs each.

Drug evaluation of pyrantel pamoate against Ancylostoma, Toxocara, and Toxascaris in eleven dogs.

Eleven dogs dosed at approximately the recommended rate of 1.029 mg of pyrantel pamoate/kg of body weight were used. The efficacy against Ancylostoma in the 11 dogs was 99% (av; min-max, 94-99%). In 4 dogs with both Toxocara and Ancylostoma, average efficacy against Toxocara was 96%, and in 5 dogs with both Toxoscaris and Ancylostoma, efficacy against Toxascaris was 93%. Only 2 dogs of the 11 were infected with the 3 species; the average efficacy was 90%. There appeared to be no activity against the Trichuris found in one dog and the Dipylidium found in another. Treated dogs did not vomit or have other noticeable ill effects.