No description available.

No description available.

No description available.

No description available.

Two 16 mm color films were made to help fill a general need for instructional motion pictures in the area of Parasitology. One film "Haemonchus contortus, a Sheep Stomach Worm," deals with a nematode parasite of sheep, showing all stages of its external development and including a time-lapse sequence of the embryonation of the egg. The other film, "Some Parasites of Freshwater Fishes," shows six parasites; Ichthyophthirius multifiliis, Cotylurus erraticus, Dactylogyrus sp., Lernaea cyprinacea, Trichodina sp., and Diplostomum spathaceum for the first time in motion pictures. The films were photographed through a Wild dissecting scope and a Reichert Universal Camera Microscope, employing the techniques of brightfield, darkfield, phase contrast and Nomarski interference microscopy. The films are available from the Parasitology Laboratory of the Department of Zoology at Brigham Young University.

Oocysts of Isospora canis, an important protozoan parasite of dogs, must sporulate in the external environment in order to become infective. To determine the tolerance of these oocysts to different temperatures, oocysts ware collected from freshly passed feces, cleaned, and subsequently stored in unsporulated, partially sporulated, and completely sporulated conditions at temperatures ranging from +50 C to -50 C. Observations on survival for each group were determined periodically thereafter at intervals up to 64 days. The rate of sporulation was followed at 6 hr intervals for temperatures of 20, 25, 30, and 38 C. Completely sporulated oocysts ware more resistant to temperature extremes than unsporulated or partially sporulated oocysts; the optimum storage temperature for all stages was 4 C. This suggests that the development and survival of this parasite would be higher during mild spring and fall months than during cold winter and hot summer periods. The sporulation time for I. canis was 102 hr at 20 C, 96 hr at 25 C, 60 hr at 30 C, and 54 hr at 38 C; however, at the upper limit tested, more abnormal development occurred.

This study was undertaken to determine the effect of thiabendazole and haloxon on the free-living stages of Haemonchus contortus and to determine the suitability of the free-living stages for their use in primary drug evaluation for chemotherapy or for chemical control of free-living stages. Cleaned unembryonated ova, embryonated ova, first-, second-, third-, and exsheathed third-stage larvae were exposed to suspensions of 5.0%, 1.0%, 0.5%, 0.25%, 0.12%, 0.05%, and water soluble concentrations of each drug for exposure times of 0.25, 0.50, 1.0, 2.0, 4.0, 8.0, and 16.0 hours at pH 7.0 and 25° C. Survival was assessed by observing any subsequent development or motility. Thiabendazole was partially ovicidal to unembryonated ova at water soluble levels and after exposure of only 15 minutes. Exposure of longer than 4 hours was 100% lethal. No other stages were effected by thiabendazole. Haloxon was ineffective against all stages tested.

A systematic study of parasitic mites on kangaroo rats at the Nevada Test Site, Nye County, Nevada, was conducted from August, 1959, to December, 1961. The intent was to determine their kinds, numbers, seasonal occurrence, and ecological relationship with Dipodomys merriami merriami Mearns and Dipodomys microps occidentalis Hall and Dale in nuclear disturbed and contiguous undisturbed areas. Study areas were established in three major valleys -- Jackass Flats, Yucca Flat, and F renchman Flat.

No description available.

No description available.