Toxoplasma oocysts in cat feces were marked with a tracer amount of strontium-85 (85-SR), and were superficially buried simulating the natural disposal of feces by cats. Oocyst infectivity in Costa Rica was followed qualitatively and persisted for 1 year in three shaded sites, two moist, and one relatively dry site. Oocyst infectivity was quantitated in the Kansas deposit over a period of 18 months, including two winters. After initial mixing in soil, the level of infectivity remained fairly stable. Infectivity was recovered, probably from the surface on one Musca, several isopods, and earthworms. These data on persistence of Toxoplasma oocysts in soil support the concept that Toxoplasma infectivity in nature may be increased logarithmically by cats.

Antigen-treated lymphocytes from immune hamsters specifically protected not only macrophages, but also cultured fibroblasts and kidney cells infected with Toxoplasma gondii or Besnoitia jellisoni. Macrophages were not necessary for the protection of fibroblasts and kidney cells. A mediator that inhibited the intracellular proliferation of these microbes was obtained from immune lymphocytes in contact with specific antigen. Again, macrophages were not necessary for the elaboration of this mediator or its activity in kidney cells or fibroblasts. The mediator was microbe and host specific, had a molecular weight between 4,000 and 5,000, was resistant to heating at 560C for 30 min, and was sensitive to chymotrypsin, but resistant to ribonuclease and deoxyribonuclease. A single injection of Besnoitia mediator afforded better protection to hamsters infected with Besnoitia than did antibody. Whereas antibody lysed extracellular organisms, the microbe-specific mediators conferred immunity not only on macrophages, but also on other cells of the body, apparently the first such demonstration.

No abstract

In Costa Rica, a total of 640 samples from eight different vegetables used for raw consumption were analyzed for the presence of Cryptosporidium spp. oocysts, fecal coliforms, and Escherichia coli. Cryptosporidium spp. oocysts were found in 5.0% (4 samples) of cilantro leaves, 8.7% (7 samples) of cilantro roots and 2.5% (2 samples) of lettuce samples. A 1.2% contamination rate was detected in samples of other vegetables (radish, tomato, cucumbers and carrot). Oocysts of this parasite were absent from cabbage. A greater percentage of positive samples was found during the rainy season, and only in cilantro roots and lettuce was a positive linear correlation (P < 0.05) established between the presence of Cryptosporidium spp. oocysts and fecal coliforms and E. coli.

Fecal samples of 53 white face monkeys (Cebus capucinus) from some sites of Costa Rica were studied for blood and intestinal parasites. Animals were anesthetized with darts containing Telazol, blood and fecal samples were collected and all the material was studied in the laboratory. For blood parasites, Giemsa stain and Knott concentration was performed. Intestinal parasites were studied by direct examination in 0,85% saline solution and a Iodine solution. Haematoxylin stain was used for better protozoa identification. Strongyloides sp, hookworms, acanthocephalid eggs and other nematodes, as well as Tritrichomonas sp (more frequent) and other protozoa were found. The presence of at least one parasites was observed in 33.3% to 100% of the fecal samples with an average of 73.6%. There was not any correlation between sex and infection rate, but the presence of parasite was higher in heavier (older) animals. Microfilarias were the only blood organism detected.The reasons for these high infection rates could be explained for feed diversity, contaminated soil and water contact and sociability of these animals, among other factors.