Resting cysts of the soil ciliate Colpoda cucullus Nag-1 were found to be highly resistant to UV light (254 nm); the presumed UV dose required for 99.9% inactivation was 571 mJ/cm2. On the other hand, in case of vegetative Colpoda cells, the presumed UV dose required for 99.9% inactivation was 40 mJ/cm2). We found that the nuclei of resting cysts were surrounded by autofluorescent particles (nuclei-surrounding particles; NSP). The cyst wall components (lepidosomes and ectocyst layer) were also auto-fluorescent. These auto-fluorescent structures may absorb UV light to protect cytoplasmic components.

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In this study, potential of the Percoll density gradient centrifugation method for separation of bovine red bold cells (RBCs) infected with each merozoite type of Babesia ovata was examined. By the Percoll density gradient centrifugation, bovine RBCs infected with active forms of B. ovata merozoites were essentially collected from one of the layers. Moreover, this method made it possible to eliminate its crisis forms, a morphologically abnormal intraerythrocytic form, effectively. Moreover, no adverse effect on viability of B. ovata merozoites was found. Our results suggest that this method will be applicable to sample preparation for biological analyses which require active forms of B. ovata merozoites.

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The present study evaluated serum-free GIT medium for the in vitro culture of Babesia bigemina, Babesia divergens, and Theileria equi. Parasite growth was compared with parasites grown in cultures containing M199 or RPMI1640 media with serum. The serum-free GIT medium supported the continuous in vitro culture of B. bigemina for 40 days. B. divergens growth was continuously cultured for 32 days in the serum-free GIT medium, and the parasite growth was similar to that in RPMI1640 with 10 % fetal calf serum and higher than the growth in M199 medium with 10 % fetal calf serum culture systems. Serum-free GIT medium supported the growth of T. equi for only 24 days, while the growth was sustained for 32 days in serum-free GIT medium supplemented with hypoxanthine. Parasite growth was similar to that in M199 medium supplemented with 40 % horse serum and hypoxanthine. The morphology of the three kinds of parasites was similar in serum-free GIT and the standard media with serum. Therefore, the present study indicated serum-free GIT medium alone for short-term in vitro cultivation of B. bigemina and B. divergens and supplemented with hypoxanthine for the in vitro culture of T. equi.

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Theileria orientalis often causes clinical anemia in cattle. In the present study, the red blood cell (RBC) indices of cattle, as measured in T. orientalis-endemic regions of Hokkaido, Japan, were analyzed. In comparison with the non-infected animals, the mean values for RBC counts, hematocrit, and hemoglobin concentration (HGB) were lower in T. orientalis-infected Holstein and Hereford cattle but not in Japanese Shorthorn and Angus, suggesting that the hemolysis induced by T. orientalis is not pronounced in the later. Anemic animals (HGB < 8 g/dl) were detected only in Holstein and Hereford, and the anemia rate was higher for Holstein than that for Hereford. The mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values in the T. orientalis-infected but non-anemic animals were significantly higher than those for the non-infected Hereford, but not for the Holstein, suggesting that the host response to hemolysis influenced anemia development. To clarify this phenomenon, three Holstein calves experimentally infected with T. orientalis were monitored for the parasitemia and RBC indices. Among the infected animals, a calf with low parasitemia had elevated MCV and MCH values, but lacked anemia. In contrast, despite elevated MCV and MCH values, HGB in the calf with high parasitemia dropped to a low value. These findings indicate that the cattle breed, parasitemia level, and host response may influence anemia development in T. orientalis-infected cattle.

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Sixty cases of one- to seven-week old stunted diarrheic native turkey poults from the native turkey-raising provinces of Iran were examined for the presence of intestinal protozoan infections. Forty-seven cases out of 60 had one or more intestinal parasites. Based on fecal, histological, and transmission electron microscopic examinations, Cryptosporidium spp., Hexamita sp.p, Cochlosoma sp.p, Coccidia spp., Chilomastix spp., and Trichomonas spp. were identified. The protozoan infections were associated with diarrhea and unthriftiness.

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