• Journal of Life Science
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• v.20 no.10
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• pp.1556-1562
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• 2010

This study examined the histopathologic and electron microscopic findings of aborted fetuses from pregnant dairy cows naturally infected with Neospora caninum (N. caninum) at four farms in Gongju city and Yeonki gun of Choongnam province. Systemic subcutaneous edema was observed in the aborted fetuses. The necropsy revealed considerable serosanguinous fluid in the body cavity of the aborted fetuses. Light microscopy showed the infiltration of many inflammatory cells consisting of macrophages, lymphocytes and mononuclear cells, accompanied by congestion, hemorrhage and necrosis of myocardiac cells and hepatocytes in the liver and heart of the aborted fetuses. In the liver, clusters of tachyzoites were formed in the cytoplasm of hepatocytes and the interstitial tissue. In the brain, many tissue cysts of various sizes were observed in the nerve cells and their adjacent areas. Tissue cysts had a round shape and contained a large amount of bradyzoite. In addition, there was diffuse gliosis accompanied by congestion and hemorrhage and focal necrosis in the brain. Infiltration of microglial cells were observed at the periphery of the focal necrosis and perivascular area in the brain. Electron microscopy showed that the tissue cyst wall had a thickness of approximately 1 ${\mu}m$ with an irregular shape. On the interior side, more than 100 bradyzoites with lengths of 2-5 ${\mu}m$ and widths of 1-2 ${\mu}m$ were observed. The nucleus of in the bradyzoites was located approximately 1-1.5 ${\mu}m$ anterior to the posterior tip of the zoite. In the cytoplasm between the nucleus and the posterior tip, there were many amylopectin granules, electron-dense small-sized and electron-thin large-sized round granules, homogeneously electron-dense rhoptries and micronemes oriented perpendicularly to the zoite pellicle. To summarize, tissue cysts were identified on electron microscopy from the aborted fetus from N. caninum seropositive pregnant cow by the ELISA. This led to the confirmed presence of N. caninum.

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.201-210
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• 1995

This study aims to assess the possible strain-dependent variations in detection of ToxopLosmn antigens and antibodies. The virulent RH strain or avirulent Beverley strain of T gondii were injected into mice, intraperitoneally, and their antigens, antibodies and parasites were identified from the blood or tissues: liver, brain and spleen by ELISA, Western blot and PCR. In mice infected with RH strain, circulating antigens and parasitemia were first detected from 2 days after infection, and ToxopIasma DNA were found in the blood, liver, brain and spleen from 3 days after infection. It was impossible to detect specific IgM and IgG antibodies to T gondij and any specific band was not found by Western blot. In mice infected with Beverley strain, circulating antigens were detected between day 10 and day 35. The Toxoplusma DNA was found in the blood and liver from day 15 until day 60, and in the brain from day 20. But Toxoplosma DNA in the spleen were mainly detected between day 10 and day 30. The IgM antibodies were first appeared on day 10 post-infection, and were noted obviously increased between day 15 and 25. The IgG antibodies were first detected on day 15, and showed progressively increased titers. The antibody binding bands were specific according to infection period. Sera from mice infected with Beverley strain reacted mainly with the antigen of 27.5-kDa and 32.5-kDa. In conclusion, mice infected with RH strain revealed Toxoplosma antigens strongly, but not antibodies. However. mice infected with Beverley strain revealed both the Toxoplasma antigens and antibodies. The present results showed that immune responses are different between avirulent and virulent T gonnii.