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Histopathologic Observation of the Aborted Fetus from Pregnant Dairy Cows Naturally Infected with Neospora caninum

Neospora caninum에 자연 감염된 임신우로부터 유산된 태아의 병리조직학적 관찰

  • Son, Jeong-Hoon (College of Veterinary Medicine, Chungnam National University) ;
  • Cho, Sung-Whan (College of Veterinary Medicine, Chungnam National University)
  • Received : 2010.09.02
  • Accepted : 2010.10.23
  • Published : 2010.10.30

Abstract

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.

충남 공주시와 연기군의 목장 4곳에서 Neospora에 자연 감염된 임신우로부터 유산된 태아를 병리조직학적, 전자현미경적으로 관찰하였다. 유산된 태아는 전신 부종과 함께 부검시 복강과 흉강은 혈액성 장액성 액체로 충만되어 있었다. 광학현미경적으로 심장과 간에서는 충 출혈 및 심근세포와 간세포의 괴사를 동반한 대식 세포, 임파구, 단핵구 세포로 구성된 많은 수의 염증세포 침윤이 관찰되었고, 간에서는 간세포의 세포질과 간질 조직에서 tachyzoite 집락이 관찰되었다. 뇌에서는 신경세포내와 주위에서 크기가 다양한 많은 수의 조직낭포가 관찰되었고, 조직낭포는 구형으로 두꺼운 막으로 싸여 있었으며 내부에는 많은 bradyzoite를 포함하고 있었다. 또한, 뇌조직에서는 충 출혈 및 국소성 괴사와 함께 광범위한 신경교증이 관찰되었고 국소성 괴사 부위 주위와 혈관주위에 소교세포로 구성된 많은 수의 염증세포 침윤이 관찰되었다. 전자현미경적으로 조직낭포의 막 두께는 대략 1 ${\mu}m$로 모양은 불규칙하였고, 내부에는 길이 2-5 ${\mu}m$, 폭 1-2 ${\mu}m$인 100여 개의 bradyzoite가 관찰되었다. Bradyzoite의 핵은 posterior tip으로부터 1-1.5 ${\mu}m$ 전방에 존재하였고, amylopectin 과립, 전자밀도가 높고 작은 구형인 과립과 전자밀도가 상대적으로 낮으나 큰 구형의 과립, 전자밀도가 균질한 rhoptry 및 zoite pellicle에 대해 수직방향으로 달리는 microneme이 핵과 posterior tip 사이의 세포질 내에서 관찰되었다. 이상의 본 연구는 ELISA검사를 통해 Neospora 항체에 양성반응을 나타내는 임신우로부터 유산된 태아에서 발견된 조직낭포를 전자현미경적으로 관찰하여 N. caninum임을 확인하였다.

Keywords

References

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