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Characterization of natural occurring Pneumocystis carinii pneumonia
in pigs by histopathology, electron microscopy, in situ hybridization and
PCR amplification
J.A. Ramos Vara1, J-J. Lu2, A.J. da Silva4, K.T. Montone5,
N.J. Pieniazek4, C-H. Lee3, L. Pérez5, B.A. Steficek1, R.W. Dunstan1,
D. Craft6 and G.L. Watson1
1Animal Health Diagnostic Laboratory, Michigan State University,
East Lansing, MI, USA, 2Department of Pathology, Tri-Service General Hospital,
Taipei, Taiwan, 3Department of Pathology and Laboratory Medicine, Indiana
University School of Medicine, Indianapolis, In, USA, 4Division of Parasitic
Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA,
5Department of Pathology and Laboratory Medicine, University of Pennsylvania,
Medical Center, Philadelphia, PA, USA and 6Department of Pathology, Michigan
State University, East Lansing, MI, USA
Offprint requests to: Dr. José
Ramos-Vara, Animal Health Diagnostic Laboratory, College of Veterinary Medicine,
Michigan State University, East Lansing, MI48824, USA
Summary. Macroscopic, histologic,
ultrastructural, microbiologic, in situ hybridization (ISH) and PCR detection
results in three 8-week-old pigs naturally infected with Pneumocystis carinii
(PC) are described. All animals had a nonsuppurative interstitial pneumonia
and intra-alveolar Pneumocystis organisms with foamy eosinophilic and PAS
positive appearance. Ultra-structurally, PC trophozoites and cysts were
observed in pigs No. 2 and No. 3, with the former being much more numerous.
PC organisms were located on the alveolar surface or within the alveolar
septa. Trophozoites had numerous filopodia and were thin-walled. Cysts had
no or few filopodia, were thick-walled and contained intracystic bodies.
Using non-isotopic ISH on formalin-fixed, paraffin-embedded lung tissue
sections, PC DNA from pigs No. 2 and No. 3 hybridized with a probe specific
for PC ribosomal RNA (rRNA). Using primers specific for mitochondrial rRNA
gene (pAZ102-E/pAZ102-H), and for the internal transcriber spacers of ribosomal
gene of PC, PCR methods amplified a product in the lung of pigs No. 2 and
No. 3 using either frozen or formalin-fixed and paraffin-embedded lung tissue.
DNA from Pig No. 1 samples did not amplify with any primer. This is the
first time that molecular biology techniques (in situ hybridization and
PCR) have been applied to the study of porcine pneumocystosis. Histol
Histopathol 13, 129-136 (1998)
Key words: Pneumocystis carinii,
Pneumonia, Electron microscope, ISH, PCR
DOI: 10.14670/HH-13.129
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