PMID- 9150544
OWN - NLM
STAT- MEDLINE
DCOM- 19970708
LR  - 20170214
IS  - 0300-9858 (Print)
IS  - 0300-9858 (Linking)
VI  - 34
IP  - 1
DP  - 1997 Jan
TI  - Temporal and morphologic characterization of the distribution of porcine 
      reproductive and respiratory syndrome virus (PRRSV) by in situ hybridization in 
      pigs infected with isolates of PRRSV that differ in virulence.
PG  - 39-43
AB  - Three groups of 5-week-old cesarian-derived, colostrum-deprived pigs were 
      inoculated intranasally with either a high-virulence isolate (VR2385) or a 
      low-virulence isolate (VR2431) of porcine reproductive and respiratory syndrome 
      virus (PRRSV) or with uninfected cell culture and media. Formalin-fixed, 
      paraffin-embedded tissues from pigs euthanatized at 10, 21, and 28 days 
      post-inoculation were examined by in situ hybridization for PRRSV nucleic acid 
      using a digoxigenin-labeled antisense RNA probe approximately 1,000 nucleotides 
      in length. Alveolar macrophages were positive in the lungs of 9/9, 2/2, and 0/2 
      VR2385-inoculated pigs and 7/9, 1/2, and 2/3 VR2431-inoculated pigs at 10, 21, 
      and 28 days post-inoculation, respectively. More positive cells were detected in 
      lungs from VR2385-inoculated pigs compared to VR2431-inoculated pigs at 10 and 21 
      days post-inoculation. Positive cells within lymph nodes were tingible body 
      macrophages in germinal centers and macrophages or interdigitating dendritic 
      cells within the paracortical area. VR2385 was detected in the tracheobronchial 
      lymph node (TBLN) and mediastinal lymph node (MLN) of 7/9 and 9/9 pigs at 10 days 
      post-inoculation, but was only detected in the TBLN of 1/2 and 0/2 pigs and in 
      the MLN of 0/2 and 1/2 pigs at 21 and 28 days post-inoculation, respectively. In 
      contrast, VR2431 was detected in teh TBLN and MLN of 5/9 and 2/9 pigs at 10 days 
      post-inoculation and in the TBLN of 0/2 and 1/3 pigs and in the MLN of 0/2 and 
      0/3 pigs at 21 and 28 days post-inoculation, respectively. There were more 
      positive cells in TBLN and MLN in pigs inoculated with VR2385 at 10 days 
      post-inoculation. Macrophages located at the epithelial-lymphoid interface of 
      tonsilar crypts and within the paracortical areas were positive in tonsils of 
      9/9, 2/2, and 1/2 VR2385-inoculated pigs and 7/9, 1/2, and 1/3 VR2431-inoculated 
      pigs at 10, 21, and 28 days post-inoculation, respectively. Positive cells in the 
      thymic medulla were multinucleate and were only detected at 10 days 
      post-inoculation in 2/9 VR2385-inoculated pigs and 4/9 VR2431-inoculated pigs. 
      Positive cells within the spleen were few, spindle-shaped, located within smooth 
      muscle trabecula, and only present at 10 days post-inoculation in 3/9 
      VR2385-inoculated pigs. We conclude that the tissue tropism and distribution of 
      positive cells within tissues is similar for VR2385 and VR2431. However, tissues 
      from more pigs and more cells within tissues were positive in pigs inoculated 
      with VR2385 than VR2431 at 10 and 21 days post-inoculation. These findings 
      indicate that the more virulent isolate VR2385 may replicate better in vivo than 
      the less virulent isolate VR2431. This supports the hypothesis that an increased 
      ability to replicate in vivo contributes to increased virulence of PRRSV.
FAU - Haynes, J S
AU  - Haynes JS
AD  - Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State 
      University, Ames, USA.
FAU - Halbur, P G
AU  - Halbur PG
FAU - Sirinarumitr, T
AU  - Sirinarumitr T
FAU - Paul, P S
AU  - Paul PS
FAU - Meng, X J
AU  - Meng XJ
FAU - Huffman, E L
AU  - Huffman EL
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Vet Pathol
JT  - Veterinary pathology
JID - 0312020
RN  - 0 (RNA Probes)
SB  - IM
MH  - Animals
MH  - Cloning, Molecular
MH  - In Situ Hybridization
MH  - Lung/pathology/virology
MH  - Lymph Nodes/pathology/virology
MH  - Palatine Tonsil/pathology/virology
MH  - Porcine Reproductive and Respiratory Syndrome/*pathology/*virology
MH  - Porcine respiratory and reproductive syndrome virus/genetics/*isolation & 
      purification/*pathogenicity
MH  - RNA Probes
MH  - Species Specificity
MH  - Swine
MH  - Virulence
EDAT- 1997/01/01 00:00
MHDA- 1997/01/01 00:01
CRDT- 1997/01/01 00:00
PHST- 1997/01/01 00:00 [pubmed]
PHST- 1997/01/01 00:01 [medline]
PHST- 1997/01/01 00:00 [entrez]
AID - 10.1177/030098589703400106 [doi]
PST - ppublish
SO  - Vet Pathol. 1997 Jan;34(1):39-43. doi: 10.1177/030098589703400106.