PMID- 10714643
OWN - NLM
STAT- MEDLINE
DCOM- 20000405
LR  - 20170214
IS  - 0300-9858 (Print)
IS  - 0300-9858 (Linking)
VI  - 37
IP  - 2
DP  - 2000 Mar
TI  - Pathogenesis of porcine reproductive and respiratory syndrome virus-induced 
      increase in susceptibility to Streptococcus suis infection.
PG  - 143-52
AB  - Eighty 3-week-old crossbred pigs were randomly assigned to six groups (13-14 
      pigs/group). Group 1 pigs served as uninoculated controls, group 2 pigs were 
      inoculated intranasally (i.n.) with Streptococcus suis serotype 2, group 3 pigs 
      were inoculated i.n. with a modified live porcine reproductive and respiratory 
      syndrome virus (PRRSV) vaccine, group 4 pigs were inoculated i.n. with the same 
      vaccine and with S. suis, group 5 pigs were inoculated i.n. with VR-2385 (a 
      high-virulence strain of PRRSV), and group 6 pigs were inoculated i.n. with 
      VR-2385 and S. suis. Pigs exposed to both PRRSV and S. suis were inoculated with 
      PRRSV 7 days prior to S. suis inoculation. The pigs were 26 days old when 
      inoculated with S. suis. Respiratory disease was significantly more severe in 
      groups 5 and 6. Mortality rate was the highest in group 6 (87.5%). This rate was 
      significantly higher than that observed in all other groups except group 4 
      (37.5%). The mortality rate in group 2, inoculated with S. suis alone, was 14.3%. 
      No pigs from groups 1, 3, or 5 died prior to the scheduled necropsies at 10 and 
      28 days postinoculation with PRRSV (DPI). To study the effect of PRRSV and/or S. 
      suis on pulmonary clearance by pulmonary intravascular macrophages, six pigs from 
      each group were intravenously infused with 3% copper phthalocyanine tetrasulfonic 
      acid in saline prior to necropsy at 10 DPI. Mean copper levels in the lungs of 
      pigs in groups 2, 5, and 6 were significantly lower than those in control pigs. 
      The mean percentage of lung tissue grossly affected by pneumonia at 10 DPI was 
      0%, 1%, 0%, 3%, 64%, and 62% for groups 1-6, respectively. Both gross and 
      microscopic interstitial pneumonia lesions were significantly more severe in the 
      VR2385-inoculated groups (5 and 6). PRRSV was isolated from bronchoalveolar 
      lavage fluid collected at necropsy from 100% of the pigs in groups 5 and 6, 71.4% 
      of pigs in group 4, 38.5% of pigs in group 3, and none of the pigs in groups 1 or 
      2. Streptococcus suis serotype 2 was cultured from the internal tissues of 7.7%, 
      28.6%, and 78.6% of the pigs in groups 2, 4, and 6, respectively. Streptococcus 
      suis serotype 2 was isolated from whole blood at necropsy from 7.7%, 35.7%, and 
      78.6% of pigs in groups 2, 4, and 6, respectively. Significantly more pigs in 
      group 6 had S. suis isolated from whole blood and internal tissues. In summary, 
      both high-virulence PRRSV and S. suis decreased copper clearance, and the 
      incidence of isolation of S. suis and PRRSV was higher in dually inoculated pigs. 
      PRRSV-induced suppression of pulmonary intravascular macrophage function may in 
      part explain PRRSV-associated increased susceptibility to S. suis infection.
FAU - Thanawongnuwech, R
AU  - Thanawongnuwech R
AD  - Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn 
      University, Bangkok, Thailand.
FAU - Brown, G B
AU  - Brown GB
FAU - Halbur, P G
AU  - Halbur PG
FAU - Roth, J A
AU  - Roth JA
FAU - Royer, R L
AU  - Royer RL
FAU - Thacker, B J
AU  - Thacker BJ
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Vet Pathol
JT  - Veterinary pathology
JID - 0312020
RN  - 0 (Antibodies, Viral)
RN  - 0 (Indicators and Reagents)
RN  - 0 (Indoles)
RN  - 0 (Organometallic Compounds)
RN  - 0 (Viral Vaccines)
RN  - 3VEX9T7UT5 (copper phthalocyanine)
SB  - IM
MH  - Administration, Intranasal
MH  - Animals
MH  - Antibodies, Viral/blood
MH  - Body Temperature
MH  - Bronchoalveolar Lavage/veterinary
MH  - Bronchoalveolar Lavage Fluid/virology
MH  - Disease Susceptibility/etiology/veterinary
MH  - Enzyme-Linked Immunosorbent Assay/veterinary
MH  - Immunohistochemistry
MH  - Indicators and Reagents/chemistry
MH  - Indoles/chemistry
MH  - Lameness, Animal
MH  - Lung/pathology
MH  - Organometallic Compounds/chemistry
MH  - Porcine Reproductive and Respiratory Syndrome/blood/*pathology
MH  - Porcine respiratory and reproductive syndrome virus/*pathogenicity
MH  - Random Allocation
MH  - Streptococcal Infections/immunology/pathology/*veterinary
MH  - Streptococcus suis/*pathogenicity
MH  - Swine
MH  - Viral Vaccines/immunology
EDAT- 2000/03/14 00:00
MHDA- 2000/03/14 00:01
CRDT- 2000/03/14 00:00
PHST- 2000/03/14 00:00 [pubmed]
PHST- 2000/03/14 00:01 [medline]
PHST- 2000/03/14 00:00 [entrez]
AID - 10.1354/vp.37-2-143 [doi]
PST - ppublish
SO  - Vet Pathol. 2000 Mar;37(2):143-52. doi: 10.1354/vp.37-2-143.