PMID- 16506914
OWN - NLM
STAT- MEDLINE
DCOM- 20060510
LR  - 20061115
IS  - 0002-9645 (Print)
IS  - 0002-9645 (Linking)
VI  - 67
IP  - 3
DP  - 2006 Mar
TI  - Evaluation of the effects of animal age, concurrent bacterial infection, and 
      pathogenicity of porcine reproductive and respiratory syndrome virus on virus 
      concentration in pigs.
PG  - 489-93
AB  - OBJECTIVE: To evaluate the influences of animal age, bacterial coinfection, and 
      porcine reproductive and respiratory syndrome virus (PRRSV) isolate pathogenicity 
      on virus concentration in pigs. ANIMALS: Twenty-one 2-month-old pigs and eighteen 
      6-month-old pigs. PROCEDURE: Pigs were grouped according to age and infected with 
      mildly virulent or virulent isolates of PRRSV. The role of concurrent bacterial 
      infection was assessed by infecting selected pigs with Mycoplasma hyopneumoniae 
      21 days prior to inoculation with PRRSV. On alternating days, blood and swab 
      specimens of nasal secretions and oropharyngeal secretions were collected. On day 
      21 after inoculation with PRRSV, selected tissues were harvested. Concentrations 
      of PRRSV were determined by use of quantitative real-time PCR and expressed in 
      units of TCID(50) per milliliter (sera and swab specimens) or TCID(50) per gram 
      (tissue specimens). RESULTS: Concentrations of virus were higher in blood and 
      tonsils of pigs infected with virulent PRRSV. Pigs infected with virulent PRRSV 
      and M hyopneumoniae had significantly higher concentrations of viral RNA in 
      lymphoid and tonsillar tissue. Coinfection with M hyopneumoniae resulted in a 
      higher viral load in oropharyngeal swab specimens and blood samples, independent 
      of virulence of the PRRSV isolate. Two-month-old pigs had significantly higher 
      viral loads in lymph nodes, lungs, and tracheal swab specimens than did 
      6-month-old pigs, independent of virulence of the PRRSV isolate. CONCLUSIONS AND 
      CLINICAL RELEVANCE: Multiple factors affect PRRSV concentration in pigs, 
      including pathogenicity of the PRRSV isolate, age, and concurrent infection with 
      M hyopneumoniae.
FAU - Cho, Jenny G
AU  - Cho JG
AD  - Swine Disease Eradication Center, College of Veterinary Medicine, University of 
      Minnesota, Saint Paul, 55108, USA.
FAU - Dee, Scott A
AU  - Dee SA
FAU - Deen, John
AU  - Deen J
FAU - Guedes, Alonso
AU  - Guedes A
FAU - Trincado, Carlos
AU  - Trincado C
FAU - Fano, Eduardo
AU  - Fano E
FAU - Jiang, Yin
AU  - Jiang Y
FAU - Faaberg, Kay
AU  - Faaberg K
FAU - Collins, James E
AU  - Collins JE
FAU - Murtaugh, Michael P
AU  - Murtaugh MP
FAU - Joo, Han Soo
AU  - Joo HS
LA  - eng
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  - Am J Vet Res
JT  - American journal of veterinary research
JID - 0375011
SB  - IM
MH  - Aging/*physiology
MH  - Animals
MH  - *Pneumonia of Swine, Mycoplasmal
MH  - Porcine Reproductive and Respiratory Syndrome/blood/*microbiology/*virology
MH  - Porcine respiratory and reproductive syndrome virus/*pathogenicity
MH  - Swine/microbiology/physiology/virology
MH  - Viral Load/*veterinary
MH  - Virulence
EDAT- 2006/03/02 09:00
MHDA- 2006/05/11 09:00
CRDT- 2006/03/02 09:00
PHST- 2006/03/02 09:00 [pubmed]
PHST- 2006/05/11 09:00 [medline]
PHST- 2006/03/02 09:00 [entrez]
AID - 10.2460/ajvr.67.3.489 [doi]
PST - ppublish
SO  - Am J Vet Res. 2006 Mar;67(3):489-93. doi: 10.2460/ajvr.67.3.489.