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Small Ruminant Lentiviruses in Sheep: Pathology and Tropism of 2 Strains Using the Bone Marrow Route
P Pinczowski1, L Sanjosé2, M Gimeno1
11 Department of Animal Pathology, University of Zaragoza, Spain.
Veterinary Pathology
|January 24, 2017
Summary
Two small ruminant lentivirus (SRLV) strains show different tissue tropism and pathology in sheep. Strain 496 causes arthritis, while strain 697 is linked to encephalitis, highlighting viral and host factors in SRLV infections.
Area of Science:
- Veterinary Virology
- Pathology
- Immunology
Background:
- Small Ruminant Lentiviruses (SRLVs) are significant pathogens in sheep and goats.
- Understanding the tissue tropism and pathogenicity of different SRLV strains is crucial for disease control.
- Autochthonous SRLV field strains present unique challenges due to their adaptation to local host populations.
Purpose of the Study:
- To comparatively analyze the tissue tropism and pathology of two distinct SRLV field strains (697 and 496) in sheep.
- To investigate the clinical, serological, and pathological outcomes following experimental inoculation with these strains.
- To determine the influence of viral and host factors on the clinicopathological manifestations of SRLV infection.
Main Methods:
- Experimental infection of Rasa Aragonesa lambs with SRLV strains 697 (nervous tissue origin) and 496 (articular origin).
- Periodic clinical, serological (ELISA), and molecular (PCR) monitoring of infected animals.
- Post-mortem examination including gross pathology, histopathology, immunohistochemistry (CD3, CD4, CD8, CD68, FoxP3), lung morphometry, and proviral DNA quantification.
Main Results:
- All infected lambs seroconverted and/or tested positive by PCR. Group B (strain 496) showed higher serological titers and more consistent PCR positivity.
- Strain 697 induced lung lesions and mild central nervous system (CNS) or carpal joint changes. Strain 496 caused severe carpal arthritis and interstitial pneumonia, with no CNS lesions.
- Proviral DNA was detected exclusively in tissues of group B lambs, indicating strain 496's higher replication and dissemination.
Conclusions:
- SRLV strain 496 is more virulent and arthritogenic than strain 697 in Rasa Aragonesa lambs.
- SRLV strain 697 is more likely to cause encephalitis, whereas strain 496 is associated with arthritis and pneumonia.
- Both viral and host factors contribute to the diverse clinicopathological outcomes observed in SRLV infections.
