In vivo replicative status and envelope heterogeneity of equine infectious anemia virus in an inapparent carrier.
Abstract: The distribution and replicative status of equine infectious anemia virus (EIAV) DNA in the tissues of a well-characterized inapparent carrier horse were established by using the PCR technique. The EIAV pol region could be amplified in all of the tissues tested, including the cerebellum and periventricular tissue, at concentrations approximately 10(5)-fold less than in the same tissue from an acutely infected horse. Further analysis of the EIAV genome, with primer pairs diagnostic for sequential stages of reverse transcription, suggests that EIAV DNA in the brain, liver, and lymph nodes was incompletely synthesized. The products of reverse transcription were found to diminish progressively during first-strand synthesis, while products indicative of second-strand synthesis were observed only in kidney and spleen DNA samples. Sequences specific for different regions of the envelope could not be amplified from any of the tissues of the inapparent carrier, suggesting that the envelope is highly variable and may be subject to extensive drift. Together, the data suggest that low levels of EIAV replication persist without causing clinical disease in an inapparent carrier.
Publication Date: 1994-04-01 PubMed ID: 8139056PubMed Central: PMC236760DOI: 10.1128/JVI.68.4.2777-2780.1994Google Scholar: Lookup
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- Journal Article
Summary
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This research paper studies the proliferation and characteristics of the equine infectious anemia virus (EIAV) in a horse that shows no apparent signs of the disease. It suggests that the virus can reproduce at low levels and exhibit significant differences in its envelope proteins, without causing visible health problems in the carrier.
Methodology and Participants
The research was conducted on a horse identified as a silent carrier of the EIAV. Using the polymerase chain reaction (PCR) technique, the researchers studied the distribution and replication of the virus in various tissues of the horse, including the brain, liver, lymph nodes, kidney, spleen, and more.
Findings: Distribution and Replicative Status
- The EIAV pol region, a critical part of the viral genome, could be amplified in all the tested tissues. However, the amount was around 10^5 times less compared to the same tissue of a horse with acute infection.
- The viral DNA analyzed in the brain, liver, and lymph nodes appeared to be incompletely synthesized. The study suggests that this could be an indication of the virus’s replicative status, implying that viral replication is ongoing, but at low levels.
- There was a progressive decrease in the output during first-strand synthesis of viral DNA, suggesting that the majority of EIAV DNA in these tissues was not fully formed. This again indicates low levels of replication.
- Signs of second-strand synthesis, a further stage of replication, were observed only in the kidney and spleen samples. This suggests the virus is able to fully replicate in these tissues.
Findings: Envelope Heterogeneity
- Different regions of the virus’s envelope could not be amplified from any of the tested tissues. This suggests high variability in the EIAV envelope and potential for extensive drift, which means the virus may rapidly undergo mutations in these regions.
Conclusion
The research findings suggest that the EIAV might continue to replicate at low levels in an inapparent carrier, without causing clinical disease. Also, the virus appears to be highly variable, especially in its envelope region. This highlights the potential challenges in developing preventative treatments or vaccines for EIAV, given its ability to persist and evolve within a host.
Cite This Article
APA
Kim CH, Casey JW.
(1994).
In vivo replicative status and envelope heterogeneity of equine infectious anemia virus in an inapparent carrier.
J Virol, 68(4), 2777-2780.
https://doi.org/10.1128/JVI.68.4.2777-2780.1994 Publication
Researcher Affiliations
- Department of Microbiology, Immunology, and Parasitology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
MeSH Terms
- Animals
- Brain / microbiology
- Carrier State / microbiology
- DNA, Viral / genetics
- Equine Infectious Anemia / microbiology
- Genes, env / genetics
- Genes, gag / genetics
- Genes, pol / genetics
- Horses
- Infectious Anemia Virus, Equine / genetics
- Infectious Anemia Virus, Equine / growth & development
- Tissue Distribution
- Virus Replication
References
This article includes 17 references
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Citations
This article has been cited 5 times.- Leroux C, Craigo JK, Issel CJ, Montelaro RC. Equine infectious anemia virus genomic evolution in progressor and nonprogressor ponies.. J Virol 2001 May;75(10):4570-83.
- Hammond SA, Li F, McKeon BM Sr, Cook SJ, Issel CJ, Montelaro RC. Immune responses and viral replication in long-term inapparent carrier ponies inoculated with equine infectious anemia virus.. J Virol 2000 Jul;74(13):5968-81.
- Harrold SM, Cook SJ, Cook RF, Rushlow KE, Issel CJ, Montelaro RC. Tissue sites of persistent infection and active replication of equine infectious anemia virus during acute disease and asymptomatic infection in experimentally infected equids.. J Virol 2000 Apr;74(7):3112-21.
- Oaks JL, McGuire TC, Ulibarri C, Crawford TB. Equine infectious anemia virus is found in tissue macrophages during subclinical infection.. J Virol 1998 Sep;72(9):7263-9.
- Maury W, Perryman S, Oaks JL, Seid BK, Crawford T, McGuire T, Carpenter S. Localized sequence heterogeneity in the long terminal repeats of in vivo isolates of equine infectious anemia virus.. J Virol 1997 Jul;71(7):4929-37.
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