Serologically silent, occult equine infectious anemia virus (EIAV) infections in horses.
Abstract: Molecular and serological techniques for Equine Infectious Anemia Virus (EIAV) diagnosis were compared using samples from 59 clinically normal horses stabled on five farms in the Santa Fe Province of Argentina. Of these 26 (44.1%) were positive in official AGID tests and/or gp45/gp90-based ELISA. Surprisingly 18 of the 33 seronegative horses were positive in a PCR against viral sequences encoding gp45 (PCR-positive/AGID-negative) with all but one remaining EIAV-antibody negative throughout a two year observation period. The gp45 PCR results are supported by fact that 7/18 of these horses were positive in the Office International des Epizooties (OIE) recommended EIAV gag gene specific PCR plus 2 of this 7 also reacted in a PCR directed predominantly against the 5' untranslated region of the viral genome. Furthermore sufficient quantities of serum were available from 8 of these horses to verify their seronegative status in sensitive Western Blot tests and demonstrate by ELISA the absence of EIAV-specific antibodies was not attributable to abnormalities in total IgG concentration. Studies involving 7 of the PCR-positive/AGID-negative horses to measure lymphocyte proliferation in the presence of PHA showed no significant differences between this group and control animals. In addition, lymphocytes from 2 of these 7 horses responded to peptides derived from gp90 and gp45. Together these results demonstrate that apparently clinically normal horses with no gross signs of immunodeficiency in terms of total IgG concentration or T helper-cell function can remain seronegative for at least 24 months while harboring EIAV specific nucleic acid sequences.
Copyright © 2016 Elsevier B.V. All rights reserved.
Publication Date: 2016-03-11 PubMed ID: 27066707DOI: 10.1016/j.vetmic.2016.03.007Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research investigates the occurrence of ‘silent’ infections of Equine Infectious Anemia Virus (EIAV) in horses— occurrences where the horses are infected but show no signs of the disease.
Research Methodology
- The study was conducted using samples from 59 clinically normal horses stabled on five farms in the Santa Fe Province of Argentina.
- The samples were tested using both molecular and serological techniques for EIAV diagnosis, such as official AGID tests and gp45/gp90-based ELISA.
Findings and Observations
- It was found that 26 horses (44.1% of the total) tested positive in the diagnostic tests used.
- Interestingly, an additional 18 of the 33 seronegative horses turned out to be positive in a PCR test against viral sequences encoding gp45. These horses are referred to as ‘PCR-positive/AGID-negative’.
- Most of these horses remained EIAV-antibody negative throughout the two year observation period, suggesting that they harbored the virus without showing serological signs of the infection.
- This observation was further supported as 7 out of the 18 ‘PCR-positive/AGID-negative’ horses were found positive in a EIAV gag gene specific PCR recommended by the Office International des Epizooties (OIE).
- Blood serum from 8 of the horses was found to have normal IgG concentration, supporting the argument that the absence of EIAV-specific antibodies was not due to abnormalities in total IgG concentration.
- Further studies involving measurements of lymphocyte proliferation in 7 of the PCR-positive/AGID-negative horses showed no significant differences, suggesting they had no visible signs of immunodeficiency.
Conclusion
- The study concludes that clinically normal horses with no apparent signs of immunodeficiency can harbor EIAV specific nucleic acid sequences for at least 24 months while remaining seronegative – thus being carriers of a ‘silent’ infection.
Cite This Article
APA
Ricotti S, Garcia MI, Veaute C, Bailat A, Lucca E, Cook RF, Cook SJ, Soutullo A.
(2016).
Serologically silent, occult equine infectious anemia virus (EIAV) infections in horses.
Vet Microbiol, 187, 41-49.
https://doi.org/10.1016/j.vetmic.2016.03.007 Publication
Researcher Affiliations
- Laboratorio de Diagnóstico e Investigaciones Agropecuarias, Sub- Dirección de Ganadería y Sanidad Animal, Ministerio de la Producción de la Provincia de Santa Fe, Boulevard Pellegrini 3100, 3000 Santa Fe, Argentina; Laboratorio de Inmunología, Cátedra de Inmunología. Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, 3000 Santa Fe, Argentina.
- Laboratorio de Inmunología, Cátedra de Inmunología. Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, 3000 Santa Fe, Argentina.
- Laboratorio de Inmunología, Cátedra de Inmunología. Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, 3000 Santa Fe, Argentina.
- Laboratorio de Inmunología, Cátedra de Inmunología. Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, 3000 Santa Fe, Argentina.
- Cátedra de Infectología, Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Padre Kredder 2805, 3080 Esperanza, Argentina.
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
- Laboratorio de Diagnóstico e Investigaciones Agropecuarias, Sub- Dirección de Ganadería y Sanidad Animal, Ministerio de la Producción de la Provincia de Santa Fe, Boulevard Pellegrini 3100, 3000 Santa Fe, Argentina; Laboratorio de Inmunología, Cátedra de Inmunología. Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, 3000 Santa Fe, Argentina. Electronic address: soutullo@fbcb.unl.edu.ar.
MeSH Terms
- Animals
- Antibodies, Viral / blood
- Argentina / epidemiology
- Base Sequence
- DNA, Viral / blood
- DNA, Viral / genetics
- Epidemiological Monitoring / veterinary
- Equine Infectious Anemia / blood
- Equine Infectious Anemia / epidemiology
- Genes, env / genetics
- Horses
- Immunity, Cellular / immunology
- Infectious Anemia Virus, Equine / classification
- Infectious Anemia Virus, Equine / genetics
- Infectious Anemia Virus, Equine / immunology
- Mesterolone / blood
- Molecular Sequence Data
- Phylogeny
- Sequence Alignment
- Viral Envelope Proteins / genetics
Citations
This article has been cited 4 times.- Hu Z, Guo K, Du C, Sun J, Naletoski I, Chu X, Lin Y, Wang X, Barrandeguy M, Samuel M, Wang W, Lau PI, Wernery U, Raghavan R, Wang X. Development and evaluation of a blocking ELISA for serological diagnosis of equine infectious anemia.. Appl Microbiol Biotechnol 2023 May;107(10):3305-3317.
- Câmara RJF, Bueno BL, Resende CF, Balasuriya UBR, Sakamoto SM, Reis JKPD. Viral Diseases that Affect Donkeys and Mules.. Animals (Basel) 2020 Nov 25;10(12).
- Malossi CD, Fioratti EG, Cardoso JF, Magro AJ, Kroon EG, Aguiar DM, Borges AMCM, Nogueira MF, Ullmann LS, Araujo JP Jr. High Genomic Variability in Equine Infectious Anemia Virus Obtained from Naturally Infected Horses in Pantanal, Brazil: An Endemic Region Case.. Viruses 2020 Feb 12;12(2).
- Alnaeem AA, Hemida MG. Surveillance of the equine infectious anemia virus in Eastern and Central Saudi Arabia during 2014-2016.. Vet World 2019 May;12(5):719-723.
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