Epstein-Barr virus

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Immunohistochemical slide of EBV within canine bone marrow cells[1]
Circulating lymphocyte staining for EBV virus presence.[1]

Epstein-Barr virus (EBV) is a γ-herpesvirus (lymphocryptovirus) which infects humans and causes glandular fever (infectious mononucleosis), Burkitt's lymphoma and nasopharyngeal carcinoma[2].

In humans, EBV expresses proteins containing numerous short pentapeptides identical to those found in multiple sclerosis autoantigens[3], a disease which has been linked epidemiologically with humans in close contact with dogs, sheep or cattle. A link between human MS and canine distemper virus has already been postulated[4]

EBV produces membrane proteins (intrabodies; latent membrane protein 1), essential to EBV-induced human B cell immortalization[5].

Dogs are commonly exposed to this virus via aerosol transmission from humans, but rarely develop symptoms associated with viremia. Routine epidemiological surveys report EBV positive dogs in up to 80% of cases[6].

Seroprevalence of exposure to the virus in dogs has been reported commonly across the world[1], but zoonotic spread of EBV from dogs to humans is unlikely.

In most cases of canine infection with EBV, mild pharyngitis and tonsillitis may be observed, associated with viral proliferation in pharyngeal tonsil. Although there is no evidence of EBV in canine peripheral blood mononuclear cells[1], EBV-like virus infection has been detected frequently in the peripheral blood of pet dogs[1]. Moreover, as EBV-specific antigens are expressed during the early stage of virus infection, the presence of strong antibody signals to these EBV antigens indicated that some dogs could be experiencing virus reactivation[7]. The presence of EBER in bone-marrow cells and peripheral lymphocytes (see figure right) further indicate that an EBV-like virus infection could be latent in some dogs.

However, recent researched has alluded to the development of malignant lymph nodes of dogs with lymphoma associated with EBV, underlying the role of this virus in neoplasia as is observed with humans[8].

Diagnosis is based on PCR identification of the virus on tonsillar swabs.

References

  1. 1.0 1.1 1.2 1.3 1.4 Milman G et al (2011) Serological detection of Epstein-Barr virus infection in dogs and cats. Vet Microbiol 150(1-2):15-20
  2. Yang L et al (2000) CD21-mediated entry and stable infection by Epstein-Barr virus in canine and rat cells. J Virol 74(22):10745-10751
  3. Carter CJ (2012) Epstein-Barr and other viral mimicry of autoantigens, myelin and vitamin D-related proteins and of EIF2B, the cause of vanishing white matter disease: massive mimicry of multiple sclerosis relevant proteins by the Synechococcus phage. Immunopharmacol Immunotoxicol 34(1):21-35
  4. Lincoln JA et al (2008) Could Epstein-Barr virus or canine distemper virus cause multiple sclerosis? Neurol Clin 26(3):699-715
  5. Fang CY et al (2007) Modulation of Epstein-Barr virus latent membrane protein 1 activity by intrabodies. Intervirology 50(4):254-263
  6. Chiou SH et al (2005) Discovery of Epstein-Barr virus (EBV)-encoded RNA signal and EBV nuclear antigen leader protein DNA sequence in pet dogs. J Gen Virol 86(4):899-905
  7. de Turenne-Tessier, M et al (1986) Characterization of an Epstein-Barr virus-induced thymidine kinase. J Virol 57:1105–1112
  8. Huang SH et al (2012) Evidence of an oncogenic gammaherpesvirus in domestic dogs. Virology 427(2):107-117