ISSN 2398-2977      

Theiler's disease-associated virus


Synonym(s): TDAV




  • A single-stranded RNA virus.
  • Family: Flaviviridae.
  • Genus:Pegivirus.

Clinical Effects



  • Chronic carriers exist and may serve as reservoir of the virus.


  • Infection occurs by blood transmission and within a year 75% of horses have cleared the virus.
  • Those that are chronically infected maintain similar degrees of viremia as were found initially.


  • Blood products: when it occurs, Theiler's disease is most commonly seen 4-10 weeks after administration of blood product.
  • There is no evidence of horizontal transmission based upon data from a single study location.

Pathological effects


Other countermeasures

  • Equine serum and plasma products could be checked for presence of the virus.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Drexler J F (2013) Evidence for novel hepaciviruses in rodents. PLoS Pathog (6), e1003438 PubMed
  • Kapoor A et al (2013) Identification of a pegivirus (GB virus-like virus) that infects horses. J Virol 87 (12), 7185-7190 PubMed.
  • Chandriani S et al (2013) Identification of a previously undescribed divergent virus from the flaviviridae family in an outbreak of equine serum hepatitis. Proc Natl Acad Sci 110 (15), E1407-E1415 PubMed.
  • Burbelo P D et al (2012) Serology-enabled discovery of genetically diverse hepaciviruses in a new host. J Virol 86 (11), 6171-6178 PubMed.
  • Lyons S et al (2012) Nonprimate hepaciviruses in domestic horses, United kingdom. Emerg Infect Dis 18 (12), 1976-1982. doi: 10.3201/eid1812.120498 PubMed.

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