November 2018

Signalment (JPC #1523819):  A sheep


HISTOPATHOLOGIC DESCRIPTION:  Tongue:  Multifocally epithelium is eroded and ulcerated and replaced by a thick serocellular crust composed of numerous viable and degenerate neutrophils, necrotic cellular debris, fibrin and hemorrhage.  Adjacent epithelium is multifocally hyperplastic with acanthosis,  prominent intercellular bridging (spongiosus) and variably sized, but often large, intracytoplasmic clear vacuoles (hydropic degeneration) that compress nuclei.  Within the affected epithelium, there are variably sized clefts filled with degenerate neutrophils, fibrin, and hemorrhage (hemorrhagic pustules).  The submucosa is expanded by moderate number of macrophages, neutrophils, with fewer lymphocytes and plasma cells, fibrin, edema, and abundant hemorrhage that surrounds vessels and separate collagen and skeletal muscle bundles.  Multifocally within vessels  endothelial cells are hypertrophic with enlaged vesiculate nuclei (reactive), shrunken with hypereosinophilic cytoplasm and pyknotic nuclei (necrosis) or lost and the walls are expanded by small amounts of edema and fibrin (vasculitis).  Multifocally lingual salivary glands adjacent to areas of inflammation are shrunken and atrophic and/or acinar cells are hypertrophic and vacuolated (degeneration), and there are ectatic ducts and infiltration with low numbers of lymphocytes, plasma cells and few histiocytes. Multifocally, striated muscle cells are distended by oval to elongate protozoal cysts (70-500 um), containing numerous tightly packed, deeply basophilic, crescent-shaped bradyzoites (7-20um).


  1. Tongue:  Glossitis, ulcerative, subacute, multifocal, moderate, with hemorrhagic pustules, fibrinoid vasculitis, subepithelial hemorrhage and edema, breed unspecified, ovine.
  2. Tongue, skeletal muscle: Intramuscular protozoal cysts, multiple, etiology consistent with Sarcocystis sp. 

ETIOLOGY:  Ovine orbivirus

ETIOLOGIC DIAGNOSIS:  Orbiviral glossitis

CONDITION:  Bluetongue








For erosive and ulcerative stomatitis/glossitis in sheep:

In cattle consider the following differential diagnoses:

White-tailed deer and mule deer:


Other common Orbiviruses:


  1. Allen AJ, Stanton JB, Evermann JF, et al. Bluetongue disease and seroprevalence in South American camelids from the northwestern region of the United States.  J Vet Diagn Invest. 2015;27(2):226-230.
  2. Cantile C, Youssef S. Nervous System. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St Louis, MO: Elsevier; 2016: 281.
  3. Enserink M. Exotic disease of farm animals tests Europe’s responses. Science. 2008;319:710-711.
  4. Hemati B, Contreras V, Uien C, et al. Bluetongue virus targets conventional dendritic cells in skin lymph. J Virol. 2009;83(17):8789-8799.
  5. Kienzle C, Poulson RL, Ruder MG, et al. Virus Isolation and Molecular Detection of Bluetongue and Epizootic Hemorrhagic Disease Viruses from Naturally Infected White-tailed Deer (Odocoileus Virginianus) on St. John, US Virgin Islands. Wildl Dis. 2017; 53(4):843-849.
  6. MacLachlan NJ, Crafford JE, Vernau W, et al. Experimental reproduction of severe bluetongue in sheep. Vet Pathol. 2008;45:310-315.
  7. MacLachlan NJ, Drew CP, Karpel KE, Worwa G. The pathology and pathogenesis of bluetonque. J Comp Path 2009;141b:1-16.
  8. Murphy F, Gibbs P, Horzinek M, et al. Veterinary Virology. San Diego, CA: Academic Press;1999:398-400.
  9. Ortega J, Crossley B, Dechant JE, Drew CP, MacLachlan NJ. Fatal bluetongue virus infection in an Alpaca (Vicugna Pacos) in California.  J Vet Diagn Invest. 2010;22:134.
  10. Reuter JD, Nelson SL. Hematologic Parameters and Viral Status for Zika, Chikungunya, Bluetongue, and Epizootic Hemorrhagic Disease in White-tailed Deer. Wildl Dis. 2018; 54(4):843-847.
  11. Ruder MG, Johnson D, Ostlund E, et al. The First 10 Years (2006–15) of Epizootic Hemorrhagic Disease Virus Serotype 6 in the USA. Wildl. Dis. 2017; 53(4):843-849.
  12. Ruder MG, Stallknecht DE, Allison AB, et al. Host and potential vector susceptibility to an emerging orbivirus in the United States: Epizootic hemorrhagic disease virus serotype 6. Wildl. Dis. 2017; 53(4):901-905.
  13. Schlafer DH, Foster RA. Female Genital System. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St Louis, MO: Elsevier; 2016: 431.
  14. Uzal FA, Platter BL, Hostetter JM. Alimentary System. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St Louis, MO: Elsevier; 2016: 136-139, 145-146.
  15. Valentine BA. Skeletal Muscle. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:923.
  16. Zachary JF. Mechanisms of Microbial Infections. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:214.

Click the slide to view.

Click on image for diagnostic series.

Back | Home | Contact Us | Links | Help |