Pathology in Practice

Rebecca E. Ruby 1Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.

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Set Sokol 1Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.

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Gerald E. Duhamel 1Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.

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History

A 7.8-kg (17.16-lb) Holstein bull fetus at approximately 195 days of gestation with a crown-to-rump length of 57 cm was submitted for necropsy. The cow had no history of prior disease or reported periparturient clinical abnormalities, and no other recent abortions in the herd were reported. The herd's vaccination history was not available. No fetal membrane tissue was submitted for examination.

Clinical and Gross Findings

At necropsy, gross findings included hundreds of white to tan, randomly distributed, round (≤ 2-mm-diameter) foci distributed throughout the dermis (Figure 1). Similar white foci were present on the pleural surface, throughout the parenchyma of all lung lobes, and on both the serosal and mucosal surfaces of all 4 compartments of the stomach. The lung lobes were mildly edematous with expansion of the intralobular septae by edema.

Figure 1—
Figure 1—

Photographs of the skin covering the outer thigh muscles (A) and a portion of the lungs (B) of an aborted Holstein bull fetus. The duration of gestation was approximately 195 days. Notice the multifocal white-gray, 1- to 2-mm-diameter foci randomly scattered throughout the dermis. The lungs have moderate intralobular expansion by edema fluid and similar white-gray foci.

Citation: Journal of the American Veterinary Medical Association 255, 5; 10.2460/javma.255.5.543

Formulate differential diagnoses from the history, clinical findings, and Figure 1—then turn the page→

Histopathologic and Laboratory Findings

Microscopic examination of sections of the liver, lungs, kidneys, abomasum, and skin revealed randomly scattered foci of necrosis; there were rare intranuclear eosinophilic inclusion bodies in sections of the liver and kidneys. Large numbers of brightly eosinophilic, rounded, necrotic hepatocytes that contained small amounts of cytoplasmic mineral were present. Within the lung tissue, there were randomly distributed multifocal areas of necrosis and moderate amounts of edema and fibrin within alveolar spaces (Figure 2).

Figure 2—
Figure 2—

Photomicrographs of sections of affected lung and skin tissues obtained from the aborted fetus in Figure 1. A—The lung tissue has multifocal necrosis and accumulation of cellular debris. H&E stain; bar = 200 μm. B—Following immunohistochemical analysis for bovine herpesvirus-1, the lung tissue has strong, diffuse immunopositivity (red staining) within areas of necrosis. Bovine herpesvirus-1-specific stain with 3,3′-diaminobenzidine; bar = 500 μm. C—Following immunohistochemical analysis for bovine herpesvirus-1, the skin tissue has strong, diffuse immunopositivity. Bovine herpesvirus-1-specific stain with 3,3′-diaminobenzidine; bar = 100 μm.

Citation: Journal of the American Veterinary Medical Association 255, 5; 10.2460/javma.255.5.543

Immunohistochemical analysis for bovine herpesvirus-1 (BoHV-1) was performed on sections of the intestines, lungs, and skin. There was strong cytoplasmic and membranous immunopositivity for BoHV-1 within the necrotic epithelial cells of the lungs and skin (Figure 2). Sections of the intestines had no BoHV-1 immunoreactivity. A fluorescent antibody test for bovine herpesviral antigen that used a monoclonal antibody against BoHV-1 glycoprotein C was performed on fresh samples of the fetal brain. The test result was positive. Results of fluorescent antibody tests run on pooled samples of lung, kidney, and spleen tissue for bovine viral diarrhea virus, Campylobacter fetus, and Leptospira spp were negative. Aerobic bacterial culture of samples of the abomasal contents or lung tissue yielded no growth of pathogenic organisms. The results of fungal culture of skin samples were negative.

Morphologic Diagnosis and Case Summary

Morphologic diagnosis: multifocal hepatic, pulmonary, renal, abomasal, and dermal necrosis with rare intranuclear eosinophilic viral inclusions attributable to BoHV-1.

Case summary: systemic infection with BoHV-1 in an aborted bull fetus.

Comments

On the basis of the gross findings of white foci throughout multiple organs in the aborted fetus of the present report, a systemic infection was suspected. Top differential diagnoses included fungal (eg, Aspergillus spp), bacterial (eg, Staphylococcus spp), or viral (BoHV-1) infection. In the case described in the present report, results of a fluorescent antibody test for bovine herpesviral antigen and immunohistochemical analysis for BoHV-1 and the presence of typical lesions of multifocal necrosis with intranuclear inclusion bodies confirmed a diagnosis of in utero BoHV-1 infection of the fetus. Of particular interest in this case were the numerous foci of dermal necrosis, which corresponded with areas of BoHV-1 immunoreactivity. Dermal lesions in aborted calves classically are fungal plaques or caused by infection with bacteria or, rarely, BoHV-1.1–3 For these reasons, bacterial and fungal cultures of affected tissues were performed to rule out bacterial or fungal infection. In general, BoHV-1-induced abortion can be confirmed by results of viral isolation procedures, immunofluorescent antibody testing, or PCR assay performed on appropriate specimens or immunohistochemical analysis of formalin-fixed tissues.

Bovine herpesvirus-1 is an alphaherpesvirus with worldwide distribution. Bovine herpesvirus-1 is the etiologic agent of infectious bovine rhinotracheitis, which can establish latent infection within the trigeminal ganglia.4 Transmission between animals may occur via aerosolization, direct contact, reproductive activity, or fomites. The clinical signs that infected cattle develop vary depending on the animals' age. In breeding cows and bulls, the virus can cause vulvovaginitis and balanoposthitis. Feedlot calves with BoHV-1 infection may develop pneumonia and keratoconjutivitis.3,4 Calves that are infected in utero may be aborted or may develop systemic disease in the first month after birth. Both the field strain and vaccine strain of BoHV-1 are reported to cause abortion in pregnant cows 2 weeks to 2 months following exposure.5–7 In cattle herds, abortions may occur as either abortion storms or sporadic events and are most common in the fifth to eighth month of pregnancy. An infected cow commonly remains systemically healthy; the fetus is aborted 4 to 7 days following death in utero.5–8 Fetal infection is thought to occur via hematogenous spread through the umbilical vein,9 but it has been suggested that the virus passes though the endothelium to the interstitium of the villus of the caruncle and then infects the endothelium of the cotyledon followed by the trophoblast. Fetal death is a result of tissue necrosis, and fetuses are usually expelled in an advanced state of autolysis.10

In cases of BoHV-1-induced abortion, gross lesions in the fetus are considered rare and, in large part, attributable to autolysis. Reported gross lesions have included multifocal white to tan foci under the liver capsule and on the surface of the lungs as well as renal hemorrhage. Pulmonary lobular edema has been observed in several aborted fetuses.8 A single report of white focal lesions in fetal skin, which corresponded with focal areas of necrosis microscopically, was mentioned in a review of BoHV-1 abortions in cattle.8

Microscopically, foci of necrosis are seen in many tissues including the liver, adrenal glands, kidneys, intestines, lymph nodes, lungs, and spleen of bovine fetuses aborted as a result of infection of the dams with BoHV-1. Inclusion bodies are typically difficult to identify in aborted calves. Necrotizing vasculitis, secondary to endothelial cell infection, in the placenta may be observed in some fetuses. Encephalitis has also been identified in aborted bovine fetuses infected with BoHV-1.4 The case of BoHV-1-induced abortion of a bull fetus described in the present report has highlighted the fact that grossly apparent, multifocal, dermal necrosis may be present in addition to the more common finding of necrosis within multiple internal organs.

Acknowledgments

No external funding was used in the research, authorship, or publication of this article. The authors declare that there were no conflicts of interest.

References

  • 1. Corbellini LG, Pescador CA, Frantz FJ, et al. Staphylococcus spp. abortion: skin lesions caused by Staphylococcus aureus infection in an aborted bovine-fetus. Vet Res Commun 2006;30:717721.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2. Kirkbride CA. Etiologic agents detected in a 10-year study of bovine abortions and stillbirths. J Vet Diagn Invest 1992;4:175180.

  • 3. Kennedy PC, Richards WPC. The pathology of abortion caused by the virus of infectious bovine rhinotracheitis. Pathol Vet 1964;1:717.

    • Search Google Scholar
    • Export Citation
  • 4. Brower A, Homb KM, Bochsler P, et al. Encephalitis in aborted bovine fetuses associated with bovine herpesvirus 1 infection. J Vet Diagn Invest 2008;20:297303.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Mitchell D. An outbreak of abortion in a dairy herd following inoculation with an intramuscular infectious bovine rhinotracheitis virus vaccine. Can Vet J 1974;15:148151.

    • Search Google Scholar
    • Export Citation
  • 6. Bryan LA, Fenton RA, Misra V, et al. Fatal, generalized bovine herpesvirus type-1 infection associated with a modified-live infectious bovine rhinotracheitis parainfluenza-3 vaccine administered to neonatal calves. Can Vet J 1994;35:223228.

    • Search Google Scholar
    • Export Citation
  • 7. Rodger SM, Murray J, Underwood JC, et al. Microscopical lesions and antigen distribution in bovine fetal tissues and placentae following experimental infection with bovine herpesvirus-1 during pregnancy. J Comp Pathol 2007;137:94101.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. O'Toole D, Chase CC, Miller MM, et al. Kennedy, the early sixties, and visitation by the angel of death. Vet Pathol 2014;51:10511062.

  • 9. Crook T, Benavides J, Russell G, et al. Bovine herpesvirus 1 abortion current prevalence in the United Kingdom and evidence of hematogenous spread within the fetus in natural cases. J Vet Diagn Invest 2012;24:662670.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Schlafer D, Foster R. Female genital system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer's pathology of domestic animals. 6th ed. St Louis: Mosby, 2016;358564.

    • Search Google Scholar
    • Export Citation
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