Encephalitis Induced by Bovine Herpesvirus 5 and Protection by Prior Vaccination or Infection with Bovine Herpesvirus 1

Abstract

Abstract. Calves were intranasally challenged with bovine herpesvirus 5 (BHV5) and followed for the development of viral infection, clinical encephalitis, histologic lesions in the brain, and viral sequences in the trigeminal ganglia. Calves that were previously vaccinated with bovine herepesvirus 1 (BHV1, n ϭ 4) or previously infected with BHV1 (n ϭ 5) or that had not been exposed to either virus (n ϭ 4) were compared. No calf developed signs of encephalitis, although all calves developed an infection as indicated by nasal secretion of BHV5 and seroconversion to the virus. Histologic lesions of encephalitis consisting of multifocal gliosis and perivascular cuffs of lymphocytes were observed in calves not previously exposed to BHV1. BHV5 sequences were amplified from the trigeminal ganglia of calves previously vaccinated and from calves not previously exposed to BHV1; calves sequentially challenged with BHV1 and later BHV5 had exclusively BHV1 sequences in their trigeminal ganglia. Administration of dexamethasone 28 days after BHV5 challenge did not influence clinical disease or histologic lesions in either previously unexposed calves (n ϭ 2) or previously immunized calves (n ϭ 2), although it did cause recrudescence of BHV5, as detected by nasal virus secretion.Bovine herpesvirus 5 (BHV5) has been isolated from outbreaks of naturally occurring encephalitis 2,4,5,10 and has experimentally induced the same disease. 3,10 The prevalence of this virus is unknown because the disease is sporadic, with only 4 isolations of the virus in various parts of the United States. 1 Determination of the prevalence of this virus as well as the conditions under which it is able to induce disease is important because of the potential for fatal outbreaks of encephalitis in the United States and throughout the world. 2,5,10 Currently, serologic methods cannot distinguish between infections with BHV5 and bovine herpesvirus 1 (BHV1, commonly termed infectious bovine rhinotracheitis virus [IBRV]); 7 thus, isolated viruses must be analyzed using molecular techniques. 1 Because of the close genetic and antigenic relationship between BHV1 and BHV5, prior infection with or vaccination against BHV1 may protect against encephalitis caused by BHV5. The interaction between these 2 viruses, if any, in disease has not been investigated. In addition, the role of latency of BHV1 or BHV5 has not been investigated with respect to disease or protection against encephalitis.A model has been developed to study BHV5-induced encephalitis in 1-2-day-old colostrum-deprived calves. Calves in this model develop a fulminant in- Received for publication February 25, 1998. fection of the brain and exhibit rapidly progressing behavioral changes, leading to terminal recumbency. 3 Although this model works well to study the effects of BHV5 in very young calves, fatal encephalitis in the field is typically seen in calves Ն6 months of age. The present work summarizes the course of an experimental infection with BHV5 in 5-6-month-old calves, both with and without p...

Histopathological, immunohistochemical, and molecular study of BHV-5 infection in the central nervous system of experimentally infected calves

“…Mild or moderate nonsuppurative meningitis has been described in cases of BHV-5 infection in cattle (Lunardi et al 2009), restricted to the anterior and posterior cerebral cortex (Perez et al 2002). However, in previous cases of BHV-5 infection this lesion was not reported (Cascio et al 1999, Colodel et al 2002. Cases of BHV-5 infection with polymorphonuclear infiltration in the brain have been reported (Elias et al 2004, Rissi et al 2006, but this pathological finding was not observed in the present study.…”

Ruminant alphaherpesviruses related to bovine herpesvirus 1

“…Indeed, a primary infection with BoHV-1 affords a cross-protection that protects cattle clinically against BoHV-5 superinfection [13,18]. This feature can explain the epidemiology of BoHV-5 infection in several continents.…”

Caracterização de herpesvírus bovinos tipos 1 (BHV-1) e 5 (BHV-5) com anticorpos monoclonais

“…O BHV-5, por sua vez, parece peculiar em sua distribuição; raras são as amostras de BHV-5 isoladas no hemisfério norte (D'Offay et al 1995, Cascio et al 1999 geográfica, talvez associada a particularidades não identificadas no manejo, tenha levado a que amostras daqueles estados apresentassem maior variabilidade antigênica do que as encontradas nos outros estados. Entretanto, a confirmação desta hipótese terá que aguardar a identificação de um maior número de isolamentos de vírus destas áreas específicas.…”

“…Até o presente, não é possível determinar a real prevalência de infecções por BHV-5, visto que testes sorológicos capazes de distinguir respostas frente a BHV-1 e BHV-5 ainda não se encontram disponí-veis. As infecções pelo BHV-5 são raras no hemisfério norte (D'Offay et al 1995, Cascio et al 1999, diferindo das observações na América do Sul. No Brasil, evidências acumuladas por grupos atuantes na área sugerem que uma significativa proporção de bovinos cujo diagnóstico sorológico havia sido estabelecido como BHV-1 eram provavelmente causadas por BHV-5 (Teixeira et al 1998, Heinlein et al 1993, Weiblen et al 1989.…”