Efficacy of a deletion mutant bovine herpesvirus-1 (BHV-1) vaccine that allows serologic differentiation of vaccinated from naturally infected animals.
Fifteen bovine herpesvirus-1 (BHV-1)-negative calves were vaccinated intramuscularly with 10(7.4) plaque-forming units of a double-deletion BHV-1 mutant (IBRV(NG)dltkdlgIII), and 6 remained as nonvaccinated controls. Thirty days after vaccination, the animals were challenged by nasal instillation of 10(8.2) CCID50 of a virulent BHV-1 strain (Cooper). The vaccinated calves were protected against wildtype virus challenge as demonstrated by clinical evaluation. Most of the vaccinates developed only a mild rhinitis (lasting an average of 6.5 days) with almost no systemic symptoms, whereas the controls developed a serious illness characterized by rhinitis (mean = 11.5 days), conjunctivitis, hyperthermia, apathy, loss of appetite, and dyspnea. The vaccinates also shed significantly less virus and for a shorter period of time (mean = 5.5 days) than the controls (mean = 9 days). Thirty days after vaccination, the vaccinates were negative in an anti-gIII specific blocking enzyme-linked immunosorbent assay (ELISA), despite the fact that most of them had developed neutralizing antibodies (serum neutralization titers ranging from 1:2 to 1:16). Seroconversion to gIII was detected as early as 7 days postinfection (dpi). Fourteen days after the challenge, all the animals exposed to wildtype BHV-1 had developed anti-gIII antibodies and were positive in this differential serologic test. Six controls plus 8 vaccinates kept in isolation were still positive to gIII when tested at 75 dpi. The use of the IBRV(NG)dltkdlgIII strain in conjunction with an anti-gIII specific blocking ELISA kit represents a powerful tool for BHV-1 control/eradication programs.
Flores
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Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln 68583.
Osorio
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FA
Zanella
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EL
Kit
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S
Kit
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M
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001831:Body Temperature; D002417:Cattle; D002418:Cattle Diseases; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006561:Herpes Simplex / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D001911:Herpesvirus 2, Bovine / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D007114:Immunization / Q000662:veterinary*; D009500:Neutralization Tests / Q000662:veterinary; D017384:Sequence Deletion; D013997:Time Factors; D014614:Vaccines, Synthetic / Q000627:therapeutic use*; D014765:Viral Vaccines / Q000627:therapeutic use*; D017201:Virus Shedding
D000914:Antibodies, Viral; D014614:Vaccines, Synthetic; D014765:Viral Vaccines