Efficacy and safety of a modified-live cyprinid herpesvirus 3 vaccine in koi (Cyprinus carpio koi) for prevention of koi herpesvirus disease

• E. P. Scott ^[1] ; Kirsten ^[2] ; Susan ^[3] ; Lori ^[4] ; Philip ^[5] ; Gary ^[6] ; Kira ^[7] ; Arnon ^[8]
  1. [1] Weber
  2. [2] V. Malm
  3. [3] C. Yun
  4. [4] A. Campbell
  5. [5] H. Kass
  6. [6] D. Marty
  7. [7] Salonius
  8. [8] Dishon

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• Localización: American Journal of Veterinary Research, ISSN-e 1943-5681, ISSN 0002-9645, Vol. 75, Nº. 10, 2014, págs. 899-904
• Idioma: inglés
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  • Objective—To investigate safety and efficacy of a cyprinid herpesvirus type 3 (CyHV3) modified-live virus vaccine for the prevention of koi herpesvirus disease (KHVd).

    Animals—420 healthy koi (Cyprinus carpio koi).

    Procedures—Fish were vaccinated with a 1× dose or 10× overdose of CyHV3 modified-live virus vaccine or a placebo through bath exposure in tanks at 22°C. Horizontal transmission of vaccine virus was evaluated by commingling unvaccinated and vaccinated fish. Efficacy was evaluated by challenge exposure of vaccinated and naïve fish to a wild-type virus. Fish that died were submitted for quantitative PCR assay for CyHV3 and histologic evaluation.

    Results—The CyHV3 vaccine was safe and efficacious, even at a 10× overdose. Vaccine-associated mortality rate was inversely associated with body weight, with a cumulative mortality rate of 9.4% (18/192) in fish weighing ≤ 87 g and no deaths in fish weighing > 87 g (0/48). Horizontal transfer of vaccine virus from vaccinates to naïve fish was negligible. For efficacy, the vaccine provided a significant reduction in mortality rate after challenge exposure to a wild-type virus, with a prevented fraction of 0.83 versus the placebo control fish.

    Conclusions and Clinical Relevance—KHVd is highly contagious and commonly leads to deaths in 80% to 100% of exposed fish, representing a major threat to koi and common carp populations throughout the world. The CyHV3 modified-live virus vaccine had a favorable safety profile and was an effective vaccine for the control of KHVd in koi weighing > 87 g.