Efficacy of DNA Vaccines in Protecting Rainbow Trout against VHS and IHN under Intensive Farming Conditions
Andrea Marsella,
Francesco Pascoli,
Tobia Pretto,
Alessandra Buratin,
Lorena Biasini,
Miriam Abbadi,
Luana Cortinovis,
Paola Berto,
Amedeo Manfrin,
Marco Vanelli,
Simona Perulli,
Jesper S. Rasmussen,
Dagoberto Sepúlveda,
Niccolò Vendramin,
Niels Lorenzen,
Anna Toffan
Affiliations
Andrea Marsella
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Francesco Pascoli
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Tobia Pretto
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Alessandra Buratin
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Lorena Biasini
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Miriam Abbadi
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Luana Cortinovis
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Paola Berto
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Amedeo Manfrin
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Marco Vanelli
FATRO S.p.A., 40064 Ozzano dell’Emilia, Italy
Simona Perulli
FATRO S.p.A., 40064 Ozzano dell’Emilia, Italy
Jesper S. Rasmussen
Unit for Fish and Shellfish Diseases, Institute for Aquatic Resources, Technical University of Denmark, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
Dagoberto Sepúlveda
Unit for Fish and Shellfish Diseases, Institute for Aquatic Resources, Technical University of Denmark, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
Niccolò Vendramin
Unit for Fish and Shellfish Diseases, Institute for Aquatic Resources, Technical University of Denmark, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
Niels Lorenzen
Unit for Fish and Shellfish Diseases, Institute for Aquatic Resources, Technical University of Denmark, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
Anna Toffan
Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory for Fish Diseases, 35020 Legnaro, Italy
Despite the negative impact of viral hemorrhagic septicemia (VHS) and infectious hematopoietic necrosis (IHN) on European rainbow trout farming, no vaccines are commercially available in Europe. DNA vaccines are protective under experimental conditions, but testing under intensive farming conditions remains uninvestigated. Two DNA vaccines encoding the glycoproteins (G) of recent Italian VHSV and IHNV isolates were developed and tested for potency and safety under experimental conditions. Subsequently, a field vaccination trial was initiated at a disease-free hatchery. The fish were injected intramuscularly with either the VHS DNA vaccine or with a mix of VHS and IHN DNA vaccines at a dose of 1 µg/vaccine/fish, or with PBS. At 60 days post-vaccination, fish were moved to a VHSV and IHNV infected facility. Mortality started 7 days later, initially due to VHS. After 3 months, IHN became the dominant cause of disease. Accordingly, both DNA vaccinated groups displayed lower losses compared to the PBS group during the first three months, while the VHS/IHN vaccinated group subsequently had the lowest mortality. A later outbreak of ERM caused equal disease in all groups. The trial confirmed the DNA vaccines to be safe and efficient in reducing the impact of VHS and IHN in farmed rainbow trout.