William G. Starkey

The susceptibility of Atlantic salmon fry to freshwater infectious pancreatic necrosis is largely explained by a major QTL

Infectious pancreatic necrosis (IPN) is a viral disease with a significant negative impact on the global aquaculture of Atlantic salmon. IPN outbreaks can occur during specific windows of both the freshwater and seawater stages of the salmon life cycle. Previous research has shown that a proportion of the variation seen in resistance to IPN is because of host genetics, and we have shown that major quantitative trait loci (QTL) affect IPN resistance at the seawater stage of production. In the current study, we completed a large freshwater IPN challenge experiment to allow us to undertake a thorough investigation of the genetic basis of resistance to IPN in salmon fry, with a focus on previously identified QTL regions. The heritability of freshwater IPN resistance was estimated to be 0.26 on the observed scale and 0.55 on the underlying scale. Our results suggest that a single QTL on linkage group 21 explains almost all the genetic variation in IPN mortality under our experimental conditions. A striking contrast in mortality is seen between fry classified as homozygous susceptible versus homozygous resistant, with QTL-resistant fish showing virtually complete resistance to IPN mortality. The findings highlight the importance of the major QTL in the genetic regulation of IPN resistance across distinct physiological lifecycle stages, environmental conditions and viral isolates. These results have clear scientific and practical implications for the control of IPN.

Phylogenetic and antigenic characterization of new fish nodavirus isolates from Europe and Asia

Nodaviruses are widespread causative agents of viral nervous necrosis in fish. Based on the coat protein sequence, fish nodaviruses are categorized into four different genotypes. In this study, we present data on the phylogenetic and antigenic characterization of 12 new isolates, eight European and four of Asian origin, from farmed and wild species of fish. Phylogenetic analysis based on the nucleotide sequence (688 bases) of the coat protein classified the majority of these new isolates to the RGNNV genotype. Geographic or host-species specificities were not revealed by this study. Neutralizing assay experiments, further confirmed the genotypic classification, supporting the possibility that the different nodavirus genotypes can also be serologically distinguishable.

Nodavirus infection in Atlantic cod and Dover sole in the UK

E. (1992) Pathological changes in kidneys of dogs with natural Leishmania infection. Veterinary Parasitology 45, 33-47 POLI, A., ABRAMO, F., MANCIANTI, F., NIGRO, M., PIERI, S. & BIONDA, A. (1991) Renal involvement in canine leishmaniasis. Nephronl 57,444-452 PUMAROLA, M., BREVIK, L., BADIOLA, J., VARGAS, A., DOMINGO, M. & FERRER, L. (1991) Canine leishmaniasis associated with systemic vasculitis in two dogs. Journal of Comparative Pathology 105, 279-286 REAGAN, W. J. & REBAR, A. H. (1995) Platelet disorders. In Textbook of Veterinary Internal Medicine. Philadelphia, W. B. Saunders. pp 1964-1976 SAINZ, A., TESOURO, M. A., RODRIGUEZ, F., MAYORAL, I. & MAZZUCHELLI, F. (1995) Seroprevalence of Ehrlichia canis infections in police dogs in Spain. Preventive Veterinary Medicine 23, 179-182 SLAPPENDEL, R. J. (1988) Canine leishmaniasis. A review based on 95 cases in the Netherlands. Veterinary Quarterly 10, 1-16 SLAPPENDEL, R. J. (1989) Disseminated intravascular coagulation. In Kirks Current Veterinary Therapy X. Small Animal Practice. Philadelphia, W. B. Saunders. pp 451-457 SLAPPENDEL, R. J. & FERRER, L. (1998) Leishmaniasis. In Infectious Diseases of the Dog and Cat. Philadelphia, W. B. Saunders. pp 450-458 SLAPPENDEL, R. J., FRIELINK, R. A., MOL, J. A., NOORDZIJ, A. & HAMER, R. (1992) An enzyme-linked immunosorbent assay (ELISA) for von Willebrand factor antigen (vWf-Ag) in canine plasma. Veterinary Immunology and Immunopathology 33, 145-154 TABOADA, J. & MERCHANT, S. R. (1995) Protozoal and miscellaneous infections. In Textbook of Veterinary Internal Medicine. Philadelphia, W. B. Saunders. pp 384-397 TESOURO, M. A. (1984) Aspectos clinicos y laboratoriales de la leishmaniosis canina. Estudio epizootiologico en la provincia de Madrid. PhD thesis, Universidad Comlutense de Madrid, Madrid TESOURO, M. A., RODRIGUEZ, F., SAINZ, A. & JIMENEZ, F. (1992) Contribuciones al diagnostico y patocronia de la leishmaniosis canina (I). Informacion Veterinaria 125,40-46 VALLADARES, J. E., RUIZ DE GOPEGUI, R., RIERA, C., ALBEROLA, J., GALLEGO, M., ESPADA, Y., PORTUS, M. & ARBOIX, M. (1998) Study of haemostatic disorders in experimentally induced leishmaniasis in Beagle dogs. Research in Veterinary Science 64, 195-198 VARELA, F. (1992) Immunopatologia de la leishmaniosis canina: bases teoricas y aspectos practico. Premios Fundacion Purina, Columna Ediciones SA. pp11 -54 WARDROP, K. J., DHEIN, C. R., FRENIER, S. & MEYERS, K. M. (1989) Altered hemostasis in a dog with chronic renal failure. Journal oftheAmerican Animal Hospital Association 25, 325-329 WERNER, L. L., TURNWALD, G. H. & BARTA, 0. (1994) Immunologic and plasma protein disorders. In Small Animal Clinical Diagnosis by Laboratory Methods. Philadelphia, W. B. Saunders. pp 253-272 WILLIS, S. E., JACKSON, M. L., MERIC, S. M. & ROUSSEAUX, C. G. (1989) Whole blood platelet aggregation in dogs with liver disease. American Journal of Veterinary Research 50, 1893-1897

Identification of B-cell epitopes on the betanodavirus capsid protein

Abstract The pepscan procedure was used to identify betanodavirus B‐cell epitopes recognized by neutralizing mouse monoclonal antibodies (MAbs) and serum samples obtained from sea bass, Dicentrarchus labrax, naturally infected with betanodavirus. Pepscan was performed with a panel of thirty‐four 12‐mer synthetic peptides that mimicked the entire betanodavirus capsid protein. Sea bass serum samples reacted strongly with three regions of the capsid protein comprising amino acid residues 1–32, 91–162 and 181–212. The latter region was also recognized by neutralizing MAbs and coincided with a region of high antigenic propensity identified by an antigen prediction algorithm. These data suggest that a region of the betanodavirus capsid protein spanning amino acid residues 181–212 may represent a neutralization domain that could potentially be used to inform the development of nodavirus vaccines and immunodiagnostic reagents.