Conventional inactivated bivalent H5/H7 vaccine prevents viral localisation in muscles of turkeys infected experimentally with LPAI and HPAI H7N1 isolates

Anna Toffan (1) , Maria Serena Beato (1) , Roberta de Nardi (1) , Elena Bertoli (1) , Annalisa Salviato (1) , Giovanni Cattoli (1) , Calogero Terregino (2) , Ilaria Capua (1)

1 OIE/FAO and National reference laboratory for Avian Influenza and Newcastle Disease
2 Virology laboratory

Highly Pathogenic Avian Influenza (HPAI) viruses cause viraemia and systemic infections with virus replication in internal organs and muscles, in contrast Low Pathogenicity Avian Influenza (LPAI) viruses produce mild infections with low mortality rates and local virus replication. There is little available information on the ability of LPAI viruses to cause viraemia or on the presence of AI viruses in general in the muscles of infected turkeys. The aim of this study was to determine the ability of LPAI and HPAI H7N1 viruses to reach muscle tissues following experimental infection and the efficacy of vaccination in preventing viraemia and meat localisation. The potential of infective muscle tissue to act as a source of infection for susceptible turkeys by mimicking the practice of swill-feeding was also investigated. The HPAI virus was isolated from blood and muscle tissues of all unvaccinated turkeys, LPAI could be isolated only from blood of one bird and could be detected only by RT-PCR in muscles. In contrast, in vaccinated/challenged turkeys, no viable virus or viral RNA could be detected in muscles indicating that in vaccinated birds viral localisation in muscle tissue is prevented.

Mots clés: Life Sciences

Anna Toffan, Maria Serena Beato, Roberta de Nardi, Elena Bertoli, Annalisa Salviato, et al.. Conventional inactivated bivalent H5/H7 vaccine prevents viral localisation in muscles of turkeys infected experimentally with LPAI and HPAI H7N1 isolates. Avian Pathology, 2008, 37 (04), pp.407-412. ⟨10.1080/03079450802061124⟩. ⟨hal-00540117⟩