LAUSR

VACCINATION has advanced as a control measure to protect zoo bird populations from highly pathogenic avian influenza (HPAI) outbreaks (Ellis and others 2004; European Commission 2006; United States Department of Agriculture, Animal and Plant Health Inspection Service 2016). In 2005 through 2007, European zoos implemented preventive HPAI vaccination protocols of their bird populations, which elicited strong although heterogeneous responses in zoo birds in the months following vaccination (Philippa and others 2007; Bertelsen and others 2007; Furger and others 2008; Lecu and others 2009; Vergara-Alert and others 2011). Many zoo birds, including most of those birds targeted by the vaccination programmes, have lifespans in excess of 20 years. Therefore, the longevity of the vaccine-induced immune responses is critical for accurately assessing the risk of HPAI among vaccinated flocks, as well as designing effective and efficient vaccination protocols. However, very little information on the longevity of HPAI immunity is available. We have recently published evidence for highly prevalent, strong vaccine-induced immune responses to H5 avian influenza virus (AIV) in flamingos ( Phoenicopterus species) seven years after vaccination (Fernandez-Bellon and others 2016). The present study aims to investigate whether non-Phoenicopteriformes birds also present sustained antibody responses to H5 AIV seven years after vaccination. This study was performed on opportunistic samples from birds housed at Barcelona Zoo (BZ) in 2014, which had been vaccinated against H5 HPAI in 2006 and 2007 (Vergara-Alert and others 2011). Table 1 shows the species and number of birds studied. Briefly, the birds were vaccinated, and revaccinated four weeks later, in spring 2006 by intramuscular injection …