Title: Evaluation of inactivated avian influenza H7 vaccines for protection of chickens against a highly pathogenic avian influenza virus H7N3 isolated from chickens in Jalisco, Mexico, during 2012 Authors
|Ricardez, Yadira -|
|Guzman, Sofia -|
Submitted to: Proceedings of Southern Conference on Avian Diseases
Publication Type: Proceedings
Publication Acceptance Date: November 16, 2012
Publication Date: January 28, 2013
Citation: Kapczynski, D.R., Pantin Jackwood, M.J., Ricardez, Y., Guzman, S., Spackman, E., Suarez, D.L., Swayne, D.E. 2013. Evaluation of inactivated avian influenza H7 vaccines for protection of chickens against a highly pathogenic avian influenza virus H7N3 isolated from chickens in Jalisco, Mexico, during 2012. Proceedings of Southern Conference on Avian Diseases. CDROM. Technical Abstract: A recent outbreak of highly pathogenic avian influenza (HPAI) H7N3 was reported poultry in Jalisco, Mexico, beginning in June of 2012. To date more than 11 million birds have died or been slaughtered in an effort to stop the spread of disease. In response to the outbreak, vaccine efficacy trials were recently performed to determine if U.S.- and Mexican-origin inactivated H7 vaccine would protect birds from clinical disease and shedding of virus. In the first set of experiments, four phylogenetically-related U.S. low pathogenic avian influenza (LPAI) isolates, either H7N2 or H7N3, were formulated into inactivated emulsion vaccines and injected into 7 week old SPF birds. These isolates contained between 92-97 amino acid similarity to the hemagglutinin gene of the challenge virus (A/chicken/Jalisco/CPA1/2012 H7N3). The APHIS-approved H7 vaccine antigens were included into this experiment for testing. Birds were challenged at 10 weeks of age with 106 EID50 per bird delivered via intranasal route. Results demonstrate that three of the four H7 vaccine isolates tested provided 100 % protection, whereas the fourth isolate provided 90 % protection. In the second experiment, a Mexican-lineage LPAI H7N3 isolate from wild birds, with 98 % sequence similarity to the HPAI virus, was formulated into an inactivated vaccine and applied to 2 week old birds. Birds were challenge as previously described and demonstrated 100 % protection from challenge. All vaccines tested reduced shedding of virus compared to sham vaccinated birds. Taken together, these results indicate that both U.S. and Mexican vaccine isolates can provide protection to poultry against this recent HPAI H7N3 virus.