%0 Journal Article
%T Evaluation of a Subunit H5 Vaccine and an Inactivated H5N2 Avian Influenza Marker Vaccine in Ducks Challenged with Vietnamese H5N1 Highly Pathogenic Avian Influenza Virus
%A Tze-Hoong Chua
%A Connie Y. H. Leung
%A H. E. Fang
%A Chun-Kin Chow
%A Siu-Kit Ma
%A Sin-Fun Sia
%A Iris H. Y. Ng
%A Stanley G. Fenwick
%A Cassandra M. James
%A Sin Bin Chua
%A Siang Thai Chew
%A Jimmy Kwang
%A J. S. M. Peiris
%A Trevor M. Ellis
%J Influenza Research and Treatment
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/489213
%X The protective efficacy of a subunit avian influenza virus H5 vaccine based on recombinant baculovirus expressed H5 haemagglutinin antigen and an inactivated H5N2 avian influenza vaccine combined with a marker antigen (tetanus toxoid) was compared with commercially available inactivated H5N2 avian influenza vaccine in young ducks. Antibody responses, morbidity, mortality, and virus shedding were evaluated after challenge with a Vietnamese clade 1 H5N1 HPAI virus [A/VN/1203/04 (H5N1)] that was known to cause a high mortality rate in ducks. All three vaccines, administered with water-in-oil adjuvant, provided significant protection and dramatically reduced the duration and titer of virus shedding in the vaccinated challenged ducks compared with unvaccinated controls. The H5 subunit vaccine was shown to provide equivalent protection to the other two vaccines despite the H5 antibody responses in subunit vaccinated ducks being significantly lower prior to challenge. Ducks vaccinated with the H5N2 marker vaccine consistently produced antitetanus toxoid antibody. The two novel vaccines have attributes that would enhance H5N1 avian influenza surveillance and control by vaccination in small scale and village poultry systems. 1. Introduction Control of the H5N1 highly pathogenic avian influenza (HPAI) epizootic in village communities in Southeast and East Asia since 2003 has been difficult. Conventional control methods used for HPAI, including quarantine, enhanced biosecurity, and stamping-out are often not logistically possible in these villages where nutrition and livelihoods depend on low intensity poultry production. Use of vaccination against H5N1 avian influenza has become an important control tool in these settings [1]. All avian influenza control programs have the goals of protection from diseases, inhibition of further virus replication and transmission. Where vaccination is used, clinical disease may be prevented but ongoing surveillance is essential to monitor if the virus is still present or circulating in the avian population [1]. Ducks and other members of the Anatidae family are natural host species of influenza A viruses [2]. Prior to 2002, H5 or H7 subtype avian influenza viruses that were highly pathogenic for terrestrial poultry were generally non- or mildly pathogenic for ducks, but from late December 2002 circulating H5N1 HPAI viruses have been shown to be highly pathogenic for farmed and wild ducks and a range of other wild bird species [3¨C5]. H5N1 viruses isolated from the H5N1 HPAI epizootic that commenced in 2003 have shown some variation
%U http://www.hindawi.com/journals/irt/2010/489213/