APPLICATION OF BIOLOGICAL AND MOLECULAR TECHNIQUES TO THE DIAGNOSIS AND CONTROL OF AVIAN INFLUENZA AND OTHER EMERGING POULTRY PATHOGENS
Location: Exotic and Emerging Avian Viral Diseases Research Unit
Title: Update on poultry viral diseases research conducted at Southeast Poultry Research Laboratory
Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2010
Publication Date: July 15, 2011
Citation: Pantin Jackwood, M.J., Swayne, D.E., Spackman, E., Suarez, D.L., Afonso, C.L., Miller, P.J., Zsak, L., Day, J.M., Yu, Q. 2011. Update on poultry viral diseases research conducted at Southeast Poultry Research Laboratory [abstract]. Proceedings of the United States Animal Health Association 114th Annual Meeting, November 17, 2010, Minneapolis, MN. p. 526-527.
The Southeast Poultry Research Laboratory does intramural research for the United States Department of Agriculture on several poultry diseases. Following are some of the research accomplishments from last year. In the area of influenza research, we demonstrated that laying turkey hens inoculated with the pandemic H1N1 influenza virus can be infected by the intraoviduct route. This new route of transmission explained the introduction of the virus into turkey flocks through routine artificial insemination. Chicken layers became infected when inoculated by the intranasal, intracloacal or introviduct routes with a type H6N2 low pathogenic avian influenza (LPAI) virus, but not with a type H9N2 virus, indicating that LPAI viruses can also transmit in chickens through other routes besides the intranasal route, but this transmission depends on the virus. An H5N1 highly pathogenic (HPAI) virus was transmitted to ferrets and chickens by exposure to airborne virus generated during simulated home slaughter of infected chickens; however, usage of vaccinated chickens blocked H5N1 HPAI virus transmission to ferrets. In addition, conducting the slaughter in a plastic bag greatly reduced the virus transmission through the air to ferrets. Canine influenza of the H3N8 subtype, which is endemic in the US, was shown to be nonpathogenic in chickens, turkeys and domestic ducks. Work continues with antigenic cartography to develop antigenic maps of the H5, H7 and H9 subtypes with chicken sera, which will greatly facilitate the selection of optimal vaccine seed strains. Studies on vaccination of ducks and geese against H5N1 HPAI were also done. Newcastle disease research included studies evaluating the effectiveness of U.S. pasteurization standards for egg products to inactivate a low virulent NDV; the development and evaluation of two Newcastle disease virus (NDV) LaSota strain-based vaccine vectors expressing avian metapneumovirus subtype C (aMPV-C) virus glycoprotein (G) or fusion (F) and G proteins generated by reverse genetics was conducted; and the reproduction of egg malformations from vaccinated chicken layers challenged with NDV. Characterization of NDV isolates from the outbreaks that have occurred this year in Double-crested Cormorants in several states, show these viruses are mostly mesogenic but some are neurotropic velogens, and these viruses may not hemagglutinate and also be negative on the Fusion RRT-PCR assay. Research on enteric viruses included the characterization of un-described viruses present in the turkey gut, by using a pyrosequencing platform to compile an RNA virus metagenome from turkeys experiencing enteric disease. Numerous viral sequences from the dsRNA viruses (Reoviridae and Picobirnaviruses), and the ssRNA viruses (Caliciviridae, Leviviridae, Picornavirales, and Astroviridae) were identified. RT-PCR tests were developed targeting the RdRp of a novel picobirnavirus and the non-structural polyprotein region of a novel calicivirus; these primers were used to identify turkey picobirnavirus and calicivirus RNA in United States turkey flocks with enteric disease signs.