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Dr. James S. Guy

Dr. James S. Guy

Professor, Poultry Health Management
Diplomate, American College of Veterinary Microbiologists
Diplomate, American College of Poultry Veterinarians

Phone: 919.513.6287
Fax: 919.513.6464
Email: jim_guy@ncsu.edu

Clinical Virology Lab

Education

Areas of Research/Study

Infectious proventriculitis is a transmissible disease of chickens of unknown etiology. The disease occurs commonly in broiler chickens and is associated with proventricular fragility, impaired growth ("runting"), poor feed conversion, and impaired feed digestion. Additionally, the disease is responsible for increased processing costs due to greater numbers of reprocessed carcasses, downgrades and condemnations.

Recent studies in our laboratory have identified an adenovirus-like virus (AdLV), designated R11/3, as a likely cause of this disease, and we have successfully propagated the virus in embryonated chicken eggs. In inoculated embryos, AdLV (R11/3) is detectable in proventricular tissues, and produces necrosis and inflammatory lesions consistent with the naturally occurring disease. The principal aim of current studies is to 1) determine antigenic relationships between AdLV (R11/3) and other known avian adenoviruses (groups I, II, III), 2) determine genomic relationships using polymerase chain reaction (PCR) procedures, 3) clone and sequence AdLV (R11/3) DNA and compare sequences with known avian and mammalian virus sequences, 4) evaluate the ability of AdLV (R11/3) to experimentally reproduce proventriculitis in SPF chickens, 5) evaluate the feasibility of AdLV (R11/3) immunization for preventing proventriculitis in chickens. Enteric diseases of young turkeys also are a focus of our research efforts. These diseases are the most significant cause of lost economic potential in the turkey industry and likely are responsible for lost income of well over $300 million dollars annually in the US. Turkey coronavirus (TCV) and turkey astrovirus (TastV) are currently under study in the laboratory. Studies in progress are aimed at 1) determining antigenic and genomic relationships between TCV and other avian and mammalian coronaviruses, 2) developing improved diagnostic procedures for TCV and TAstV, 3) determining methods of TCV and TastV transmission, and 4) determining the mechanisms of TCV and TastV pathogenesis. Improved diagnostic procedures for TCV are being developed utilizing results of gene sequencing studies. These diagnostic procedures include reverse transcriptase-PCR procedures for rapid detection of the virus in infected turkeys, and a competitive enzyme-linked immunosorbent assay for serological detection. The competitive enzyme-linked immunosorbent assay is based on antigen derived by expression of TCV nucleocapsid protein by a recombinant baculovirus previously produced in the laboratory. Immunohistochemical procedures for TCV and TastV based on monoclonal antibodies also are being developed.

TCV has been associated as a cause of high mortality in young turkeys; however under laboratory conditions the virus causes diarrhea and growth depression without significant mortality. High mortality in young turkeys has been experimentally reproduced by dual infection with TCV and enteropathogenic strains of E. coli (EPEC). Turkeys inoculated with only EPEC do not show clinical signs of disease. The method(s) by which TCV potentiates EPEC infection resulting in severe disease is the focus of studies in the laboratory. In additon, the prevalence of TCV, TAstV and EPEC in field cases of enteric disease in turkeys is being investigated. Therapeutic amelioration of severe enteric disease in young turkeys is being studied using TCV and EPEC as an experimental model.

Appointments and Honors

Representative Publications

Scientific Papers

Book Chapters