The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholars Program

GVSP Summer 2006 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Sue Goetz University of Minnesota Class of 2008	Dr. David Swayne

Pathogenicity of Recent Nigerian H5N1 Avian Influenza Viruses in White Leghorn Chickens

Sue K. Goetz* and David E. Swayne
Southeast Poultry Research Laboratory, USDA, ARS, Athens, GA

Concerns about the fast-moving extremely lethal highly pathogenic avian influenza epidemics among poultry flocks and the potential for zoonotic transmission make the characterization of newly discovered strains imperative. In this study, we analyzed three isolates of a previously undescribed strain of H5N1 avian influenza;
A/chicken/Nigeria/228-5/2006 (H5N1) [228-5], A/chicken/Nigeria/228-6/2006 (H5N1) [228-6], and A/chicken/Nigeria/228-10/2006 (H5N1) [228-10]. The virus was administered either by the natural intranasal (IN) route or by intravenous (IV) injection into the brachial veins of four-week-old white leghorn chickens. All three of the viruses were highly pathogenic, killing all IV inoculated chickens within two days. The mean death times for IV injected chickens were 1.125, 1.000, 1.375 days for 228-5, 228-6 and 228-10 respectively. The mean death time for 228-5 administered by the intranasal route was 2.125 days. All of the isolates produced hemorrhages in multiple organs, but gross lesions were less noticeable in birds inoculated by the intranasal route. Tissue samples were collected from the organs for histological analysis and viral titers. The results from these analyses will contribute to the understanding of the pathogenesis of these viruses. Based on the criteria set forth by the OIE, we determined these isolates to be highly pathogenic avian influenza.