Experimental infections of herring gulls (Larus argentatus) with H5N1 highly pathogenic avian influenza viruses by intranasal inoculation of virus and ingestion of virus-infected chicken meat

The present study investigated the susceptibility of herring gulls (Larus argentatus) exposed to two strains of Asian lineage H5N1 highly pathogenic avian influenza (HPAI) virus by evenly separating six gulls into two groups and inoculating them intranasally with 10(6) median embryo infectious doses of either A/whooper swan/Mongolia/244/05 (H5N1) or A/duck meat/Anyang/AVL-1/01 (H5N1). Two additional gulls were fed 5.0 g meat from a specific pathogen free chicken that died after experimental infection with A/whooper swan/Mongolia/244/05. Morbidity and mortality were observed in the gulls infected with A/whooper swan/Mongolia/244/05 by both routes of exposure. Gulls infected with A/duck meat/Anyang/AVL-1/01 exhibited high morbidity, but no mortality. The concentration and duration of viral shedding were similar between gulls infected with either strain of H5N1 HPAI virus by intranasal inoculation and gulls exposed to A/whooper swan/Mongolia/244/05 through ingestion of virus-infected chicken meat. The susceptibility of herring gulls in this study varied between the two strains of Asian lineage H5N1 HPAI virus. These results also provide preliminary data to support that ingestion of virus-infected raw or uncooked chicken meat is a viable route of exposure to some H5N1 HPAI viruses in herring gulls. Additional studies are necessary to further evaluate the efficiency of this route of exposure to a variety of H5N1 HPAI virus strains in herring gulls and other avian species in order to better understand the potential role of scavenging species in the epidemiology of H5N1 HPAI virus.