Table 1. Pathogenicity and virus recovery of the Korean H5N8 HPAI viruses in chickens.

^*Number of virus isolated/number of tested samples. Virus re-isolation from swab samples from experimentally inoculated and contact chickens. In experiment 1, eight chickens were inoculated intranasally with 10^6.5 EID₅₀/0.1 mL of Gochang1 or Buan2 virus, and three chickens were co-housed with the infected chickens as the contact group. Experiment 2 was conducted to further evaluate transmissibility of the Buan2 virus. Eight 5-week-old SPF chickens were co-housed as a contact group with three SPF chickens intranasally inoculated with Buan2 virus. Oropharyngeal and cloacal swab samples were collected on the indicated day, and the virus titer was measured in chick embryo fibroblasts. Virus titer is the average of the calculable positive samples. IVPI: intravenous pathogenicity index, MDT: mean death time, HI: hemagglutination inhibition, NT: not tested, NA: not applicable. OP; oropharyngeal swab sample, CL; cloacal swab sample.