STUDY OF THE INTRAVENOUS PATHOGENICITY INDEX OF THE AVIAN INFLUENZA VIRUS ISOLATE A/CYGNUS CYGNUS/KARAKOL LAKE/01/2024

This study presents the results of a comprehensive investigation of the biological properties of the highly pathogenic avian influenza virus isolate A/Cygnus cygnus/Karakol lake/01/2024 (H5N1), obtained during the 2023–2024 outbreak in the Mangystau region of the Republic of Kazakhstan. The pathogenicity of the isolate was evaluated in 6-week-old SPF chickens, along with its reproductive activity in developing chicken embryos. The virus demonstrated high virulence, causing 100% mortality of infected embryos within 48 hours and exhibiting a maximal intravenous pathogenicity index (IVPI = 3.6). These findings confirm that the isolate belongs to the highly pathogenic H5N1 variants.

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