Active reassortment of H9 influenza viruses between wild birds and live-poultry markets in Korea

Abstract

Surveillance of H9 avian influenza viruses in Korean live-poultry markets from September 2004 through October 2007 was carried out to investigate active reassortment between wild migratory birds and domestic poultry in Korea. Antigenic and phylogenetic analyses showed that most of the isolates belong to the previous Korean H9N2-like lineage and differ from the southeastern Chinese strains. Interestingly, the Ck/Korea/LPM77/06 group (genotype B) and Dk/Korea/LPM248/07 group (genotype C) showed unique properties distinct from those of other Korean H9N2 strains. Although the HA genes of these two groups belong to Korean H9N2-like lineage, the PA genes closely resemble those of the Chinese Y280-like lineage. In addition, the PB2 genes of the Dk/Korea/LPM248/07 group were closely related to those isolated from migratory birds. Several other isolates also clustered within the H9N2 B genotype, an indication that there are at least two predominant H9N2 influenza genotypes in Korea. Another isolate, Dk/Korea/LPM71/06, was identified as an H9N1 subtype, the first ever discovered in Korean live-poultry markets. These findings reveal that reassortment of Korean H9 influenza viruses has occurred frequently in live-poultry markets and may have been mediated by introduction of genetic material from viruses circulating among migratory wild birds to domestic birds. Consequently, the new dominant H9N2 genotypes have become established in Korean live-poultry markets through continued reassortment.

Rapid evolution of low-pathogenic H9N2 avian influenza viruses following poultry vaccination programmes

“…The genotype A viruses (Ck/ Korea/SH0802/08 and Dk/Korea/CBU08107/08) possessed the sequences PQVASGRQG and PQAASGRQG, respectively. The latter cleavage motif is similar to those of Ck/Korea/04116/04-like viruses reported recently (Moon et al, 2010). Relative to Ck/Korea/01310/01, there were at least four substitutions observed among the prospective antigenic sites at positions 116, 133, 145 and 189 (H9 numbering) in the HA1 region of H9 as described by Kaverin et al (2004) (Table 2).…”

“…Recently, most H9N2 viruses circulating in Korean poultry farms have further formed two antigenically distinct groups: Ck/Korea/25232-96006/96-like (1996 to mid-2003 isolates) and Ck/Korea/04116/04-like (late 2003 and 2004 isolates) (Lee et al, 2007). However, we have shown previously that more recent H9 isolates (late 2004-2007 surveillance data) from live-poultry markets (LPMs) are already more phylogenetically and antigenically related to the latter group (Ck/Korea/04116/04-like) (Moon et al, 2010). Apparently, these isolates have undergone significant antigenic drift and shift with wild aquatic AIVs that has somehow altered their pathogenicity in experimental animals.…”

Complex Reassortment of Multiple Subtypes of Avian Influenza Viruses in Domestic Ducks at the Dongting Lake Region of China

“…Of the four human pandemic influenza viruses, at least half, the 1957 H2N2 "Asian flu" and the 1968 "Hong Kong flu," emerged in southern China (58). It is generally accepted that live poultry markets play an important role in the ecology of AIV (17,18,(59)(60)(61)(62)(63)(64)(65). In 1996, the first avian H5N1 influenza virus was isolated in Guangdong Province, in southern China (22,66).…”

Genetic analysis of polymerase complex (PA, PB1 and PB2) genes of H9N2 avian influenza viruses from Iran (1999 to 2009)

“…This finding suggests a high degree of diversity among the H9N2 viruses in the regions of the Middle East and Indian sub-continent. In recent years, novel genotypes of H9N2 avian influenza viruses from domestic poultry in China, Korea, Vietnam, India and Pakistan have been identified and well characterized [27][28][29][30][31][32][33][34] . In February 2006, highly pathogenic H5N1 virus was isolated from wild birds in Northern provinces of Iran [28] .…”