12.08.2015

Bi et al (2015) Sci Rep.

Approximately 100 migratory birds, including whooper swans and pochards, were found dead in the
Sanmenxia Reservoir Area of China during January 2015. Located approximately 1150 kilometers (km) east of Qinghai Lake, this location is an important wintering habitat for whooper swans and various species of wild ducks including pochards (Aythya ferina) migrating to China from Mongolia and Siberia.
The causative agent behind this outbreak was identified as H5N1 highly pathogenic avian influenza virus (HPAIV). Genetic and phylogenetic analyses revealed that this Sanmenxia H5N1 virus was a novel reassortant, possessing a Clade 2.3.2.1c HA gene and a H9N2-derived PB2 gene. Sanmenxia Clade 2.3.2.1c-like H5N1 viruses possess
the closest genetic identity to A/Alberta/01/2014 (H5N1), which recently caused a fatal respiratory
infection in Canada with signs of meningoencephalitis, a highly unusual symptom with influenza
infections in humans. Furthermore, this virus was shown to be highly pathogenic to both birds
and mammals, and demonstrate tropism for the nervous system. Due to the geographical location
of Sanmenxia, these novel H5N1 viruses also have the potential to be imported to other regions
through the migration of wild birds, similar to the H5N1 outbreak amongst migratory birds in
Qinghai Lake during 2005.