A new piece in the puzzle of the novel avian-origin influenza A (H7N9) virus

Abstract

ReviewersThis article was reviewed by Prof Xiufan Liu (nominated by Dr Purificacion Lopez-Garcia) and Prof Sandor Pongor.Using phylogenetic analysis on newly available sequences, we characterize A/chicken/Jiangsu/RD5/2013(H10N9) as currently closest precursor strain for the NA segment in the novel avian-origin H7N9 virus responsible for an outbreak in China. We also show that the internal segments of this precursor strain are closely related to those of the presumed precursor for the HA segment, A/duck/Zhejiang/12/2011(H7N3), which indicates that the sources of both HA and NA donors for the reassortant virus are of regional and not migratory-bird origin and highlights the role of chicken already in the early reassortment events.

Novel Avian Influenza A(H7N9) Virus in Tree Sparrow, Shanghai, China, 2013

“…The number of new cases has increased sharply since January 1, 2014, paralleling the peak of the first wave ( 1 , 3 , 4 ), indicating that subtype H7N9 viruses were circulating asymptomatically among natural hosts. Sequence data indicated that the hemagglutinin gene of this novel subtype H7N9 virus might originate from a subtype H7N3 virus in ducks and that the neuraminidase gene probably originated from a subtype H7N9 virus in wild birds ( 5 ) or ducks or chickens ( 6 , 7 ). These data suggest that wild birds might play a role in the emergence of subtype H7N9 viruses, similar to the role they played in the geographic spread of avian subtype H5N1 viruses ( 8 ).…”

Recombinant virus-like particles elicit protective immunity against avian influenza A(H7N9) virus infection in ferrets

“…Most human infections have been the result of exposure to infected poultry or with environments where animals are housed [1,2]. Multiple reassortment events resulted in a novel H7N9 virus with six internal genes derived from an avian influenza A(H9N2) virus [1,3–5]. Despite the considerable morbidity and mortality caused by H7N9 virus, no sustained human-to-human transmission of this subtype has been documented.…”