Comparison of common genotypes of chinese H7 avian influenza viruses for replication and transmission in chickens

Authors: Suarez, David; Rodriguez, Marisela

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In 2013 an outbreak of H7N9 was detected in humans and in poultry in China. Additionally H7N7 virus was also found in poultry in China. Both groups viruses appeared to be reassortant viruses having picked 6 internal gene segments from the poultry adapted H9N2 that is endemic in China and having likely acquired the hemagglutinin and neuraminidase genes from wild birds. With both groups of viruses numerous polymorphisms were present including 3 changes in the hemagglutinin protein. One of the changes at position 217 is in the receptor binding site that typically impacts whether the virus attaches to alpha 2,3 (avian-like) or alpha 2,6 (human-like receptors) that are predicted to affect virus replication. Two other changes were found in the human isolate that is rarely found in poultry isolates. Studies were performed using reverse genetics to make viruses with the combination of these three amino acid changes to ask the question of whether these changes affect virus replication and direct virus transmission. Studies were performed in 4 week old chickens by directly inoculating some chickens and then adding naïve chickens to the same cage 2 days later. Samples from both directly inoculated and transmission birds were also directly sequenced to determine if viruses mutated to any particular genotype. Additional studies will also examine other gene segments commonly found in China to determine if a particular constellation of gene segments are more likely to transmit among poultry and provide predictions on which viruses pose the greatest risk for people and poultry.