Despite being an LPAI (low path avian influenza) virus, and producing relatively mild symptoms in humans, H9N2 is viewed by many as an important and influential player in the avian flu world.
So, while H9N2 may not be at the very top of our pandemic threats list, it is still regarded as having at least some pandemic potential (see CDC IRAT SCORE), and several candidate vaccines have been developed.
All of which brings us to a fascinating report, published overnight in Emerging Microbes and Infections, that provides the details of an investigation of a cluster of H9N2 infections (human x 2, chickens, and a pet cat) in Guangxi, China in October of 2018.
A check of subsequent monthly WHO Influenza at the Human-Animal-Interface reports (here, here, here, here, and here) shows that China reported 6 H9N2 cases between Nov 1st 2018 and April 2019 - all among young children - but these two cases do not appear.
In addition to the infection of the family cat (see A Dog & Cat Flu Review), this outbreak is unusual in that most H9N2 cases are one-off, and we rarely hear of clusters of infection. Of note, the two human cases reported atypical (non-respiratory) symptoms of diarrhea, abdominal pain, and arthralgia.
We also learn from this report that the H9N2 clade 1.2, lineage Y280 virus detected had an exclusive binding preference for mammalian (a2,6) receptor cells, and could replicate and cause pathological changes in mice.
This is a lengthy, and highly detailed report, and is well worth reading in its entirety. I've only posted some excerpts, so follow the link to read: