Tuesday, April 11, 2017

NPR: A Pessimistic Guan Yi On H7N9's Evolution

Credit FAO - April 5th


Although at times it feels like playing a broken record, for the past 4 years we've spent a great deal of time examining the evolutionary progress of avian H7N9.   From the beginning, this (initially) Low Path H7 virus has been an anomaly in the field of influenza.

Benign in birds, it was able to produce severe - even life threatening - illness in humans. A further surprise was that an H7 virus could be so virulent in humans, as all other H7 viruses before it had produced only mild illness in people.

It spread stealthily among poultry, often with the first sign of infection coming when a human in close contact fell ill, and very early on we began to see it diversify into numerous genotypes as it adapted to hew host species (see Eurosurveillance: Genetic Tuning Of Avian H7N9 During Interspecies Transmission).

While efficient human-to-human transmission of the virus has not been documented, a number of small clusters have been recorded.  Over the past few years the CDC's IRAT ( Influenza Risk Assessment Tool) has ranked H7N9 as having the highest pandemic potential of 11 novel viruses currently being tracked.

Just over a month ago, in light of the record breaking number of cases in China this year, the emergence of a new lineage of the virus, and the discovery of an new HPAI strain, the CDC updated their Risk Assessment On China's H7N9 Virus. Additionally,  we've seen two detailed MMWR Reports on H7N9 this winter:
MMWR:Increase in Human Infections with Avian Influenza A(H7N9) In China's 5th Wave
MMWR: Assessing The 4th Epidemic Wave Of H7N9 In China

So, to say there is legitimate concern out there over H7N9's evolution is an understatement.

Today NPR has an interview with renown virologist Dr. Guan Yi from the University of Hong Kong, who who played a pivotal role in the identification of the SARS virus early in the last decade. He has since moved on to avian flu and is acknowledged as one of the world's greatest experts on H7N9.

Follow the link below to read his less-than-reassuring take on the future path of H7N9.

Why Chinese Scientists Are More Worried Than Ever About Bird Flu

Heard on Morning Edition

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