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Lisa Schnirring at CIDRAP News continues to provide the best daily summation of H7N9 news, last night taking a look at the ECDC Rapid Risk Assessment released yesterday, and detailing the latest 8 cases reported out of China.
I would invite you to read Lisa’s report in its entirety, and after you return I’ll have a bit more on the history of influenza coinfections.
Analysis of new H7N9 wave warns of coinfection threat
Lisa Schnirring | Staff Writer | CIDRAP News
Jan 28, 2014
Though ongoing H7N9 influenza activity in China—with eight new cases reported today—is mainly a zoonotic event, its parallel rise with seasonal flu poses a virus reassortment threat, according to a new assessment today from European health officials.
Activities surrounding Chinese New Year on Jan 31 will put humans in the crosshairs of both H7N9 and seasonal flu strains, according to the European Centre for Disease Prevention and Control (ECDC) in a comprehensive look at China's second wave of disease activity and its first update since May 2013.
Three Chinese provinces reported H7N9 cases today: four from Zhejiang, three from Guangdong, and one from Jiangsu.
Proof (as if we needed it) that mother nature doesn’t play fair: While not common, it is possible for a human to be infected by more than one respiratory virus at the same time.
This can not only confuse and complicate a patient’s diagnosis and treatment, it can – in rare instances – result in the creation of a new, hybrid virus.
Last summer, in Lancet: Coinfection With H7N9 & H3N2, we looked at an early report on just that type of coinfection in a 15 year-old boy living in China - and while no reassorted virus was detected - this is precisely the scenario a novel virus needs in order to quickly evolve into a more transmissible pathogen.
In 2011 we saw an influenza co-infection in Canada that led to the creation of a unique hybrid reassorted virus (see Webinar: pH1N1 – H3N2 A Novel Influenza Reassortment).
In this case, the patient was a 16-month old boy from the Greater Toronto Area who was admitted briefly to a local hospital for respiratory and gastrointestinal symptoms in January of 2011. The child was sent home, and recovered without incident, and no other family members or contacts reported flu-like symptoms.
In 2010, in EID Journal: Co-Infection By Influenza Strains, I wrote about a study in New Zealand during the opening months of the 2009 pandemic that discovered at least 11 co-infections (out of 1,044 samples tested) with the older seasonal H1N1 virus and the newly emergent pandemic H1N1 virus.
While rarely detected, influenza A coinfections are probably more common than we realize. Luckily, most do not result in the production of a hybrid strain, else we’d be hip deep in novel viruses all the time.
But the reality is, while rare, reassortments (in any host, not just humans) are a fast track for viral evolution and development, and can quickly change alter a virus’s ability to infect and transmit efficiently. So while we watch H7N9 intently for signs of change, we are also watching for any new H7 inspired hybrids to emerge.
