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Flu in all Forms, Be Informed...Not Panicked.
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Rescooped by Mel Melendrez-Vallard from Virology News
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Potential for H3N2 influenza pandemic

Potential for H3N2 influenza pandemic | Influenza | Scoop.it

The 2009 swine-origin H1N1 influenza, though antigenically novel to the population at the time, was antigenically similar to the 1918 H1N1 pandemic influenza, and consequently was considered to be [ldquo]archived[rdquo] in the swine species before reemerging in humans. Given that the H3N2 is another subtype that currently circulates in the human population and is high on WHO pandemic preparedness list, we assessed the likelihood of reemergence of H3N2 from a non-human host. Using HA sequence features relevant to immune recognition, receptor binding and transmission we have identified several recent H3 strains in avian and swine that present hallmarks of a reemerging virus. IgG polyclonal raised in rabbit with recent seasonal vaccine H3 fail to recognize these swine H3 strains suggesting that existing vaccines may not be effective in protecting against these strains.

 

Vaccine strategies can mitigate risks associated with a potential H3N2 pandemic in humans.


Via Ed Rybicki
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Ed Rybicki's curator insight, May 13, 2013 10:24 AM

No-one think of H3N2...except, as it happens, these folk - who have shown quite convincingly that circulating strains of H3N2 in birds and pigs would be quite capable of avoiding vaccine-conferred immunity, and potentially of causing a pandemic, if they reassorted with human-infecting viruses.  

 

I can't help but feel that there are several ticking influenza pandemic time bombs out there...H5N1, H7N9, and now H3N2.

Rescooped by Mel Melendrez-Vallard from Virology News
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PLOS Pathogens: Environmental Predictors of Seasonal Influenza Epidemics across Temperate and Tropical Climates

PLOS Pathogens: Environmental Predictors of Seasonal Influenza Epidemics across Temperate and Tropical Climates | Influenza | Scoop.it

Human influenza infections exhibit a strong seasonal cycle in temperate regions. Recent laboratory and epidemiological evidence suggests that low specific humidity conditions facilitate the airborne survival and transmission of the influenza virus in temperate regions, resulting in annual winter epidemics. However, this relationship is unlikely to account for the epidemiology of influenza in tropical and subtropical regions where epidemics often occur during the rainy season or transmit year-round without a well-defined season. We assessed the role of specific humidity and other local climatic variables on influenza virus seasonality by modeling epidemiological and climatic information from 78 study sites sampled globally. We substantiated that there are two types of environmental conditions associated with seasonal influenza epidemics: “cold-dry” and “humid-rainy”. For sites where monthly average specific humidity or temperature decreases below thresholds of approximately 11–12 g/kg and 18–21°C during the year, influenza activity peaks during the cold-dry season (i.e., winter) when specific humidity and temperature are at minimal levels. For sites where specific humidity and temperature do not decrease below these thresholds, seasonal influenza activity is more likely to peak in months when average precipitation totals are maximal and greater than 150 mm per month. These findings provide a simple climate-based model rooted in empirical data that accounts for the diversity of seasonal influenza patterns observed across temperate, subtropical and tropical climates.


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Ed Rybicki's curator insight, March 18, 2013 2:33 AM

This is really quite a big deal: I blogged recently on the first paper that explored this notion in detail; here we see that paper vindicated, and new data presented.

 

It is interesting that the virus should have evolved to be spread in this way: in drier cold air in temperate climates, and in warm wet air in more tropical climes.  It also very nicely explains seasonality in influenza transmission.

 

Now, let's do something ABOUT it!

Carl Shiu's comment, March 19, 2013 8:16 AM
Interesting data. In tropical climes, I wonder if this phenomenon is associated with the overcrowding of shelters during intense rainstorms. A temporary increase in population density during these events would likely facilitate increased rates of person-person transmission.