human reservoirs, piggy viruses?

A threesome of papers were out in this week's issue of Science that explained how the H1N1 virus that swept the globe in 2009 is structurally similar to the 1918 virus.

Where was that bad boy for those 91 years? Pigs.

Actually, it's more a question of time scale. Humans, who get flu every year or so, the virus changes shape quickly, which changes what antibodies can bind to and destroy the virus. Human immunity for the seasonal flu changes quickly to keep up, but abandons the old antibody shapes. So, it's really no wonder that most of us didn't have antibodies that could react to a virus that looked like the 1918 flu.

Pigs, with shorter lifespans than humans, don't see as many infections in their lifetimes so there is less changing of shape, called "drift." Pigs had inadvertently "archived" a virus that looks much like the 1918 virus, now affectionately known as H1N1, just because the infection rate and subsequent mutation rate were kept down.

So, in 2009 the pigs' version of the virus started infecting probably what might of been just a few people and then took off like wildfire, causing an impressive pandemic.

All this has me thinking if humans could be "archivers" of animal viruses. Or, based on the theory of quick vs. slow drift, if we are harbingers of doom who change viruses so quickly pig (or other animals) immune systems can't keep up.