In this week's Science magazine there is an article that seems to me to say that, of the factors in the spread of flu that the authors tested, county to county workflow (commuting) is the most significant in spreading flu across the country.
Apparently the intercounty workflow is a more important factor than air-travel, long distance travel and distance.
In thinking about my local experiences, it seems logical that if people live closer to their work then it is less likely that they'd spread the flu to someone in a different city. For example, I've worked with people in Virginia who live in Baltimore MD. If that weren't so common, the transmission of flu from Virginia to Baltimore would slow. This is a public health aspect of car-free living that I hadn't thought of before. When more people live closer to work, cross country spread of a deadly disease is slowed. This slowing could give a country time to ramp up vaccine production couldn't it?
It is interesting that the origination of flu pandemics is consistently in California.
"Turning to the onset of the national epidemic, there is a tendency for the influenza season to start in California more often than in any other state (with an average lead of 1 week for California, P < 0.01). This is consistent with California's being the most populous state; however, additional analyses indicate that population factors alone cannot explain the early epidemic onset in California ."
The article is:
"Synchrony, Waves, and Spatial Hierarchies in the Spread of Influenza" Science 21 April 2006:Vol. 312. no. 5772, pp. 447 - 451
But haven't most recent flues been of East Asian orgin? Wouldn't that be a likey cause for an earlier onset in California?
I don't have the magazine in front of me now but they studied three strains whose infections recur in the US year after year. That doesn't mean the particular variant that produced a pandemic in any year didn't first appear in East Asia. They weren't remarking on the appearance of the strain in California but on the epidemic or pandemic occurance. I've studied epidemic models but am no expert but if travel to east asia were a factor then you'd expect Washington or Oregon to also appear as places of early pandemics just as SARs first jumped to Canada from Asia didn't it?
With LA taking in so many overseas flights, I'd believe that. Infection by commuter has to be slower than by air travel. Within a region or a group of nearby cities, yeah it would be #1, but air travel will be the biggest factor in spreading a future pandemic around the globe.
There were no interstate highways, huge mega populations, mass airplane flights over extreme distances (all over the world in a matter of hours), illegal border crossings, and other migrant population shifting back in 1918. Yet the Spanish Flu wiped out an huge amount of people all over the world. Other pandemics did the same even earlier. We were lucky since 1968-the last pandemic. I think the party's over.
Well, in 1918 there was a little thing called World War I which certainly did cause tremendous population shifts, both civilian and military. Also "illegal" border crossings if you count the invasion of many countries by their eniemies.
The bubonic plague spread across Asia and Europe mainly by sea, on slow sailing ships, because that's how the rats that spread the disease travelled. Areas far from the sea that were served by land trade, like Central Asia and Siberia, were largely spared. The plague pandemic took several years to spread that far, modern travel could of course accelerate the dispersal of future pandemics. On the other hand, we have a lot of knowledge and technology that weren't available in 1318, 1918 or even 1968.
This thread brings to mind a recent conversation I had with a neighbor. She works in Homeland Security doing planning for a severe flu outbreak. She said that, internally, they are recommending personal stock piling of necessities.
For some scenarios they may implement a strict quarantine. That coupled with the disruption from the flu itself could lead an area to rapidly run of out food, gas, etc.
I can see how that could quickly become a problem since our distribution system for nearly everything has become 'just in time'. A few truck drivers get sick, road blocks for the quarantine make it difficult to get in/out, and fear could quickly cause a number of severe outages.