You don't need modern transportation to fuel a flu pandemic

The H1N1 “swine flu” emerged in California and Mexico just about a year ago and made its way around the globe in about two months. Would it have spread more slowly without the benefit of planes, trains and automobiles?

Perhaps, but not by much. That’s the conclusion of a new study examining the spread of the 1889 Russian flu.

Back in 1889, Russia and 18 large European countries were connected by more than 125,000 miles of railroad (more than are in place today). A transatlantic journey by boat lasted less than six days – not quite as quick as it is now (though perhaps comparable to the recent experience of airline passengers stranded in Europe by Iceland’s Eyjafjallajokull volcano).

So, how long did it take for the virus to circumnavigate the globe? Less than four months, according to a report by French researchers published online Monday in Proceedings of the National Academy of Sciences.

The researchers examined public health records in 96 European and American cities, along with data from the French, British, Swiss and German armies. After St. Petersburg hit peak mortality in late November of 1889, it took three weeks for peak mortality to hit Germany, two more to reach Paris, and one week beyond that to make it all the way to the United States. On average, the virus spread through Europe at a rate of 245 miles per week. In the U.S., it traveled at the rate of 631 miles per week.

The Russian flu itself was not terribly deadly – between 0.1% and 0.28% of people sickened with the virus died from it. That puts it squarely in the range of the 1957 Asian flu and the 1968 Hong Kong flu. (By comparison, the fatality rate of the 1918 Spanish flu was about 10 times higher.)

Mathematical models suggested that speedy international air travel was not a crucial factor in the spread of the swine flu and that grounding flights would have been pointless. The French researchers say their results bolster that theory.

-- Karen Kaplan

Photo: This map plots the Russian flu's spread across Europe week by week. Credit: A.J. Valleron / National Institute of Health and Medical Research, Paris

Comments

[Sharon]

I found this video on You Tube that really shows how germs and viruses spread. It is so cool. It's meant for kids but I even learned a lot!
http://www.youtube.com/watch?v=56mq1t1BqfY

[D. Rhodes, MSPH]

Cool info but not the greatest study design to answer the question in my humble opinion. Flu case reporting is poor so is just too gross of a measure to be accurate for this purpose.
I personally just got my first nasty cold of the year only hours after getting off a long plan ride. That's doing all the right preventative things short of wearing an N99 respirator. Somebody spread that cold to me according to the length of the incubation period plus a portion of the flight time. I stepped off the paln a few hors later ready to spread the virus in a whole new city. Therefore, a case of flu travels (or speads) precisely as fast as the person with the case of flu travels plus incubation time. This means it's hours or days faster by plane than by other travel modes.

Airport terminals and airplane cabins are apparently efficient viral airborne and surface contamination spreading environments. With security what is is you can't even carry a decent quantity of antiviral foaming antiseptic to use on the plane and they don't have dispensers off antiseptic for passenger use. I have seen a few crew members using disposable gloves - which may help protect them but doesn't do much to prevent spread between passengers at the hands of the stewards.

So, banning air travel probably just slows the first transmission case a bit. Once it is in the population it is still potentially an exponential explosion of cases for highly contagious viruses and a delay of even a few weeks will not allow adequate time for a government to react effectively.