SYDNEY, Australia -- Two centuries ago, many travelers arrived in Australia from England after months at sea, many of them ankle-chained below deck as convicts on crammed transport ships. Some didn't make it.
Now, travelers can zip back and forth between Sydney and London in 20-hour flights, but these days they may be pinioned by safety belts into economy-class seats laid out in knee-crunching rows.
Some of them aren't making it, either.
A mysterious ailment called "deep vein thrombosis" (DVT) appears to be causing a number of casualties -- some fatal. The ailment is believed to be caused by blood clots forming from prolonged immobility and dehydration -- just the cocktail of conditions on long-haul flights.
Without a doubt, the Sydney/London "Kangaroo Route" is one of the most punishing aviation experiences available for your consumer dollar. Between the drastic time change, the uncomfortable seats and the hours idly passed watching boring movies, it can take days to feel yourself again. Thus, it's quite possible any link between long flights and health-related ailments may turn up here sooner than elsewhere.
At this point, researchers say there's no conclusive, definitive link between air travel and DVT -- which some claim could just as easily come from sitting still too long in a bus, car or Silicon Valley cubicle. But a mounting record of deaths possibly linked to DVT among passengers getting off long flights is making observers sit up and take notice.
For instance, last October, 28-year-old Emma Christoffersen collapsed in the arrival hall of London's Heathrow airport after flying home from Australia following the Olympic Games. She later died in a London hospital. In November, 68-year-old U.K. pensioner Thomas Lamb died at a Melbourne hospital after lapsing into a coma following breathing difficulties that developed after he got off a flight from London.
At both ends of the Kangaroo Route, hospitals report that cases of DVT possibly linked to air travel are far from uncommon. Rough estimates are that tens of thousands of cases may occur each year, but not all are fatal.
After a meeting at Sydney Airport last week, a group of airlines, academics and doctors agreed to study the problem over the next several years, focusing first on Australia's geographically isolated but often globally peripatetic populace.
"We're a large island nation, and therefore we're the people who travel on long-haul flights to get to U.S. and European centers," said Paul Bates, research director of the Center for Aviation Medicine and Human Factors at Griffith's University in Queensland.
The center plans to conduct the study along with the Australasian Society of Thrombosis and Hemostasis.
But with at least 20,000 volunteers needed -- and no source of funding -- conclusive results about the real risks of DVT are about as close at hand as a delay-free day at a major city airport.
At this point, experts estimate the risk of deep vein thrombosis occurring in the average air traveler to be something like one in 2 million. However, higher-risk groups such the obese, elderly and/or those with an existing history of DVT may have a risk of one in 100,000.
One means of shaking potential blood clots free on a long flight is to get up and move about. But solutions like this are likely to earn the enmity of other passengers, particularly if they happen around cattle-class feeding time. In addition, sudden turbulence could also pose a risk to the untethered, experts warn.
Instead, more effective measures may be just to wear loose clothing, experts say. They also recommend periodically massaging the calves, assuming the otherwise well-meaning person in front of you hasn't put his seat all the way back and blocked any chance of you leaning forward. A third idea is to avoid such limb-enlivening combinations as sleeping tablets and alcohol.
In public statements, airlines are clearly choosing their words carefully. They're largely taking the view that passengers should consult their physicians, and weigh the risks of being strapped into shoebox-sized seats that keep getting smaller. However, many also plan to include warnings on tickets, as well as information about the problem on corporate websites, inflight magazines and videos.
Even so, at least one law firm isn't waiting on standby any longer.
The Melbourne law firm of Slater & Gordon says it plans to sue some of the world's airlines for compensation and has collected preliminary information about roughly 2,300 alleged cases of DVT, including 116 possible deaths, says Natalie Snelling, spokeswoman for the firm.
The firm is now investigating the details of individual cases, and hopes to decide in the next month or two whether to pursue the cases individually or as a class-action suit.
Snelling hedged when asked on what grounds the cases might be filed, saying it would be premature.
