Doctor Reginald Lord of Sydney, Australia estimates that over 400 people arrive at the city's airport suffering from economy class syndrome, the deadly blood clot condition that strikes passengers on long-haul airline flights. Also known as deep vein thrombosis, economy class syndrome affects those who remain stationary for extended periods of time. Such physical inactivity may encourage the formation of blood clots in the legs. If these clots are dislodged they may make their way to the lungs or brain where they can be fatal.

Doctor Lord estimates that he sees such blood clots almost weekly. ``Now we think, and this is just an estimate, that...there may be say 400 of similar types of patients arriving at Sydney airport annually,'' said Lord, who is also a professor of surgery at the University of New South Wales. Lord says that he has been concerned about economy class syndrome for years and has repeatedly urged airlines to advise passengers of the risk.

After much recent publicity, including the threat of lawsuits by hundreds of afflicted travelers against over 20 airlines, several airlines have begun warning passengers of the dangers associated with long-haul flights. Experts recommend that passengers partake in light exercise while in transit, avoid alcoholic beverages, and drink plenty of water. "Some of us are persuaded that there is a genuine link between travel and this condition. We are in a broad state of ignorance. We need to fill that in," Dr. Lord said.